2021 International Aircraft Cabin Air Conference: Conference Proceedings

2 0 2 1 I N T E R N A TI O N A L A I R C R A F T C A BI N AI R C O N F E R E N C E C O N F E R E N C E P R O C E E D I N G S P r e s e n t a t i o n s , A b s t r a c t s a n d P a p e r s of t h e 2 0 2 1 I n t e r n a t i o n a l A i r c r a f t C a b i n A i r C o n f e r e n c e 1 5 - 1 8 M a r c h 2 0 2 1 O n l i n e , Z o o m Tristan Lorain (Conference Director) Diet er Schol z, Susan Michaelis (Editor s) CON FEREN CE PR OCEEDINGS 202 1 Internationa l Aircr aft Cabin Air C onfer enc e 15- 18 Ma rch 20 21 , Onli ne, Zoom London: Global Cabin Air Quality Executive (GCAQE) 20 21 3 Confer enc e Ho mep a ge : https://www .aircraftcabinair.com Confer enc e Pro cee ding s Homepage: https :// zeno do. org/c om muni ties /airc ra ftca bina ir DOI: https://doi.org/10.5281/zenodo. 6442960 URN: https :// nbn - reso lving .o r g/urn :n bn: de:g bv:1 8302 - aero2021 - 03 - 15.01 4 Associa t ed UR Ls: https :// nbn - reso lving .o r g/html /ur n: nbn: de: gbv: 1830 2 - aero 20 21-03-15 .01 4 © by au thors The work is licensed under a C reative Com mons Attribution 4.0 I nte rna tio nal Li ce nse: CC B Y https://creativec ommons. org/licenses/by/4.0 P ublis hed by Aircraft Desig n and Syste ms Group (AERO ) Depar tme nt of Au tomo ti ve and A er ona utical Eng i neeri ng Hamburg Uni versity of A pplied Science This r epo rt i s depos it ed a nd ar chiv ed : • Deuts che N ati onal bilio th ek ( https: //w ww .dnb. de ) • Repos itor ium der Le ibni z U niver sitä t H annov e r ( h ttps ://w ww .r epo.uni - ha nnove r. de ) • Inter net Arc hive ( https://archive. org ) Item: https://arch ive.org /details/AircraftCabinAir - 2021. pdf 4 A bstra ct The International Airc raft Cabin Air Conferences have developed into a se ries of c onferences tha t wer e organized so fa r in 2017, 201 9 an d 2021 . T he conferences are mapping the business, reg ulatory an d technical s olutions t o aircraft cabin air c ontamination. T he se proc ee dings contai n the c ontri bu tions to th e con fere nc e in 2021. F rom the 39 co ntri bu tio ns to the con fere nc e 33 a r e inc lud ed i n the pr oc ee dings . M ost contributions are containe d in the pr oce edi ngs i n f or m of a prese nta tio n. S ome are c on tai ned i n mo re tha n one form a t (a dding an extended abstract or a paper ). Fo r this reason the proceedings contain 48 d ocuments a nd links to 11 short documentary films, all together o n 791 pag es. Introduc tio n to the Pro c ee ding s The International Airc raft Cabin Air Conferences have developed into a se ries of c onferences tha t wer e so f a r organ ized ever y two years . T he c onf ere nce s ar e ma pping the bus ine ss, regulatory and technical solutions to aircraf t cabin air c ontamination. The con fere nc es i n 2017 , 2019 and 2021 provi de d m uc h info rm ati on for th o se see kin g to unders tand t he sub jec t of conta mina ted a ir , the flig ht s afe ty im pli c ations , the l ates t sc ientific a nd m edi cal ev idenc e i nves tiga ting t he conta mi nate d air de bat e a nd th e sol utio ns available to airli nes and aircraft op erators. T he thre e c on fere nce s held so fa r hav e bee n the mo s t in - depth confere nces ever on the topic of ai rcraft cabin air c ontamin ation. By w ay of e x per t g l obal i nd epe nde nt and i ndus try s pe ake rs, t he Air cra ft Cabin Air Confer e nces s ee k to a chi ev e the fol low ing k e y objecti ves : • P rovide a historical over view of the c ontaminated air issue and its causes. • Map o ut t he fl ight sa fe ty aspec ts o f co ntam ina te d air thr ough ca se s tu dies , disc uss io n and air accide nt inve s tig ation fi ndi ngs. • Diss emina te t he l ate st me dica l a nd s cie nti fic the o rie s a nd f indi ng s on the hea lt h as pec ts of exposure t o contamin ated air. • Give g uidanc e o f th e reg ul atory a spec ts of c abi n air q uali ty. • Exa mine th e la tes t deve lopm ent towar ds blee d ai r fil tration, co ntaminated air w arnin g sensor systems an d othe r potential solu tions. • Prov ide an o ppor tu nity for n etw orki ng an d sh aring go od pr ac tic e to fa cil ita te be tte r inter - agency w orking. T he 2021 Inte rnati onal Aircraft Cab in Air C onfe rence w as a fo ur - day fr ee modular onli ne event via Zoo m. C ontr ibut ions were gr oup ed into the se sessions : 1. Intro duc tio ns a nd t he his tor y of t he issue 2. U nders tan ding e ngin e se al s and ex pos ure 3. Global perspectives 4. Oper ati onal as pects 5. A ir A ccide nt i ncide nts a nd f i ndi ngs 6. Air monitoring a nd measuring 7. Intro duc tio n to orga nop hos phate s 8. T he toxi colog y an d neut oxi city of contaminated air 9. Occupational healt h and exposures 10. S afety analysis a nd biomark ers of ex posure 11. The legal as pec ts of co ntaminated air expos ures 12. Filtration solutions Please r efer t o the C onf eren ce Programme 2 0 21 ( ht tp s ://doi.org /10 .5281/ zenodo. 4627005 ) for a ddi tio nal i nfo rma ti on n ot rep ea ted he re : • L ist o f c onfer e nce s pea ker s • Sche dule of the c onf er ence • Sponso r s and s up por ters Th e re we re 39 contri butions to the confe rence . U nfo rtu n ately, six of them are n ot in th e p roceedin gs. Among the remaini ng 33: • 4 were give n as a S p eech . The se speeches got con vert ed to a C onf erenc e P aper . • One P resentat ion wa s pr ovi ded fo r t he proc e edi ng s only i n the for m o f a sho rt Con feren ce Pape r ( not as a pr e sen tati on ). • The r ema ini ng 28 co ntri b utio ns a re incl ude d i n the pr oce edi ngs in the for m o f a P rese ntat ion . To th es e 28 P r esent ati ons , 15 docu men ts w ere ad ded to pro vide an add iti onal for m at an d a s suc h mor e i nfor mati on : • To fife P rese nta tio ns an Exte nded Abs trac t was adde d. • To se ven P re se nt a tio n s a Confer ence Pap er w as adde d. • To o ne pr ese nta tio n a Journ al Pape r wa s adde d. • To o ne pr ese nta tio n a C o nferen ce Pap er was add ed and lat e r al so a Journal Pape r . A ll t oget her t his g ive s 33 plus 1 5, he nce i n tota l 48 do cuments t hat ar e inc l uded i n the se Pr oceedings of the 2021 In ternational Ai rcraft Ca bin Ai r Co nference . Th e proceedings are not consecutively numbered, but have a known total of 791 pages . The documents are sorted 5 6 alphabetically b y the mai n aut h or ' s last name i n the pr ocee ding s and i n it s T able of C ont ents . E ver y doc ume nt is gi ven in the T abl e o f C o nte nts with • the ti tl e tha t li nk s to the doc ume nt i n th e proce edi ngs, • a D ig ita l O bjec t I den tifi er ( DOI ) th at lin ks to the doc ume nt ' s in dividual onl in e la nding page. J o urnal pa p ers use t he DOI provi de d by the journa l. • I f the re is mo re tha n o ne fo rma t o f th e co ntri bu ti on the se quenc e is ( as far as availa ble ): 1. journa l pa per 2. conference pap er 3. exte nded abs tra ct 4. prese nta tion • I n ad diti on th e proc ee ding s hav e a PDF ta ble of conte nts ( in form of a sidebar ) , wh ich can also b e used to navigate the bulky file. Wh en i ndividual c onf ere nc e con tri bu tions are m ade available cha nce s are much hi gher the y are fou nd b y search engines. M o st l ibraries how ever , require tr adi tio nal procee dings for c opyright reasons o r bec ause their capaci ty is limited and they can d eal with on ly one sin gle docum ent f or every confer ence in their cata log and a r chiv e. An o nline re posito ry ( or " comm unity ") called " Int ernational Aircraf t Cabin Air Con ferences – Proceedings " ( https://ze nodo .o rg/communities/ aircraftcabinair ) ex ist s , which contains all the in divi dual c ont ribut ions to the confe rence s each with its own landing pa ge and a persi ste nt D igit al O bj ect I denti fie r ( DOI ). T he r e posito ry mak es us e of the O pen S cien ce S ervice "Z eno do " ( h ttps ://z enodo .org ) fun de d by the Euro pea n U ni on and run by CERN ( https : // hom e.cern ) . CE RN is a large in ternational researc h organizat ion, where ( amo ng many other achieve ment s ) the Wo rld Wi de We b wa s invent ed . T here are s everal w ays , how a c onfer e nce c o ntri bu tion c a n be q uo ted. T h ese are th e possibilities : Citatio n of the complete p r oceedin gs (ISO 6 90): SCHOLZ, D ieter, MICHAELIS, Su san ( Ed.) , 20 21 . 20 21 Inte rnational A ircraf t C abin Ai r Conference: C onference Pr oceedings . London: GCAQE. Av ailable from: https://doi.org/10.5281/zenodo.6442960 Citatio n o f a n in div idua l artic le in the pr ocee ding s (ISO 690) : LASTNAME, FirstName, 2 0 21 . A rticleTi tle. In: SC HOLZ, D ieter, M ICHAELI S, Su san ( Ed.). 20 21 International Aircraft C abin Air C onference: C onference P roceedings . London: G CAQE. Available from: https://doi.org/10.5281/zenodo.6442960 Independe nt c ita tion o f an ind ivid ua l ar ticle ( ISO 690) : LASTNAME, FirstNa me, 2 019. ArticleTitle . Pres ent ed a t the 20 21 Inte rnational Aircraft C abi n Air Conference (O nline, 15- 18 Ma rch 20 21 ). Available f rom: http s :/ /doi. org/1 0.5281/ zenodo. xxxxxxx 11 shor t documenta ry film s were present ed d uri ng the 2 02 1 I nt erna tio na l Aircraft Cabin Air Confer enc e . T he films a re stored for streaming on V imeo ( https : // vimeo.com ). A ccess t o these films is given in the s ect i on "C onference D ocumentary F ilms ". Pr esentation are i n a free f ormat, but E xtende d A bs trac t s and C onf erenc e P apers wer e edite d in a for ma t defi ned for the c onfer e nce ( h ttp s : // C ab in A ir. Pr of S chol z. de ). A uth or s were ask t o make a n att empt an d to deliver their manusc ript accor ding to t he template. A l l m anuscripts we nt th ro ugh an editori al revi ew . T hey were subs e quentl y formatted to confer e nce sta ndar ds b y the edi tor and by stu den ts from H amburg U niversity of A pplied S cien ces. P lease n ote : Neither t h e confere nce orga nizer nor the e ditor s can be he l d resp ons ibl e for inaccuracies or e rrors in any d oc umen t i n these p roc eedi ngs . Dieter Scholz an d S usa n M ic haelis (E ditors ) Introduc tio n to the C o n fer enc e The Co nfer enc e Direc to r Capta i n Tri sta n Lor ai ne we lcom ed d ele ga tes t o t he 2 02 1 Conference and tha nked the principal sp onsors Pall Aerosp ace and BASF f or their continued supp ort of t he con fere n ce. Capta in Lo r aine br ief ly di sc u sse d th e neg ati ve impa ct of COV ID on so ci et y and the a via tio n ind u stry an d ex pl ained wh y co n sequ ent ly the co nfe ren ce had moved online. 7 8 Conference Docume ntary Films Unde rstanding filtration and 'bleed ai r' https ://vime o.com/52 4184853 Differing viewpo ints https ://vime o.com/52 0900018 GCAQE GCAQE global 'Cl ean Air Campaign' https ://www.gcaqe. org/cleanair Captain Tristan Loraine BCAi Unde r reporting and GCARS https ://vime o.com/36 8028953 Michaelis et al. Ultrafine Particle Leve ls Measured On Board Shor t -haul Commercial Passenger Jet Aircraft https ://vime o.com/52 0013750 GCAQE One night near Malmo and fur ther research https ://vime o.com/52 0042108 Unde rstanding organop h osphates used in aviati on https ://vime o.com/52 0060743 Dr. Mark Mon tgome ry PhD Human Intoxication Following Inh alation Exposur e to Synthetic Jet Lubricating Oil https ://vime o.com/52 0896124 Crew exposure - a perso nal ex perien ce https ://vime o.com/52 0030089/c7ceb41990 A passenge r's perspective of contaminated air https ://vime o.com/52 2288761 A jou rney to the Hi gh Court of Australia https ://vime o.com/52 0054588 9 Tab le of C o nten ts Ari e Adriaen sen : Cabin Air Contamination Sen sor s and Eur opean Regu lati ons https ://doi.org/10 .52 81/zen odo .47 304 01 (Pres e ntati on , 27 p ages) Alessandra Airaldi: Fligh t Safety and the Key Role o f Fli gh t A ttendants https ://doi.org/10 .52 81/zen odo .49 457 88 (C onferenc e Pa per , 2 pages ) https ://doi.org/10 .52 81/ze no do .47 304 03 (Pres e ntation , 12 pages) Judi th A nd erso n: Oil Fumes, Fligh t S afety, and the NTSB https ://doi.org/10 .33 90/aeros pa ce81 20 3 89 (Journal Pap er , 20 Pages ) https ://doi.org/10 .52 81/zen odo .55 082 66 (Pres e ntati on , 36 p ages) Fran k Brehany: Air Quality: The Sta te o f St andards https ://doi.org/10 .52 81/zen odo . 555 24 94 (C on fere nc e Paper , 6 pages ) Jonathan Bu r don: Aero toxi c Syndrome, the Hear t and Organo phosph ates https ://doi.org/10 .52 81/zen odo .63 833 45 (Co nferenc e Pa p er , 3 pages) https ://doi.org/10 .52 81/zen odo .47 304 08 (Pres e ntati on , 17 p ages) Jonathan Bu r don et al.: Investigating Health and Exposure Circumstances of Persons after Aircraft Fume Events: A Narrative Review with Medical Protocol https ://doi.org/10 .52 81/zen odo .63 833 16 (Co nferenc e Pa p er , 4 pages) https ://doi.org/10 .52 81/zen odo .47304 06 (Pres e ntati on , 17 p ages) Ton y Cable: An Air Accide n t Inve stigator 's Perspective https ://doi.org/10 .52 81/zen odo .52 119 48 (C onferenc e Pa per , 3 pages ) Eoin C oates ; K ris Major: ITF/ETF Perspective o f Contaminated A ir https ://doi.org/10 .52 81/zen odo .55 584 90 (C onferenc e Pa per , 5 pages ) 10 David Conrad: Adv anced Technology F iltrati on For A Better Crew And Passenger Exper ience https ://doi.org/1 0.5 281/zenod o.489 9216 (Con fere nce Paper, 7 pages ) https ://doi.org/1 0.5 281/zenod o.473 0410 (Presentation, 12 pages) Gitte Furd al D amm: Patching up Risks? – A Vi ew on Human Factor s a nd Toxic Fumes https ://doi.org/1 0.5 281/zenod o.551 5475 (Extended Abstract, 2 page s) https ://doi.org/10.5 281/zenodo .55 153 99 (Presentation, 14 pages) Marcus Diamo nd: Cabin Air Quality Mo nitoring – Organophosphates Sampling during Fume Events in Australia https ://doi.org/1 0.5 281/zenod o.556 7738 (Extended Abstract, 2 page s) https ://doi.org/1 0.5 281/zenod o.556 7722 (Presentation, 21 pages) Mariano Di Matteo : Study on Aircraft Bleed Air Contamination by En gine Oil https ://doi.org/1 0.5 281/zenod o.551 0287 (Presentation, 14 pages) Dani el Dumali n: Aircr aft Cabin Air – Neurotoxicity: Update and in -Depth An alysis https ://doi.org/1 0.5 281/zenod o.490 4610 (Extended Abstract, 3 page s ) https ://doi.org/1 0.5 281/zenod o.473 0412 (Presentation, 22 pages) Halvor Erikstein: Two Sides of the Same Coin: Exposure to Lubr icants from Aircraft T urb ine Engine s and Offshore Aer oderivative Gas T urbine s https ://doi.org/1 0.5 281/zenod o.473 0414 (Presentation, 29 pages ) Richard Fox: Consider ations a nd Log istics F or Global G rou nd and in -Flight Trace Contaminant Testing https ://doi.org/1 0.5 281/zenod o. 4904 587 (Extended Abstract, 2 page s) https ://doi.org/1 0.5 281/zenod o.473 0418 (Presentation, 16 pages) Clemen t Fur lon g: Have You Been Exposed to Aircraft Engine Oil? - Biomarkers of Exposur e https ://doi.org/1 0.5 281/zenod o.473 0424 (Presentation, 26 pages) 1 1 Rob ert Harri son : Occupational Medicine and Con tam ina ted Air Exposure s – Quarter Decade Later https ://d oi.o rg/1 0.52 81/zeno do.5605 076 (Presentation, 11 pages) Vyvyan Howard: Toxicology of Contaminated Air: Ar e We Under estimati ng OP Exposure to Aircrew from Eng ine Bleed Air? https ://d oi.o rg/1 0.52 81/zeno do.4730 426 (Presentation, 17 pages) Glen Lasken: How to Win a Claim Arising O ut of a Fume Eve nt https ://d oi.o rg/1 0.52 81/zeno do.4939 077 (Conference Paper, 9 pages ) Victor Leun g: Ozone-VOC Conve rters: Enhance You r Comfort https ://d oi.o rg/1 0.52 81/zeno do.5501 748 (Presentation, 27 pages) Zoe Littlepage: Toxic C abin Air Litigation in the USA https ://d oi.o rg/1 0.52 81/zeno do.5605 284 (Presentation, 56 pages) Tristan Loraine: History of Contaminated Air – From 1901 to 2021 https ://d oi.o rg/1 0.52 81/zeno do.5557 722 (Conference Paper, 7 pages ) https ://d oi.o rg/1 0.52 81/zeno do.5514 195 (Presentation, 92 pages) Nicholas Mc Hugh : Contaminated Air – The Perspe ctive Of a Former Airline-Training Captai n https ://d oi.o rg/1 0.52 81/zeno do.4957 965 (C on fere nce Paper, 3 pages ) Su san Michaelis: Air Acciden t B ure au Incident Reports - Case Study Review https ://d oi.o rg/1 0.52 81/zeno do.5457 066 (Con fere nce Paper, 6 pages ) https ://d oi.o rg/1 0.52 81/zeno do.4730 428 (Presentation, 18 pages) Su san Michaelis: Cabin Air Quality: Safety Analysis and Certification https ://d oi.o rg/1 0.52 81/zeno do.4730 430 (Presentation, 18 pages) 1 2 Dragos Mun teanu : IATA Perspe ctive on Cabin Air Quali ty St andards Develop ment https ://doi.org/10 .52 81/zenod o.5508 251 (Pres e ntation, 9 pages ) Ricardo Pavia: Operational Aspects of Contaminated Ai r – An Engin eer's Perspe ctiv e https ://doi.org/10 .52 81/zenod o.5608 737 (Pres e ntation, 16 p ages) Rud y Pon t: A Breath of F resh Air – ECA's View on Ca bin Air Quality https ://doi.org/10.5 281/zenodo .560 87 56 (Pres e ntation, 7 pages ) Jonathan Sa ltm an: Air and Sur face Purifica tion System https ://doi.org/10 .52 81/zenod o.4730 432 (Pres e ntation, 19 p ages) Dieter S c holz : Aircr aft Cabin Air a nd Eng ine Oil – Route s of Contamination https ://doi.org/10 .13 111%2 F2 066-8 201.2022 .14.1.13 (Journ al Paper, 18 pages) https ://doi.org/10 .52 81/zenod o.5895 138 (C o nference Paper, 22 pages) https ://doi.org/10 .52 81/zenod o.4743 773 (Pres e ntation , 42 pages) Sarah Shabbi r: Radial Lip Seals for Aerospace Ap plication s – An Overv iew https ://doi.org/10 .52 81/zenod o.5559 762 (Extend e d Abstrac t, 3 pages) https ://doi.org/10 .52 81/zenod o.5511 963 (Pres entation, 11 p ages) Alvin V. Terry: Chron ic Low Level Exposur e to Organophosphates https ://doi.org/10 .52 81/zenod o.4904 767 (C o nference Paper, 4 pages ) https ://doi.org/10 .52 81/zenod o.4730 434 (Pres e ntation, 23 p ages) Paul I. Williams: Simultaneous Inbo ard and Outboard, Inflight Measur ements of Ultrafine Pa rticle Concen trations https ://doi.org/10 .52 81/zenod o.5605 071 (Pres e ntation, 18 p ages ) Cabin Air Contamination Sensors and European Regulations Aircraft Cabin Air International Conference 2021 Arie Adriaensen - 15 March 2021 KU Leuven University - Dpt of Mechanical Engineering Safety philosophy Interp retati on 1 Presentation structure Departmen t of Mechanica l Engin eering, Centre f or Indu strial Manag ement Flight safety - final reports Recommendations Regulations Safety philosophy Interp retati on 2 Presentation structure Departmen t of Mechanica l Engin eering, Centre f or Indu strial Manag ement Flight safety - final reports Recommendations Regulations 3 Incident Reports Root Causes 1995 - 2015 [1] Departmen t of Mechanica l Engin eering, Centre f or Indu strial Manag ement 20 4 3 28 0 5 10 15 20 25 30 Oth er /u n k n o w n De- I c in g Hyd ru a lic f l u id Oi l I d en t i f ie d 4 Incident Reports excerpts Departmen t of Mechanica l Engin eering, Centre f or Indu strial Manag ement AAIB U K “Smoke or fumes in the flig ht deck or passe nger cabin p resent the cr ew with a pote ntially h azardou s situat ion, wh ich requ ires prompt act ion. [3] AAIB U K “ident ified 153 reports of smoke/fumes in add ition to the investigate d incident on UK fleet over a thr ee-ye ar period , includ ing 4 0 reports whe re exposu re had “ad verse physiolo gical effect s on on e or both p ilots, in so me cases severe .” [4 ] SUST Switzerland “ Hydraulic flu ids , as they ar e used today in co mmer cial aviation, fundam entally pose a non - negligib le risk potential ” [5] [translated] • “The kno wn repor ted serious incide nts (involving im pairmen t or incapacitatio n of crews) ar e rare a nd the saf ety an alysis ob jective f or such h azardou s event is not put into que stion ” • ”The Agency is not aware of any accident (involving injuries or loss of life o r substant ial aircraft damage) for which cabin air conta mination by en gine or APU has been identifie d as the root ca use.” • “Health issues ar e not within the p rimary sco pe of the Agency’ s mandate . However , the Agency would take action whenever a health case is evide nced by compe tent health author ities which would r equire a chan ge in the design o f aircraft.” • “The po tential safety risk can be mitigated b y existing procedu res and equ ipment (including the use of oxygen m asks )” Departmen t of Mecha nical En ginee ring, Ce ntre f or Ind ustrial Man age ment 5 EAS A ’ s interpretation of r isk [9] Safety engi neeri ng ph iloso phy Inte rpre tati on 6 Presentation progress Departmen t of Mecha nical En ginee ring, Ce ntre f or Ind ustrial Mana ge ment Flight safety - final reports Recommendations Regulations 7 UK final report recom mendation Departmen t of Mechanica l Engin eering, Centre f or Indu strial Manag ement Safety Recommendatio n 2007- 002 (to EA SA) and 2007 - 003 (t o F AA) “It is recommended that the EASA consider req uirin g, for all large aerop lanes operating for the purposes of commercial air transport, a system to enable the flight crew to identify rapidl y the source of smoke by providing a flight deck war ning of sm oke or oil m ist in the air deli vered from each air conditio ning uni t.” [4] Safety Recommendatio n SE/SUB/LF/10/2016 “The installatio n of technical moni tori ng capabili ties such as senso rs that routinel y record the composition or possi ble contami nation of the cabin air in the aircraft in rea l time and wa rn the pilots in du e time, coupled with suitable filter systems, sh ou ld be mandato ry fo r ai rcraft th at u se bl eed air from the engines for the cabin air .” [6] [ translated] Departmen t of Mechan ical Eng inee ring, Cen tre fo r Indu strial Manag emen t 8 Austria final report r ecommendation REGUL A TI ON (EC) No 21 6/20 08: “Results of air accide nt investigation s should be acted upo n as a matter of urgency , in particular whe n they relate to defective aircraft design and/or operation al matters, in order to ensure consumer confid ence in air transpo rt.” [7] UK AAI B in r elatio n t o 2007 - 002 : “T o date, the AAIB has not received formal response s to these recommenda tions.” [4] Departmen t of Mecha nical En gine ering, Centre for In dust rial Manag ement 9 Recommendation follow - up Safety philosophy Interp retati on Flight safety - final reports Recommendations Regulations Departmen t of Mechanica l Engin eering, Centre f or Indu strial Manag ement 10 Presentation progress CS 25.1309(c) requ ires that “ inform ation c oncer ning unsa fe s ys tem opera ting condi tions must be provi ded to th e crew t o enabl e t hem to take appropriate co rrective action . Compliance wi th this requiremen t includ es considera tion of crew alerting cue s, corrective action required , and the capabil ity of detecting faults.” [8 ] 11 EAS A CS 25.1309(c) - W arning Indication Departmen t of Mecha nical En ginee ring, Ce ntre fo r Ind ustrial Mana geme nt • “The required informatio n will depend on the de gre e of ur genc y for recogni tion and corrective actio n by the crew . It should be in the form of : • a warning , if im m ediat e r ec ognition and c orr ec tive or c ompe nsa tor y actio n b y th e crew is req ui red ; • a caut ion if immedi ate crew awaren ess is required and subsequ ent crew action wil l be requi red; • an advi sory , if crew aw areness i s req uired and su bsequ ent crew acti on may be require d; • a message in the other cases.” [8] 12 EAS A CS 25.1309(c) - W arning Indication Departmen t of Mechan ical Eng ineering , Cent re for In dust rial Manage ment “Some example s include reconfigurin g a system, being aware of a r educ tion in saf ety ma rgins , chang ing th e fl ig ht plan o r regi me, or making an unsche duled la nding to re duce e xposur e t o a mor e se ve re Fa ilure Con di ti on that would result from subsequent failure s or operational or environ mental condi tions. Inform ation is also r equir ed if a fa ilure m ust be corrected before a subsequent fli ght.” [8 ] 13 EAS A CS 25.1309(c) - W arning Indication Departmen t of Mecha nical En gine ering, Centre f or Ind ustrial Man age ment “Some example s include reconfigurin g a system, being aware of a r educ tion in saf ety ma rgins , chang ing th e fl ig ht plan o r regi me, or making an unsche duled la nding to re duce e xposur e t o a mor e se ve re Fa ilure Con di ti on that would result from subsequent failure s or operational or environ mental condi tions. Inform ation is als o requir ed if a fa ilure m ust be corrected befo re a sub sequen t f lig ht .” [8 ] “period ic maintenan ce or flight crew checks should not be used in lieu of detectors.” [8] 14 Departmen t of Mecha nical En gine ering, Centre f or Ind ustrial Man age ment EAS A CS 25.1309(c) - W arning Indication 15 EAS A definition unsafe condition Departmen t of Mecha nical En gine ering, Centre for In dust rial Manag ement An unsafe conditio n exists if there is factual evidence (from service experi ence, analysi s or tests) that: (a) An event may occur that would result in fatalitie s, usually with the loss of the aircraft, or reduce the capabili ty of t he aircraft or the ability of the crew to cope with adverse op erating condi tions to the extent t hat there would be: • A l a r g e r e d u c t i o n i n s a f e t y m a r g i n s o r f u n c t i o n a l c a p a b i l i t i e s • Physical distres s or exces sive workload such that the flight crew cannot be re lied upon to pe rfor m the ir t ask s ac cur ate ly or c omple tely ” [8] Safety philo sophy Inte rpre tatio n Flight safety - final reports Recommendations Regulations Departmen t of Mechanica l Engin eering, Centre fo r Indu strial Manag ement 16 Presentation structure Departmen t of Mechanica l Engin eering, Centre f or Indu strial Manag ement 17 Failure probability versus severity [8] • Not for design features that have been show n to negatively af fect safety . CS 25. 1309( a) • Systems should perform as intended under all f oreseeable operating conditions and shou ld not pose a dange r in themsel ves. CS 25. 1309( a) • Ef fect s of failure probab ility , not acciden t probabili ty 18 Functional Hazard Assessment Departmen t of Mechanica l Engin eering, Centre f or Indu strial Manag ement Safety targets without system architecture Aim preli minary functiona l hazard assessme nt [10 ] • safety objectives of the system relative to the identifie d functional failu re modes • not cons ider t he sy ste m archit ecture • conside r the worst c ase effects 19 A viation safety explained - FHA Departmen t of Me chanical E ngine ering, Ce ntre fo r Indust rial Manage ment “The followi ng factors should be consi dered (and appropria tely declared if used) when determi ning the severi ty of a failure cond ition: • time to detection (i.e. when detected); • failure recogni tion provid ed (i.e. how detected) • how would the pilot react (i.e. what to do) to cope with the failure and the timeline ss thereof” [10 ] 20 FHA philosophy Departmen t of Mecha nical En gine ering, Centre for In dust rial Manag ement • “ The known reported serio us incidents (invo lving impair ment or in capacitation of crews) ar e rare a nd the safety ana lysis objective for such hazardous e vent is not put into question” • ”The Agency is not aware of a ny accident (invo lving injuries o r loss of life or substantial aircr aft damag e) for which cabin air conta mination by en gine or APU has been identified a s the root cause .” • “ “Health issues ar e not within the p rimar y scope of the Agency’ s mandate. Howe ver , the Agency would take action whenever a health case is evid enced by comp etent health author ities which would r equire a cha nge in the desig n of aircra ft.” • “The po tential safety risk can be mitigated by existing proce dures and e quipment (including the use of oxygen m asks)” Departmen t of Mechanica l Engin eering, Centre f or Indu strial Manag ement 21 EAS A ’ s interpretation of r isk [9] 22 Risk in safety engineering Departmen t of Mechanica l Engin eering, Centre f or Indu strial Manag ement RISK = probability x sever ity x detection 23 Risk in safety engineering Departmen t of Mechanica l Engin eering, Centre f or Indu strial Manag ement RISK = probability x sever ity x detection Crew = detection & system operator • “When assessing the consequence s of a given failure condi tion, account should be taken of the warnings given, the comple xity of t he crew action. [10] • Pilots and cabi n crews should form an integral part of such discussions as many Safety Assessors have little to no operatio nal experi ence.” [10] • “Extensive service exp erience al one showi ng that the failure conditio n has not yet occurred is not suf ficient reason to indi cate that a single failure cond ition cannot exist.” [10 ] 24 FHA philosophy Departmen t of Mecha nical En gine ering, Centre for In dustrial Man age ment 25 References used Departmen t of Mechanica l Engin eering, Centre f or Indu strial Manag ement 1. Adriaensen , A., ‘Fragm entation of Infor mation’ in In ternation al Data Gat hering fr om Aircraft Fu me Events in Co nference Proceeding s, Sessions pre sented a t the 201 7 Inter national Ai rcraft Ca bin Air Conferen ce 19- 20 September 2017. J Health Pollu tion , 20 19. 9 (24): p. 4 - 11 . 2. CAA, UK, CAA Mandator y Occurren ce Report ing (MOR) - Engine Oil F ume Events – UK AOC Aircraft . 201 1. p. 91. 3. AAIB, Re port on the Incide nt to BAe 146 G-JEAK during th e descen t on Birmingh am airpo rt on 5 November 2000 . 2004, Air Accidents Invest igation Bran ch, Depart ment for T ranspo rt, United King dom: UK. 4. AAIB, AAI B Bulle tin: 4/ 200 7, EW/ C200 5/0 8/1 0, Bomb ard ier DHC -8- 400, G -JECE . 200 7, Air Accidents Inve stigation Bran ch, Departm ent for T ranspo rt, United King dom: UK. 5. SUST , Summ arischer Bericht HB -JHC, 2 6.1 1.2015 . 2016, Schweizerische Sicherheitsu ntersuch ungsstelle. 6. VERSA, Unte rsuchung sbericht Schwere St öru ng Mit Dem L uftfahrze ug der T ype Bombardier DHC-8- 402 am 06.05.2015 um ca. 10:5 4 Uhr UT C im Gemeindegebiet von Schwech at sowie Bezirk Wien - Umgebu ng . 2016, V er kehrssicherh eitsarbeit für Österre ich. 7. EU, REGULA TION (EC) No 216 /2008 OF THE EUROPE AN P ARLIAMENT AND OF THE COUNCIL of 20 Feb ruary 2008 on common rules in th e field of civil aviat ion and e stablishing a European Aviatio n Safety A gency . 2008, Europe an Union. 8. EASA, Cert ification Specification s for Lar ge Aero plan es CS - 25, amendment 22 . 2018. 9. Kritzinger , D., Aircraft syste m safety: a ssessments fo r initial airwor thiness cert ification . 201 7: Elsevier , Wo odhead Publishing 10. EASA, CRD 2 009 - 10: Comme nt Response Document (CRD) T o Advance Notice Of Proposed Amendment ( A- Npa ) 2009 - 10 "Cabin Air Quality Onbo ard La rge Aero pla nes " . 20 1 1. Contact: [email protected] Departmen t of Mechanica l Engin eering, Centre f or Indu strial Manag ement 26 Aircraft Cabin Air Inte rn ational C onfe rence 20 21 (ACA 2021) – Pro ceedings Conference : Online, 1 5 - 18 March 20 21 Conference Di rector: Tristan Loraine Publisher: Lon don, UK: GCAQE (https://gcaq e.org) Editors: Dieter S cholz , Susan Michaelis How to ci te this paper (ISO 690, Harvard): AIRALDI, Alessandra , 20 2 1. Flig ht Sa fety and the K ey R ole of F lig ht A ttendants . A irc raft Ca bin A ir Inter nationa l Conference 2021 (On line, 15 - 18 March 2021) . London, UK: GCAQE. Ava ilable from: https://doi .org/10.5281/ zenodo.494578 8 Relat ed pres entat ion : https ://doi.org/10.528 1/zenod o.4730403 Revie w proc ess: Editorial review . The corresp onding author is m arked with *. 1 Flight Safety and the Key Rol e of Flig ht Attendants AIRALDI , Alessandra 1* 1 Global C abin A ir Quality Execu tive Lt d , London, U K E-M ail : airald ia@me. com Copyrig ht © 20 21 by author This w ork is licensed unde r the Crea tive Com mons Attribution 4.0 Internation al License ( CC BY ). http s :// creativ ecomm ons . org / licenses / by /4.0 Ab str ac t A cab in cr ew me mber r eport s on the key role o f fligh t att end ant s in fligh t sa fety ma nag ement. Keywords cabin , safet y, ca bin crew, fu me ev ent , con tan iman t The Cabin Sa fety secti on of the I nternational C ivil A v iation Organization w ebsite says, “C abin safe ty contribut es to t he preve ntion of accide nts and incide nts; the protec tion of the airc raft’s oc cupants, thro ug h proacti ve safe ty manage - me nt, includi ng hazard ide ntifica tion and safe ty risk manage ment; a nd the incre ase of survival in th e even t o f an emergency s ituat ion. ” ( ICA O 2021 ). Cab in crew m emb ers are q ual ified s taff wh o p lay a n imp ort ant pro acti ve ro le in ma nag ing sa fety b efore p ass enger s boarding , duri ng the f light an d afte r disem barking , cabin c rew are pr imari ly foc used on the pr eventi on of acc idents . The safety role of the cabin c rew is voluntarily not always blatant because a key part of our job involves the so calle d “E motio nal lab or”, in fe w wor ds we ne ed t o be a bl e to man age ou r f eeli ngs and ou r expr es sio ns when we work , es pe- cially d uring in teraction s with cust omers and co - work ers . Th is i s p art o f our trai nin g on crowd mana gemen t for exa m- ple. When we w elcom e ou r c us tomers , we ar e trai n ed to immed iat ely s tar t to ev alu ate t heir beha vio r esp ecial ly of those sit ting in the e mergen c y rows , beca us e we alway s need to b e prep ared for a su dden s afet y occ urren ce whic h may ne ed passeng ers he lp or preve nting unlaw ful i nterf erenc e and ma naging pas senge r eve nts that c an co mpromi se safety a nd s ecurity of th e flight, su ch as hijackin gs. Cabin c rew role is not only ke y to pre venting incide nts from esca- lating in the cab in but it includes also being a ble to adequately in form the flight crew of abn ormal situ ations o bserved in the c abin or re lating to the aircr aft, such a s pressur izatio n probl ems or en gine a no mali es. In 201 9 during their annual confe rence presenta tion, ICAO r ecommende d some key public ations to stake holder s with th e aim to highligh t some poss ible sa fety threats and errors , risk scena rios and a ircraft accidents also affectin g th e cabin crew’s safety area o f competence, one of this is th e Circular 344 titl ed Guid elines on Ed ucatio n, Training an d Reportin g Practices rela ted to Fume Even ts, publ ished back in 2015 ( ICAO 2015 ) . The fl ig ht sa fety imp lica tion s o f crew memb ers' ex pos ure to oil f umes source d to the a ircraft air suppl y system , are pr oven to be highl y danger ous that’s why the IC AO h as dev elop ed g uid ance ma t erial to i mpr ove a war enes s an d t rain ing o f a ll cre w, rel at ed to the man - agem ent o f fu me ev ents . At a ny a irlin e level in f act any defi ciencie s and/or unse rvice a bili ty of saf ety equi pment or Flight S afety a nd the Key Role of Fl ight Attendants 2 sy st ems mu st alwa ys be repo rted to en ab le ap prop riat e mand at ory repo rti ng to b e made. It is i n the i nter ests o f sa fe- ty to ensur e the full , fre e and uni nhibite d repo rting o f all incide nts t hat a ffect fli ght safet y . When it c omes t o rep ort a fu me ev en t, es p eciall y wh en th er e is n o s tro ng s mell o r no clear smo ke in the ca bi n it is alwa ys very diffi cu lt t o fi le a r epo rt. In s ome air lines ca bin cr ew ca nn ot d irect ly r ep ort fu me ev ent s, even if t hey mi ght be syste mic fail ing w hich c ould easi ly re sult i n a r epe ated e vent. T hese kind of eve nts th at sho uld be addre ssed w it h pri orit y h ave s omet im es to fo llo w a ver y comp lica t ed pr oc edu re whi ch imp li es th at the ca bin crew firs t sp eak to t he c omman der wh o must the n contact the he ad of p il ots to s eek ver ification that it is a “re d flag ” event and then only if this is conf irm ed the cabin c re w c an repo rt the i ssue with such a pri ority. M ost f ume eve nts that are contaminate d air smell with no v is ibl e fumes then fin ish to be a lmos t n ever repo rted - probably this hap pens 99 % of the ti mes. ICAO Guidelines on E ducat ion, Training a nd Reportin g Practices related to Fume Even ts would recommend that all the crew is trained to re cognize, c haracteri ze, respond to, and r epo rt f ume events, w ithout any obstacl e, but not ever y airl ine has a spe cif ic tr aining for c abin crew , nor sui table protec tive personal equipm ents. In my lon g ca reer no w I h ave un for tun atel y en cou nter ed m an y crew wh os e hea lth was a ffe ct ed as a r esu lt of e xp o- sure to t hese c ontam inants in the avi ation e nvironm ent. Some of them have de veloped chroni c bre athing dif fic ulties and cogni tive impai rme nt, which i nclude the i nabilit y to carr y out routi ne task s: skil ls y ou don’t wa nt any pe rson t o lose, es pecially a ny cr ew me mber. There is ext ens ive s cien tific liter atu re on th e toxico logic al co ns equ ences of rep eat ed lo w dos e exp os ure to ch emi- cals. T he he alth of cabi n crew, pilo ts and passe nger s has to be put am ong the priori tie s, espec iall y now w here the Aviation has to be redesigned to face the pos t pan demic. O n existi ng bleed air architectu re air craft, fugitiv e em issio ns from a ircra ft engi nes MUS T b e redu ced t o th e min imu m ac hi evab le u sin g Bes t Av aila ble Tec hno log y (B AT). On futu re generation s of aircr aft all th e air lines should be united t o c hoose a ble ed - free arc hit ect ure List of Refer ences INTERNA TIONAL CIV IL AVIA TION O RG ANIZATION , 20 1 5 . Cir 344 - AN/202 : Guideli nes on Educati on, Trai ning and Re portin g Prac tice s relate d to Fum e Eve nts . Availa ble from: https:// perma. cc/PMX 5 - PPY 7 [viewe d 2021 - 06 - 12] . INTERNA TIONAL CIVIL AVIA TION ORG ANIZAT ION, 2021 . Cabin Safety. Availa ble from : https://ww w.icao.int/safety/AirNavigation/OPS /CabinSafety/P ages/default.aspx [ view ed 2021 - 06 - 12 ]. About t he Au thor Alessa ndra Air aldi i s a c abin cre w me mber, spe cial ized i n the ar ea of OH&S w ith he r union and at a re gi onal le vel, a nd one of the boar d memb ers of th e GCAQE , th e glo bal coal i tion of h ealt h an d sa fety a dvo cates commi tt ed t o ra isi ng awareness and finding s olut ions to p oor air qua lity on commercia l aircra ft. FLIGHT SAFETY AND THE KEY ROLE OF FLIGHT ATTENDANTS By Ales sandra Ai raldi 1 Very go od afternoo n to one and all present here and thank you ag ain for joining us today on t he 20 21 Aircraft Cabin Air Co nfe ren ce. 2 My name is Alessandra Air aldi, I am a Cabin cr ew member, speci alize d in the area of OH&S w ith my union and at a regional leve l and I’m on e of the board member s of the GCAQE, the global coalit ion of health and safety avoc ates c ommitte d to raising aware ness and finding solutions to poor air quality on commerc ial ai rcr afts. Im here today to intr oduce you to the key role of the flight at tenda nts in the flight safety ma nagement. 3 Cabin crew members are q uali fied staff who play an important proactive role in managing safe ty: before p assengers boarding, during the flight and after disembarking. cabin crew are primarily focused on the prevention of acci dents. 4 The sa fety r ole of t he c abin crew is volunt arily n ot alw ays b latan t be cause a key part of our job involve s the so ca lled “Emo tio nal lab or”, in few w ords we need to be able t o manage our fe elings and our expr essions when w e work , espe cially du r i ng i nt e r a 5 Cabin crew role is not only k ey to p reve nting incidents from escalati ng in t he cabi n but it includes also being able to adequ ately i nfo rm th e flig ht crew of abno rm al situations observed in the ca bin or relating to the airc raft, such a s pressurization problems or engine ano malies. 6 In 2019 during the annual conf erence present atio n , ICAO recommended some ke y publica tions to stak eholder s with t he aim t o highlight some possible safet y thre ats a nd errors , ri sk scen arios and ai rcraf t accidents als o af fectin g the cabin crew’s safety area of com petence , one of this is the Circu lar 3 44 title d Guideli nes o n Educatio n, Tr aining and Reporting Practi ces related to F ume Events, publ ished back in 2015. 7 The fli ght sa fety i mpl ica ti ons of cr ew m embe rs expos ur e t o oil fum es sou rce d t o th e aircraf t air supply system, a re proven to be highly dangerous that’s why the ICAO has developed g uidance material to im prove aw areness and training of all crew , related to the manag ement o f fume events. At any ai rlin e level i n fact any deficiencies and/or unservic eability of saf ety equipment or system s must always b e reported to enable appropria te manda tory repo rting t o be made . 8 It is in the int erests of safety to ensu re th e full, f ree and uninhibited reporting of all incidents that affect flight safety. 9 Most fume events, that is contam inated air smell with no visibl e fume s then finish to be almost never reported - proba bly th is happens 99% of the times. 10 ICAO Gui del in es o n Education, Traini ng and Reporting Practices related to Fume E vents would recommen d that all the crew is trained to recogn ize, characterize, respond to, and report fume events, wit ho ut a ny o bst acl e, bu t not every airline has a specific training for cabin crew, nor suitable protective personal equipmen ts. 11 Thank you again for joining u s today & please do spread the word and fly informed. ALESSANDR A AIR ALDI GCAQ E Board Member https:/ /www.gca qe.or g Aviation OH&S Mobile : +3 9 3 35 42 823 4 e mai l: ai raldi a@me. com 12 a e r o s p a c e A r t i c l e O i l F u m e s , F l i g h t S a f e t y , a n d t h e N T S B J u d i t h A n d e r s o n 1, * a n d D i e t e r S c h o l z 2 C it at i o n : A n d e r s o n , J . ; S c h o l z , D . Oil F u m e s , Fli g h t S a f e t y , a n d t h e N T S B . A e r o s p a c e 2 0 2 1 , 8 , 3 8 9 . h tt p s : / / d oi . o r g / 1 0 . 3 3 9 0 / a e r o s p a c e 8 1 2 0 3 8 9 A c a d e mi c E dit o r : B o s k o R a s u o R e c ei v e d : 9 N o v e m b e r 2 0 2 1 A c c e pt e d : 2 D e c e m b e r 2 0 2 1 P u bli s h e d : 1 0 D e c e m b e r 2 0 2 1 P u b l i s h e r ’ s N o t e : M D P I s t a y s n e ut r al wit h r e g a r d t o j u ri s di c ti o n al cl ai m s i n p u bl i s h e d m a p s a n d i n s tit uti o n al a f fil- i a t i o n s . C o p y r i g h t : © 2 0 2 1 b y t h e a ut h o r s . Li c e n s e e M D P I , B a s el , S wit z e rl a n d . T hi s a rti cl e i s a n o p e n a c c e s s a r ti cl e di st r i b u t e d u n d e r t h e t e r m s a n d c o n di t i o n s o f t h e C r e ati v e C o m m o n s A tt ri b u t i o n ( C C B Y ) li c e n s e ( h t t p s : / / c r e a ti v e c o m m o n s . o r g /li c e n s e s / b y / 4 . 0 / ) . 1 D e p a rt m e n t o f Ai r S a f e t y , H e al t h & S e c u r i t y , A s s o ci a ti o n o f Fl i g h t At t e n d a n t s - C W A A F L - C I O , 5 0 1 3 r d S t . N . W . , W a s hi n g t o n , D C 2 0 0 0 1 , U S A 2 Ai r c r a f t D e si g n a n d S y s t e m s G r o u p ( A E R O ) , H a m b u r g U ni v e r si t y o f A p pli e d S c i e n c e s , B e rli n e r T o r 9 , 2 0 0 9 9 H a m b u r g , G e r m a n y ; i n f o @ P r o f S c h ol z . d e * C o r r e s p o n d e n c e : j u di t h @ a f a n e t . o r g A b s t r a c t : D u ri n g i t s i n v e s ti g a ti o n s i n t o a s e r i e s o f t e n ai r c r a f t c r a s h e s f r o m 1 9 7 9 t o 1 9 8 1 , U S N a ti o n al Tr a n s p o r t a ti o n S a f et y B o a r d ( N T S B ) o f fi c i al s w e r e p r e s e n t e d wi t h a h y p o t h e si s t h a t “ s e v e r a l ” o f t h e c r a s h e s c o ul d h a v e b e e n c a u s e d b y pil o t i m p ai r m e n t f r o m b r e at hi n g oil f u m e s i n fli g h t . T h e N T S B a n d t h ei r i n d u s t r y p a r t n e r s ul t i m a t el y di s mi s s e d t h e h y p o t h e si s . T h e a u t h o r s r e vi e w e d t h e c r a s h r e p o r t s , t h e m e c h a ni c s o f t h e r el e v a n t e n gi n e oil s e al s , a n d s o m e e n gi n e bl e e d ai r d a t a t o c o n si d e r w h e t h e r t h e di s mi s s al w a s j u s ti fi e d . F o u r o f t h e ni n e ai r c r a f t c r a s h r e p o r t s i n cl u d e d e t ail s w hi c h a r e c o n si s t e n t wit h pi l o t i m p ai r m e n t c a u s e d b y b r e a t hi n g oil f u m e s . N o n e o f t h e t e s t s o f g r o u n d - b a s e d bl e e d ai r m e a s u r e m e n t s o f a s u b s e t o f oil - b a s e d c o n t a mi n a n t s g e n e r a t e d i n t h e e n gi n e t y p e o n t h e c r a s h e d ai r c r a f t r e p r o d u c e d t h e i n fli g h t c o n di t i o n s t h a t t h e a c c i d e n t i n v e s t i g a t o r s h a d fl a g g e d a s p o t e nti all y u n s a f e . T h e N T S B’ s c o n cl u si o n t h a t t h e h y p o t h e si s o f pil o t i n c a p a ci t a ti o n w a s “ c o m pl et el y wit h o u t v ali di t y ” w a s i n c o n si s t e n t wi t h t h e e vi d e n c e . P a r ti e s wi t h a c o m m e r ci al c o n fli c t o f i n t e r e s t s h o ul d n o t h a v e pl a y e d a r ol e i n t h e i n v e s ti g a t i o n o f t h ei r p r o d u c t s . T h e r e i s e n o u g h e v i d e n c e t h a t pi l o t s c a n b e i m p ai r e d b y i n h ali n g oil f u m e s t o m o ti v a t e m o r e s t r i n g e n t d e si g n , o p e r a ti o n , a n d r e p o r ti n g r e g ul a t i o n s t o p r o t e c t s a f e t y o f fli g h t . K e y w o r d s : ai r c r a f t ; a c ci d e n t ; fli g h t s a f e t y ; f u m e s ; e n gi n e oil ; h y d r a uli c fl ui d 1 . I n t r o d u c t i o n W i t h t h e e x c e p ti o n o f t h e B o ei n g 7 8 7 , c o m m e r ci al a n d mi li t a r y ai r c r a f t a r e d e si g n e d t o “ bl e e d ” ( o r e x t r a c t ) v e n til a ti o n ai r , ei t h e r o f f t h e m ai n ai r c r a f t e n gi n e c o m p r e s s o r s o r f r o m a n a u xil i a r y c o m p r e s s o r w h e n t h e ai r c r a f t i s o n t h e g r o u n d . T hi s h o t c o m p r e s s e d “ bl e e d ai r ” i s t h e n c o ol e d , d e h u mi di fi e d , t y pi c all y mi x e d w i t h s o m e f r a cti o n o f r e ci r c u l a t e d ai r , a n d r o u t e d t o t h e c a bi n a n d fli g h t d e c k f o r v e n ti l a t i o n a n d p r e s s u ri z a ti o n [ 1 ] . T o g r e a t e r o r l e s s e r d e g r e e s — e n gi n e oi l c a n c o n t a mi n a t e t h e c o m p r e s s e d ai r , w h e t h e r i t m i g r a t e s a c r o s s e n gi n e s e al s , s pill s f r o m a n o v e r s e r vi c e d r e s e r v oi r , o r i s v e n t e d i m p r o p e rl y , f o r e x a m pl e [ 2 ] . T h e p r o bl e m wi t h t h i s d e si g n i s t h a t a f r a cti o n o f t h a t c o m p r e s s e d ai r i s t h e n bl e d o f f t h e e n gi n e a n d r o u t e d t o t h e ai r c o n di t i o ni n g s y s t e m f o r c a b i n v e n ti l a ti o n a n d p r e s s u ri z a ti o n . T h e “ bl e e d ai r ” s t r e a m i s n o t fil t e r e d , s o o il f u m e s f r o m t h e e n gi n e c a n b e d eli v e r e d di r e c tl y t o t h e o c c u pi e d z o n e s o f t h e ai r c r a f t . C o n c e r n s a b o u t ai r c r e w e x p o s u r e t o eit h e r s u s p e c t e d o r c o n fi r m e d bl e e d - s o u r c e d f u m e s i n fli g h t h a v e b e e n r ai s e d gl o b all y si n c e t h e 1 9 3 0 s o n al l t y p e s o f ai r c r a f t [ 3 – 1 3 ] . O n e o f t h e e a rl y r e f e r e n c e s t o pil o t s b r e a t hi n g “ h o t oil f u m e s ” i n fli g h t a c k n o wl e d g e d t h a t “ t h e s y m p t o m s i n t h e s e c a s e s h a v e b e e n si mi l a r t o t h o s e o f c a r b o n m o n o xi d e p oi s o ni n g , ” b u t n o t e d t h a t v a ri o u s al d e h y d e b r e a k d o w n p r o d u ct s a r e “ p r o b a bl y t h e c a u s a ti v e a g e n t s , ” w hi c h t h e a u t h o r d e s c ri b e s a s p r e s e n t a t c o n c e n t r a ti o n s t h a t a r e “ o b vi o u sl y s u f fi c i e n t t o b e d a n g e r o u s t o s a f e t y i n fli g h t ” [ 1 4 ] ( p p . 1 7 8 – 1 8 0 ) . W i t h i n t hi s hi s t o r y , t h e r e a r e t w o d o c u m e n t s w hi c h e x pli ci tl y r e f e r t o f a t al a c ci d e n t s a s s o c i a t e d w i t h pil o t i m p ai r m e n t c a u s e d b y oil - c o n t a mi n a t e d bl e e d ai r . O n e o f t h o s e d o c u m e n t s r e f e r s t o “ s e v e r al u n e x pl ai n e d f a t al c r a s h e s i n v ol vi n g si n gl e p a c k , c a r ri e r- b a s e d , A e r o s p a c e 2 0 2 1 , 8 , 3 8 9 . h tt p s : / / d oi . o r g / 1 0 . 3 3 9 0 / a e r o s p a c e 8 1 2 0 3 8 9 h tt p s : / / w w w . m d pi . c o m / j o u r n al / a e r o s p a c e Aerospace 2021 , 8 , 389 2 of 20 turbine-power ed air craft . . . attributed (rightly or wr ongly) to contaminated engine bleed air” [ 15 ] (p. 1). In r esponse to those crashes, the United States (U.S.) Air For ce, Navy , and manufactur ers appar ently “initiated eff orts to resolve the contamination pr oblem” [ 15 ] (p. 1). The other document describes an investigation by the U.S. National T ransportation Safety Boar d (NTSB) conducted in r esponse to ten crashes on privately-operated turbo- pr op planes, all equipped with the Garrett TPE331 engine [ 16 ]. NTSB investigators had hypothesized that “several” of the crashes could have been the result of the pilots being impair ed by breathing oil fumes inflight. The suggested source of the oil fumes was a cracked fr ont main shaft compr essor carbon seal in the engine. In r esponse, the NTSB initiated gr ound-based engine testing to assess what the pilots may have inhaled [ 16 ]. In conjunction, the U.S. Federal A viation Administration (F AA) exposed test animals to oil fumes and observed the physiological ef fects [ 17 ]. Ultimately , the NTSB and their industry partners dismissed the hypothesis that inhaling oil fumes could have impair ed any of the pilots [ 16 ]. The authors reviewed the evidence to determine if the dismissal was supported by the evidence that was available at the time. The authors also r eviewed the r elevant aviation r egulations in the United States to consider whether they are suf ficient to pr event inflight exposur e to oil fumes. 2. Materials and Methods B e t w ee n A u gu s t 19 7 9 an d A p ri l 1 98 1 , t en p r i va t e ai r c ra f t, ea c h ou t fi t t ed w i th G a r r e t t T PE 3 3 1 en g in e s lu b r ic a te d w i th E x xo n 2 3 80 o i l, c r a sh e d. T he d a t es , l oc a t io n , ai r c ra f t ty p e s, a n d r e gi s tr a ti o n n um b er s a r e l i s te d i n T ab l e 1 , r e p r o d uc e d f r o m t he N T SB i n v es t ig a ti v e r e p o rt s [ 1 6 ]. T able 1. Accidents investigated for pilot incapacitation. Crash No. Date (yyyy-mm-dd) Location Aircraft T ype Registration No. 1 1979-08-03 Hays, Kansas Mitsubishi MU-2B N208MA 2 1979-11-01 Nashville, T ennessee Mitsubishi MU-2F N8730 3 1979-12-21 Pr ovo, Utah Mitsubishi MU-2B-20 N2-OBR 4 1980-01-11 Atlantic Ocean Cessna 441 N441NC 5 1980-02-14 Near Houston, T exas Mitsubishi MU_2B-35 N346MA 6 1980-02-23 New Orleans, Louisiana Mitsubishi MU-2-40 N962MA 7 1980-12-06 Ramsey , Minnesota Mitsubishi MU-2-40 N969MA 8 1980-12-15 Richmond, Indiana Mitsubishi MU-2B-30 N93UM 9 1981-01-07 Burns, Or egon Aero Commander 690B N81521 10 1981-04-22 Alpena, Michigan Mitsubishi MU-2B-20 N9JS The authors sear ched online NTSB databases for the crash r eports, nine of which wer e fatal accidents and one of which was a serious incident. The crash reports wer e only available on micr ofilm and, because of the COVID-19 pandemic, the NTSB library which houses micr ofilm r eports was closed. Instead, the authors were able to pur chase nine of the ten crash r eports thr ough a private company (General Micr ofilm, W est V ir ginia). The r emaining r eport was unavailable. Additional details of the 10 crashes are listed in T able 2 . The authors r esear ched the design of the Garr ett TPE331 engine and the associated potential for bearing and seal failur es which could cause oil fumes to contaminate the bleed air supply . The authors r eviewed the NTSB investigative report which described the r esults of bleed air quality engine testing for selected oil-based contaminants in the bleed air supplied by a Garr ett TPE331 engine with and without oil contamination [ 16 ]. The test pr otocol had been designed to “investigate the hypothesis that toxic or anesthetic gases could be generated fr om engine oil that leaked into the engine airflow thr ough a br oken seal and that these gases might adversely af fect the cr ew’s capacity to contr ol the air craft during critical phases of flight” [ 16 ] (p. 8). Key featur es of the bleed air tests ar e listed in T able 3 . Aerospace 2021 , 8 , 389 3 of 20 T able 2. Additional details of ten accidents investigated for pilot incapacitation. Crash No. NTSB Report No. Flight Phase, T ime of Day , W eather Pilot Age (Y ears), Flight T ime (h) Probable Causes/Factors (per NTSB) No. Deaths *** 1 ** MKC79F A046 cruise, night, “clear” 34; 2168. Forward main shaft bearing failed; improper inflight decisions; failed to obtain or maintain flying speed. 7 2 IAD80F A007 descent, night, three-mile visibility , dry , light fog PIC age redacted; 1498. Copilot age redacted; 2521 Pilot-in-command (PIC) misjudged the distance and altitude on final approach; inadequate supervision of flight; failed to use checklist. 5 3 DEN80F A012 approach, night, “visibility was around one mile” 46; 12,833 Inadequate pre-flight preparation or planning; improper Instr ument Flight Rules (IFR) operation; misjudged altitude; Pilot could not find runway; aircraft came to r est in water . 2 4 * IAD80AA018 descent, night, check 47; 8000 Miscellaneous, undetermined; unable to obtain a r esponse from cr ew; uncontrolled descent; aircraft came to r est in water . 3 5 FTW80F A042 approach, evening, two-mile visibility , rain showers 45; 12,500 Improper IFR operation; altimeter setting incorrect. 4 6 ** FTW80F A048 approach, morning, 0.25-mile visibility , fog 51; hrs. not reported Improper IFR operation; crashed into water . 7 7 ** CHI81F A010 approach, afternoon, “good” weather 54; 4949 Failed to obtain/maintain speed; icing conditions, including sleet, frozen rain, etc. 5 8 CHI81FEG03 approach, night, dense fog 59; 10,587 Improper IFR operation; icing conditions, including sleet, frozen rain, etc. 0 9 ** SEA81F A015 approach, afternoon, overcast, 15-mile visibility , wind calm 32; 2177 Miscellaneous/undetermined; uncontrolled collision with ground/water . 2 10 CHI81F A051 approach, night, two-mile visibility , light rain, fog 53; 16,766 Improper IFR operation; crash on final approach, 1.6 miles short of runway; cause unknown. 3 * Microfilm r eport was unavailable for crash #4. ** Details in the reports for crash #1, 6, 7, and 9 ar e consistent with engine oil fumes as a contributory factor . Additional details ar e provided in T able 5. *** In all but crash #8, everyone onboard was killed. In crash #8, the pilot and one of two passengers were injur ed. Aerospace 2021 , 8 , 389 4 of 20 T able 3. Key features of engine bleed testing, per the NTSB investigative r eport [ 16 ]. T est No. Carbon Seal Intact or Missing? Oil Added to Bleed Air? Glass Filter in Bleed Air Line? Reflects Potential Onboard Conditions? 1 intact No yes no 2 intact No yes no 3a–3f intact yes; 2–12 lb/hr yes no 3g intact No no no 4 intact No yes no 5a missing No yes no 5b missing yes; “dirty start” yes no The authors r eviewed the relevant aviation r egulations for U.S.-register ed aircraft operated on r outine commercial flights (T able 4 ). Globally , aviation r egulations ar e harmo- nized, so most of these regulations ar e the same in other countries. This is especially true for design and construction-r elated regulations which ar e classified under Part 25 of the Federal A viation Requirements in the United States and as CS-25 (Certification Standar ds) in Eur ope, published by the European Union A viation Safety Agency (EASA). T able 4. U.S. aviation regulations r elevant to air quality on routine commer cial flights. Regulation Design/Operation Description 14 CFR § 25.831(b) * “V entilation” Design “The aircraft air supply system must be designed to ensure that cr ew and passenger compartment air [is] free fr om harmful or hazardous concentrations of gases or vapors.” 14 CFR § 25.831(b)(1)“V entilation” Design The carbon monoxide concentration in the cabin and flight deck supply air must not exceed 50 ppm. 14 CFR § 25.1309(c) “Equipment, systems, and installation” Design “W arning information must be provided to alert the crew to unsafe system operating conditions, and to enable them to take appropriate corrective action. Systems, contr ols, and associated monitoring and warning means must be designed to minimize crew err ors which could create additional hazar ds.” 14 CFR § 121.703(a)(5) “Service difficulty reports” Operation Airlines “shall report the occurr ence or detection of each failur e, malfunction, or defect concerning . . . [a] aircraft component that causes accumulation or circulation of smoke, vapor , or toxic or noxious fumes in the cr ew compartment or passenger cabin during flight.” 14 CFR § 121.705“Mechanical interruption summary report” Operation Airlines shall report each “interr uption to a scheduled flight,” such as a diversion, cancellation, or tail swap, caused by known or suspected mechanical difficulties or malfunctions that are not r equired to be r eported under the 14 CFR § 121.703. F AA Order 8020.11D (Chapter 6 and F AA Form 8020-23) Operation Airlines shall report accidents and occurr ences which are associated with the operation of an aircraft and af fect (or could affect) the safety of operation, including smoke/fumes. * Note that “14 CFR” refers to the Code of Federal Regulations T itle 14 which ar e aviation and aerospace r egulations published by the F AA for U.S.-register ed aircraft. The symbol “§”is shorthand for “Part” when referring to U.S. regulations. The relevant r egulations include “Part 25” (Airworthiness Standards: T ransport Category Airplanes) and “Part 121” (Operating Requirements: Domestic, Flag, and Supplemental Operations). Aerospace 2021 , 8 , 389 5 of 20 Finally , the authors r eviewed some pr oposals to implement engineering and opera- tional contr ol measur es intended to pr event exposur e to oil fumes on air craft. 3. Results 3.1. Accident Reports For nine of the ten aircraft crashes, the authors wer e able to obtain the NTSB investi- gation r eports (T ables 1 and 2 ). The micr ofilm r eport for crash number 4 was unavailable. Of these nine crashes, eight were fatal accidents (35 people wer e killed) and one (crash number 8) was a serious incident (the pilot and one of the two passengers wer e injured). Details in the accident r eports for crash numbers 1, 6, 7, and 9 (T ables 1 and 2 ) suggest that oil fumes wer e either a contributory or casual factor (T able 5 ). T able 5. NTSB accident report details consistent with exposur e to oil fumes. Crash No. Description of Crash Conditions 1 The NTSB r eport describes how , when the pilot was en route, at what may have been top of climb, the pilot “reported a loss of oil pr essur e in the right engine.” At the same time, “the pilot reported smoke and fumes in the cabin.” A few minutes later , the pilot reported that he had shut down the right engine. He then stopped communicating with air traffic control and crashed into a field without putting the landing gear down (per witness reports). The subsequent tear down of the right engine “revealed that the forwar d main shaft bearing had failed.” 6 The NTSB report describes how , on approach, the pilot stopped r esponding to air traffic contr ol. The air craft descended into a lake and “all aboar d perished.” The report goes on to say that “[d]uring the course of the investigation, it was reported by various persons that the air craft had a history of smoke, fumes, and carbon monoxide collecting in the cockpit and cabin area...Examination of the interior of the subject aircraft envir onmental contr ol system r evealed an oily residue in the portion which is supplied by the left engine [with a history of a cracked carbon seal] while that supplied by the right engine was clean.” 7 The NTSB report describes how , on approach, the pilot did not r espond to air traffic contr ol instr uctions. W itness reports described how the air craft came out of the clouds spinning with the nose down and crashed into a field. In the engine tear down report, ther e were r efer ences to “black dirt deposits found throughout the entir e gas path of the engine . . . [including] the bleed air ports . . . ” The NTSB r eport stated that the pilot had failed to obtain/maintain speed and the cause of the crash was unknown. 9 The NTSB report describes how gr ound witnesses observed the aircraft flying away from the airport maneuvering erratically . The aircraft cr ossed a highway , pitched up steeply , fell, and crashed. The engine tear down was “to determine the condition of the carbon seal and bearing located between the compressor section and gearbox section.” The r eport concluded that “one carbon seal, due to the discoloring of the oil slinger , was leaking some oil past the face.“ The r eport also noted that “Bonneville Power maintenance personnel felt the amount of leakage was insignificant,” but the basis for their claim and their qualification to make it were not pr ovided. In addition to the four crashes described in T able 5 , crash numbers 5 and 10 (T ables 1 and 2 ) include details which could be r elated to oil fumes, although the sig- nificance of those details is less clear . Specifically , the NTSB r eport for crash number 5 describes how , without warning, the aircraft crashed into the tr ees near the runway on final appr oach. Another pilot who observed the crash stated: “W e feel that the pilot of the MU-2 got disoriented and just flew the airplane into the gr ound.” The autopsy r eport for the pilot r eported 5% carboxyhemoglobin in his blood. The NTSB r eport for crash number 10 describes how the aircraft crashed on final appr oach, after which the engine manufactur er performed the engine tear down to determine if oil fumes played a role in the crash. The manufactur er concluded that ther e was “no indication” of anything other than Aerospace 2021 , 8 , 389 6 of 20 normal engine operation and they attributed the engine compr essor carbon seal damage to impact. The Ci vil Aer omed ical I nstit ute (C AMI) t oxico logy l ab (the r esea r ch arm o f the F AA) test ed a com pone nt of the a ir sup ply sy stem f r om the a ir craft and f ound a “ trace q uant ity of petr oleu m base c onsti tuen t,” alt houg h the si gnifi canc e of tha t findi ng is no t clea r . 3.2. Description of the TPE331 Engine and Seal Assembly The Garr ett TPE331 is a fixed-shaft constant-speed turboprop engine (Figur e 1 ). Its gas turbine consists of a compr essor , combustion chamber , and turbine. Ambient air is directed to the compr essor section through the engine inlet. A two-stage centrifugal compr essor incr eases air pressur e and directs it to the combustion chamber . In the combustion chamber , fuel is added to the air through the fuel nozzles. On engine start-up, the gas mixtur e is ignited by igniter plugs. In a normal operation the igniter is not in use because the combustion is self-sustained. The hot and high-velocity combustion gases flow thr ough the turbine r otors, where the ener gy of the gases is converted to torque exerted on the main shaft (A in Figur e 1 ). The r eduction gear is designed as a planetary gear on the propeller shaft (B in Figur e 1 ). It converts the low tor que (at high rpm) of the main shaft to high tor que (at low rpm) on the propeller shaft and drives the pr opeller . The combustion gases leave the turbine to the atmospher e via the exhaust. Figure 1. Garrett TPE331 turbopr op engine (based on [ 18 ], p. 15-3). A. main shaft (engine shaft) with the gas turbine. B. propeller shaft with the r eduction gear . 1,2. bearings that support the main shaft. 3,4. bearings that support the pr opeller shaft. 1. compressor bearing. The TPE331 is called a fixed-shaft engine because the pr opeller is firmly connected to the gas turbine. The constant-speed engine maintains its speed by a governor on the pr opeller . The propeller shaft r otates at a constant speed of 1591 rpm in cruise flight. The main shaft of the engine rotates at a constant speed of 41,730 rpm. Power changes are made by incr easing the fuel flow (which increases the tor que) rather than the engine speed. Most of the air (70%) passing through the engine pr ovides internal cooling. Only about 10% of the air that passes thr ough the engine is actually used in the combustion pr ocess. Up to approximately 20% of the compr essed air may be bled off for the purpose of heating, cooling, cabin pr essurization, and pneumatic systems [ 18 ], which appears to Aerospace 2021 , 8 , 389 7 of 20 be within the average range for other engine types [ 2 ]. If the bleed air is contaminated with oil fumes, then the air in the cabin is also contaminated. Normal bleed air pr essur e is appr oximately 157 psi (10.82 bar) and the temperatur e is 360 ◦ C in cruise flight [ 16 ]. The engine shafts ar e supported by rolling bearings. The compr essor bearing (1 in Figur e 1 ) is a ball-bearing (Figur e 2 ). The same is tr ue for bearings 2 and 3 in Figur e 1 . Figure 2. A typical ball-bearing [ 19 ]. The engine cutaway drawing is given in Figur e 3 and a detail of that pictur e enlar ged is given in Figur e 4 . Figure 3. Garrett TPE331 turbopr op engine cutaway drawing [ 20 ]. In the TPE331 fr ont main shaft compr essor seal assembly , two seals ar e used, acting in series. They pr event the escape of the engine lubricant pr esent in the r eduction gearbox via the main shaft and thr ough the compr essor bearing into the compr essor (Figur e 4 ). The following detailed explanations ar e r epr oduced with text elements fr om [ 16 ]: “F i r s t , a me c h a n i c al ( c a r b o n ) se a l i s p r ov id e d to p r e v en t le a ka ge i f o pe ra t in g oi l p r es s u r es ex ce e d no rm al p r e s s ur e s a n d to p r e v en t po t en ti a l le ak a ge t ha t m ig ht o c cu r du r in g en g in e Aerospace 2021 , 8 , 389 8 of 20 sh ut do wn . Th e me ch an ic al s ea l po te nt ia ll y is s ub je ct t o we ar a nd d am ag e” [ 16 ] (p . 2) . “When the engine is shutdown, oil drains from the engine walls which incr eases the oil level above the shaft installation level of the compr essor front main shaft; without a mechanical seal, the oil would leak fr om the reduction gearbox, out the engine inlet and onto the gr ound. Ther efore, a mechanical (carbon-element) seal is necessary to pr event oil leakage when the engine is not operating” [ 16 ] (p. 33). This is illustrated in Figur e 5 . Figure 4. G a r r e t t T P E3 3 1 t u r b o p r o p e n gi n e c u t a w a y d r a w i n g ( d e t a i l b a se d o n [ 2 0 ] ) . A . m a i n sh a f t . B . f i r st - s t a g e c e n t ri f u g a l c o m p r e s s or . 1 . c o m pr e s s o r b e a r i n g ( a b al l - b e a r i ng ) . 2 . c a r b o n s ea l . 3 . l a b y r i nt h s e a l . Figure 5. Mechanical (carbon) seal assembly next to the main shaft compr essor bearing on the TPE331 engine (based on Figure 3 in [ 16 ]). “Secondly , the TPE331 has a pressurized knife-edge labyrinth air seal that is specifically designed to pr event passage of air/oil mist from the r eduction gearbox into the compressor chamber during engine operation” [ 16 ] (p. 2). “This pneumatic-type seal is pr essurized to appr oximately 26 psi (1.79 bar) at the inner knife edges. When the engine is operating, the pneumatic seal is independently capable of pr eventing the air/oil mist from passing out of the r eduction gearbox because of a flow of pressurizing air fr om the seal into the reduction gearbox. However , the labyrinth seal has no sealing capability to pr event engine oil from exiting the r eduction gearbox when the engine is not operating and, therefor e, requir es a mechanical seal to pr event oil leakage when the engine is shut down. The symptom of a failed mechanical seal is oil leaking past the labyrinth seal and running out the engine inlet onto the gr ound when the engine is not operating” [ 16 ] (p. 35). The bleed air passage dir ects sealing air from the compr essor to the labyrinth seal. All of this is illustrated in Figur e 6 and additional details are shown in Figur e 7 . Aerospace 2021 , 8 , 389 9 of 20 Figure 6. L a b y r i n t h s e a l c l o s e t o t h e m a i n s h a f t c o m p r e s s o r b e a r i n g ( b a s e d o n F i g u r e 1 1 i n [ 1 6 ] ) . N o t e : T h e c a r b o n s e a l i s l o c a t e d i n b e t w e e n t h e c o m p r e s s o r b e a r i n g ( o n t h e l e f t ) a n d t h e l a b y r i n t h s e a l ( o n t h e r i g h t ) i n t h e e m p t y s p a c e b u t i s n o t s h o w n i n t h i s f i g u r e . Figure 7. Flow through the labyrinth seal in the TPE331 engine next to the compr essor bearing and r esulting pressur e. The flow to the left pushes back the oil that still comes through the carbon seal (based on Figu re 13 in [ 16 ]). “The pr essure balances that ar e maintained may be clearly understood by considering that the chamber containing the air/oil mist operates at appr oximately 12 psia ( − 2 psig) while the center of the labyrinth is pr essurized to 26 psia (+12 psig). Since air will always flow fr om a higher pressur e area to a lower pr essure ar ea, air will flow outward fr om the center of the labyrinth. Each of the knife-edges operates with only slight clearance fr om the outer wall, resulting in a high local velocity as the air cr osses into the next chamber . W ith a high local velocity , the air/oil mist cannot flow past the knife edges and enter the compr essor air flow” [ 16 ] (p. 36). This is illustrated in Figur e 7 . “In addition to the labyrinth seal, ther e are two other pneumatic sealing actions incorporated in the oil containment design of the TPE331 engine . . . [First, ther e is] a negative pr essure of appr oximately 2 psi inside the r eduction gearbox with respect to atmospheric conditions. This is accomplished by pumping the oil out of the r eduction gearbox at a rate twice that at which it is being pumped in. (Nine gallons per minute in, versus 18 gallons per minute out.) The extra nine gallons pumped per minute is air and this cr eates a negative pressur e (slight vacuum) in the reduction gearbox. If the mechanical seal should fail, the overscavenging will draw air into the r eduction gearbox and will pr event the air/oil mist from flowing out . . . Secondly the negative pr essure ef fect is supplemented by raising the pr essure in the chamber on the air side of the mechanical seal to a positive six psi above ambient” [ 16 ] (p. 36). This higher pressur e is pr oduced by the centrifugal compr essor . Aerospace 2021 , 8 , 389 10 of 20 3.3. Bleed Air T esting In July 1981, the NTSB and a team of government and industry partners formed an “Ad Hoc Investigative Committee” to r espond to the hypothesis that oil fumes could con- taminate pilots’ br eathing air thr ough the main shaft compr essor carbon seal in the Garr ett TPE331 turbopr op engine. All the crashed air craft flew with this engine type. The team pr oposed to measur e selected gaseous contaminants (carbon monoxide, carbon dioxide, nitr ous oxides, and total hydr ocarbons) in the bleed air pr oduced by that engine type. The goal was to attempt to r epr oduce the conditions on the crashed air craft to determine whether the pilots could have been subjected to toxic or anesthetic gases suf ficient to impair their ability to operate the air craft. Because oil leakage thr ough the carbon seal was the suspected sour ce of oil fumes in the bleed air , selected gaseous contaminants were measur ed in the bleed air downstr eam of the compr essor , first thr ough an intact seal and second with the seal r emoved (consider ed worst-case), during conditions that ranged fr om no oil to 12 pounds of oil per hour (lb/hr). The sampling methods wer e developed by the Exxon Research and Engineering Company and the test conditions, summarized in T able 3 , were performed on an engine test stand at the Garr ett T urbine Engine Company . During two of the tests, oil mist samples wer e also collected and analyzed. Lar gely though, gases wer e sampled because the investigators “expected that particulate matter would not form” [ 16 ] (p. 9). 3.3.1. Primary Bleed Air T esting Conditions The key featur es of the 12 primary engine bleed testing conditions, as described in the NTSB r eport [ 16 ] ar e summarized in T able 3 . Additional salient details of the engine bleed testing ar e summarized in T able 6 . T able 6. Description of TPE331 engine bleed testing, per NTSB report [ 16 ]. T rial No. Description of Sampling Conditions 1–2 These two trials wer e intended to characterize backgr ound levels of contaminants in the bleed air str eam. The engine compr essor carbon seal was intact, and a glass wool filter was installed in the bleed line. Mor eover , oil was not purposefully injected into the bleed air stream. 3a–3f These six trials were intended to characterize levels of oil-based contaminants in the bleed air stream thr ough an intact engine compr essor carbon seal and a glass wool filter . Oil was injected into the bleed air str eam for 90 min at a rate of 2–12 pounds per hour while the bleed air was sampled for carbon monoxide, carbon dioxide, nitrous oxides, and hydr ocarbons. 3g This trial was intended to characterize levels of oil-based contaminants in the bleed air stream thr ough an intact engine compr essor carbon seal but without a glass wool filter in the bleed stream. The tester injected oil for 15 min, during which time the same gaseous bleed air measurements wer e made. 4 This trial was intended to simulate the potential for worst-case bleed air contamination by removing the engine compr essor carbon seal. Of note, though, a glass wool filter was installed in the sampling line and no oil was injected. 5a During this trial, the tester did not collect measurements but ran the engine fo r 10 min and then shut it down to prepar e for a “dirty start” in the following test. 5b During this trial, the engine underwent a simulated “dirty start” which involved internal oil ingestion. The tester measured the concentrations of carbon monoxide, carbon dioxide, nitrous oxides, and hydr ocarbons for the first 10 min after the engine was started. 3.3.2. Additional Engine Bleed Air T esting During two of the oil injection tests (3c and 3f), the tester collected oil mist samples on “membrane filters” which wer e subsequently analyzed for tricr esyl phosphates. The authors of the report noted that no “para or ortho isomers” of tricr esyl phosphate wer e Aerospace 2021 , 8 , 389 11 of 20 pr esent above the detection limit [ 16 ] (p. 24), although the authors did not define the detection limit or mention the concentrations of meta and mixed meta/para isomers which comprise mor e than 99% of commer cial blends [ 21 ]. During tests 1–3, carbon sorbent tubes and impingers wer e used to collect samples that wer e subsequently analyzed by GC-MS [ 16 ]. The authors stated that these “analyses performed by the Envir onmental Pr otection Agency (EP A) [lab] . . . did not lend themselves to meaningful interpr etation because of apparen t contamination of the samples and lack of parallel quantitation of known compounds . . . ” [ 16 ] (p. 27). Still, the authors af firmed that “based on the analyses, ther e was no significant toxicological gaseous content of the TPE331 engine bleed air . . . ” [ 16 ] (p. 27). The authors also r eferr ed to the pr esence of “a number of compounds in the bleed air under various conditions of the test pr otocol,” but described occupational exposur e limits as protective for workers. The r eport noted that, by comparison, “the concentration of those substances [measur ed by the EP A] appears to be at such a low level as to cause no acute degradation of pilot performance” [ 16 ] (p. 66). Specifically , the authors stated that “it is apparent that toxic ef fects to air craft cr ewmembers would only r esult fr om br eathing air contamination of suf ficient concentrations to cause acute ef fects” [ 16 ] (p. 66). 3.4. Regulations Air craft r egulations stipulate that the cabin and flight deck ventilation supply systems must be designed to pr ovide air that is “fr ee fr om harmful or hazar dous concentrations of gases and vapors” (14 CFR § 25.831(b)), which includes no mor e than 50 ppm of carbon monoxide and 5000 ppm of carbon dioxide (T able 4 ). Mor eover , cr ews must be pr ovided with “warning information” to alert them to unsafe conditions and enable them to take “appr opriate corr ective action” (14 CFR § 25.1309(c)) (T able 4 ). T o date, though, these r egulations have not been applied to monitor contaminants in the cabin air and alert pilots to the pr esence of oil fumes. In addition to the design r egulations, U.S. airlines ar e r equir ed to comply with thr ee F AA r eporting r egulations for fume events (T able 4 ), but all ar e underutilized [ 22 ]. 4. Discussion 4.1. Accident Reports In the investigated crashes (T able 1 ), eight of the ten aircraft wer e Mitsubishi MU-2 air - craft. The Mitsubishi MU-2 is a twin-engine turbopr op air craft with a pr essurized cabin (Figur e 8 ). The aircraft is known for its dif ficult handling and high rate of accidents, includ- ing fatal accidents [ 23 ]. Crash numbers 7 and 8 with this air craft wer e in icing conditions which may be r elevant, given an Australian Bureau of Air Safety Investigation r eport on two fatal crashes on MU-2 air craft, both of which were also in icing conditions [ 24 ]. However , even for the 1988 and 1990 fatal crashes in Australia, “icing on the airframe” was only listed as the “probable” cause and, for one of those two crashes, pilot fatigue was also r efer enced extensively . Thus, the refer ence to icing conditions in crash 7 in this investigation should be acknowledged but does not rule out cabin air contamination, either as a causal or contributory factor . Regar ding the r emaining two crashed air craft (T able 1 ), one was a Cessna 441 Conquest II and the other was an Aero Commander 690B. As with the MU-2, each of these is a turbopr op air craft with a pr essurized cabin. In a t l e a s t fo u r o f t h es e t e n c r as h e s , th e r e ar e d et a il s wh ich a r e co ns is ten t wi th i mp ai rme nt ca us ed by o il f um es ( T ab le 5 ). F or e ac h of t he c ra she s, t he NT SB i de nt if ied “ pr o ba bl e ca us es ” (i nc lud in g “u nd et erm in ed” ), a ll of w hi ch ar e r e pr od uc ed i n T abl e 2 . I n ma ny c as es, t ho ugh , th e “p r ob ab le c au se ” is mo r e of a d es cr ip ti on t han a n ex pl an at ion . Th e r ea l qu e st io n is, w hy ? Wh y di d the p il ot in c om ma nd “ mi sju dg e dis ta nce a nd a lti tu de” o r “f ai l to o bt ain /m ain ta in sp ee d”? W hy w as a ir t raf fi c co nt r ol “ un ab le to g et r e spo ns e fr om c r ew” ? W a s it b ec aus e th es e pi lo ts we r e di s tr ac ted o r fa tig ue d, or w er e t he y im pai r ed b y fum es? Aerospace 2021 , 8 , 389 12 of 20 Figure 8. Mitsubishi MU-2B (Photograph by Alan Lebeda [ 25 ], trimmed, GFDL 1.2). It i s te mp ti ng t o bl am e cr as he s on “ pi lo t er r o r ,” t yp ic al ly a tt ri bu te d to e it he r to i ne xp er i- en ce o r fa ti gu e. R eg ar d in g in ex pe ri en ce , th e fl ig ht t im e fo r th e pi lo ts o n th e cr as he d pl an es ra ng ed f r o m 14 98 t o 16 ,7 66 h ( av er ag e 79 99 ) (T ab le 2 ). On e an al ys is e st im at ed t ha t, d ur in g th e ti me o f th es e cr as he s, t ur bo pr op p il ot s lo gg ed a n av er ag e fl ig ht ti me o f 52 8 h pe r ye ar [ 26 ], s o if t he p il ot s on t he c ra sh ed p la ne s r efl ec t th is a ve ra ge , th ey ar e no t no vi ce s. Re ga r di ng f at ig ue , th e ac ci de nt r ep or ts d id n ot c on si st en tl y ci te e it he r ea ch p il ot ’s t ot al f li gh t ti me s pe ci fi c to th e ai r c ra ft t yp e th ey cr a sh ed or t he n um be r of h ou rs t he y fl ew d ur in g th e 24 h p ri or t o th e ac ci de nt f li gh ts . As a r esu lt , th e im pa ct o f pi lo t fa ti gu e ca nn ot b e as se ss ed . The authors of this paper ar e unaware of other challenges to the basis for the claims in the NTSB report [ 16 ] that it is not possible for oil fumes to either have contaminated the bleed air on these air craft or to have played any role in any of these accidents. Theirs is not the first r eport, however , to either overlook or downplay the flight safety implications of br eathing oil or hydraulic fluid fumes. For example, one published case study investigated the findings of six documented fume event investigations and identified specific oversights and misconceptions about the potential for oil to contaminate the bleed air , as well as a tendency to dismiss the crew-r eported symptoms as str ess r eactions [ 27 ]. Another investigation described an event during which pilots reported a blue haze shortly after r eaching cruise altitude, prompting a pr ecautionary landing [ 28 ]. The initial gr ound-based engine runs failed to identify any fault. Only additional (and non-standar d) high-power engine runs identified the source of fumes—a fractur ed bearing seal in the compr essor . This is important because high-power runs wer e not part of the fault-finding pr ocedure endorsed by the air craft manufacturer . Another investigation described how both pilots r eported fumes during approach and felt dizzy and nauseous, with irritated eyes and throat [ 29 ]. The pilots donned oxygen and r equested priority landing clearance. The auxiliary power unit (APU) was not operating during the appr oach phase, so it was not investigated as a potential source of oil contami- nation. However , the aircraft manufactur er has published bulletins alerting airlines that, when the APU is in use, oil fumes can contaminate the downstr eam environmental contr ol system and ducting, and fumes fr om that initial contamination can continue to manifest inflight, even when the APU is not in use [ 30 ]. Still, the APU was not checked, and the investigation was inconclusive; “no explanation” for either the fumes or the symptoms was found. In 2020, the Fr ench Bureau of Enquiry and Analysis for Civil A viation Safety (BEA) investigated a serious incident on a commer cial flight during which the pilots reported a str ong, acrid odor accompanied by irritant symptoms during taxi, shortly after the APU had been turned on [ 31 ]. During the climb out, both pilots reported dizziness, among other symptoms. They eventually donned oxygen masks and diverted to the near est airport. Aerospace 2021 , 8 , 389 13 of 20 Although the details ar e consistent with breathing bleed-sour ced oil fumes, maintenance inspections did not identify an obvious mechanical failur e. As a r esult, the accident investigator concluded that the incident—including fumes, persistent symptoms, and a diversion—was most likely caused by the pilots inhaling “an excessive quantity of carbon monoxide.” Failing to find a mor e plausible explanation, the accident investigators hypothesized that the sour ce of the fumes may have been engine exhaust from a small business jet as it taxied about 80 m away fr om the incident aircraft in the pr esence of a “calm wind.” However , the r eport added that it “cannot be excluded that the cr ews wer e intoxicated by another substance.” This incident highlights the value of installing and operating sensors onboar d, both to provide r eal-time information to the pilots and assist maintenance in subsequent tr oubleshooting. Other than its investigation into these ten turbopr op crashes in 1979–1981, the NTSB has not weighed in on the flight safety implications of pilots inhaling oil-contaminated bleed air inflight. This is contrary to its counterparts in Australia [ 32 , 33 ], Germany [ 4 ], Iceland [ 34 ], Ir eland [ 35 ], New Zealand [ 36 ], Spain [ 5 ], Sweden [ 37 ], Switzerland [ 7 ], and the UK [ 3 , 6 ], for example. Each of those safety boar ds has investigated one or more commer cial flights involving pilots whose inflight impairment compromised flight safety and has concluded that br eathing contaminated bleed air either likely or definitively played a r ole. The NTSB does r equire airlines to r eport onboard fume/smoke events, but only if either the air craft sustained structural damage or if specific health impacts wer e reported by one or mor e occupant (49 CFR § 830.2). However , oil fume events that meet the NTSB r eporting criteria have not been investigated. 4.2. Bearing and Seal Failur es in the TPE331 Engine The description in [ 16 ] of the two seals in series contains some contradictions. Accor d- ing to the explanation, the carbon seal is necessary because “when the engine is shutdown, oil drains from the engine walls which incr eases the oil level above the shaft installation level of the compr essor” [ 16 ] (p. 33). The labyrinth seal is necessary because the carbon seal is potentially “subject to wear and damage” [ 16 ] (p. 2). So, if the carbon seal is worn or damaged, then the oil will flow out of the r eduction gearbox into the compressor and con- taminate the cabin air when the engine is next started up. This situation was investigated in test 5 [ 16 ]. It is known that all seals leak in small quantities [ 38 ]. Pr essure dif ferentials assumed by the manufactur er may not be present in failur e cases. Moreover , pr essure dif ferentials may not be suf ficient during rapid thrust reduction or at idle thr ust. In test 4, it was assumed only that one of the two seals in series (the carbon seal) would have failed. The labyrinth seal was left intact. Certainly , a mechanical failur e that causes the carbon seal to fail may also cause the labyrinth seal to fail at the same time. For example, a failure of the main shaft compr essor bearing could cause the main shaft to vibrate or rotate eccentrically which could sever ely damage (or even destroy) both seals. In addition to crash number 1 (T able 5 ), an TPE331 compressor bearing failur e which caused the engine to fail was documented by the Australian T ransport Safety Bureau (A TSB) [ 39 ], although without either fatalities or refer ence to oil fumes. That r eport described the history of compr essor bearing failures on the TPE331 engine which peaked in the early to mid-1980s. Garr ett attributed the compr essor bearing failures to pr opeller strikes and subsequently r evised the engine maintenance manual, which—by the 1990s— r educed the number of failures. In the accident investigated by the A TSB, when the compr essor bearing failed, the bearing cage fractured which caused the balls to come loose. Such loose components can collide with and cause damage to numerous internal r otating engine components, including the compr essor seals. 4.3. Bleed Air T esting Regar ding the engine bleed air testing reported by the NTSB [ 16 ], the conditions in trials 1–4 did not r epresent the conditions of concern on the crashed air craft because the Aerospace 2021 , 8 , 389 14 of 20 engine compr essor carbon seal was intact and, in all but one case, the air was filtered for vapor and particulate. No measur ements wer e collected during trial 5a. Regar ding the r elevance of conditions tested during trial 5b, on the one hand, the bleed air would have contained oil fr om the dirty engine start, but it is not clear if this is the same volume and pattern of oil as with a faulty engine compr essor carbon seal inflight. Mor eover , the bleed air had been passed thr ough a glass wool filter for vapors and particulate, unlike on the crashed air craft. Finally , it is not clear if the temperatures in the test stand compr essor r eflected inflight conditions. It is important to car efully consider the question of the temperatur e in the engine compr essor on these crashed air craft. In its r eport, the NTSB r efer enced some certification data collected by a major engine manufactur er after injecting oil into a lar ge turbofan engine. The tests showed that that carbon monoxide formation was detectable starting around 316 ◦ C [ 16 ] (p. 7). The r eport also notes that TPE331 engine has a standar d compr essor dischar ge temperatur e of 360 ◦ C [ 16 ] (p. 6) with a maximum temperature of 386 ◦ C [ 16 ] (p. 25) . The compr essor temperatur e was high enough for carbon monoxide to be generated in the pr esence of oil, but the authors claim that the concentration of carbon monoxide would have been too low to cause impairment [ 16 ] (p. 2). The authors also rule out the pr esence of other oil decomposition pr oducts (such as acr olein) suf ficient to irritate the mucous membranes by noting that “a number of participants snif fed the bleed air lines . . . [and] no one described an acrid or irritating quality”; [rather] “the consensus was that the odor was that of a warm oil, not a decomposed oil” [ 16 ] (p. 27). In a companion study , CAMI r esear chers exposed test animals to Exxon 2380 oil for seven hours without, what the NTSB called, “any immediate or delayed behavioral change” [ 16 ] (p. 28). The CAMI r eport does describe an experiment with rats and chickens exposed to aer osolized (but unheated oil) in which the animals seemed unaf fected [ 17 ] (p. 14) . However , in the same study the CAMI r esear chers r eported that, when the engine oil was heated, carbon monoxide started to form at 306 ◦ C and when rats in one trial wer e exposed to oil fumes heated to 350 ◦ C for 30 min, “it was obvious that the animals were appr oaching incapacitation” [ 17 ] (p. 8). Mor eover , when the temperature was further incr eased, the animals “expir ed.” Unlike the rats, the pilots on the crashed planes would have inhaled oil fumes in a r educed pr essur e envir onment with a corr esponding r eduction in the partial pr essur e of oxygen in the ambient air . Mor e r ecent sampling data has highlighted the presence and potential health impact of elevated levels of ultrafine particles in the bleed air supplied to the cabin and flight deck on commer cial air craft [ 40 – 44 ]. As noted above, the authors of the NTSB r eport assumed that “particulate matter would not form” [ 16 ] (p. 9), and so did not assess any associated toxicity . 4.4. Regulations In the 1960s, a r eport fr om an air craft manufactur er (Douglas Air craft Corporation) describes the need to “show that the level of contamination requir ed for olfactory warning is well below the generally accepted tolerance limits for the toxic materials produced” [ 15 ] (p. 3). In 1960, U.S. aircraft manufactur ers would have been r equir ed to demonstrate to the U.S. Civil Aer onautics Boar d (which pr edated the F AA) that air craft systems wer e designed to pr ovide ventilation air “fr ee fr om harmful or hazar dous concentrations of gases or vapors”, which included (but was not limited to) the carbon monoxide concentration not exceeding 50 ppm [ 45 ]. Pr esumably , this is what motivated Douglas Air craft Corporation to pr opose testing to demonstrate that, “under all possible oil leakage rates,” olfactory warnings would give pilots suf ficient time to “permit effective cr ew countermeasur es.” [ 15 ] (p. 3). Essentially , tests needed to show that pilots would smell oil fumes before they would be impair ed, pr oving that the pr esence of oil-based contaminants in bleed air was safe. Since then, many studies and r eports discuss the pr esence of airborne contaminants in cabin air and comment on whether the levels are “safe” or “acceptable” [ 40 , 46 – 48 ]. “Acceptability” has mor e commonly been framed in the context of comparing air craft data Aerospace 2021 , 8 , 389 15 of 20 to published exposur e limits for individual chemical constituents [ 16 , 40 , 49 , 50 ], although this appr oach is not without criticism [ 51 , 52 ]. The quest to define “safe” or “acceptable” concentrations of oil-based compounds is likely borne fr om the need for industry to comply with the r egulation that the aircraft supply system be designed to supply air that is “fr ee fr om harmful or hazardous concen- trations of gases or vapors” (14 CFR § 25.831(b)). If something is acceptable—if it is not harmful—then the design meets the r egulation. Inter estingly , though, the F AA does not de- fine “harmful or hazar dous” beyond its limits for carbon monoxide (14 CFR § 25.831(b)(1)) and carbon dioxide (14 CFR § 25.831(b)(2)) and it had not done so in the early 1980s either . Applying published exposur e limits for individual chemicals to complex mixtur es [ 53 ] (Appendix 10) is pr oblematic [ 54 ], especially in a r educed pressur e and safety-sensitive en- vir onment [ 52 ]. This is in part because exposur e limits do not exist for every constituent in these mixtur es and the various constituents have a variety of toxicity endpoints. Mor eover , the diversity of exposur e limits published by dif fer ent authorities for a single chemical illustrates the fallacy that a single number can define the boundary between what is and is not acceptable. In the case of the F AA, their limits for carbon monoxide and carbon monox- ide ar e as high—or higher —than published chemical exposur e limits for gr ound-based application. So, given this gap in the r egulatory framework, in 1981, the NTSB and their industry colleagues defined “safety” for themselves—not in the context of certification r egulations, but in the context of whether pilots could have been impair ed. The authors of the 1984 NTSB report acknowledged that carbon monoxide would be generated when oil was purposefully introduced into the compr essor section of the TPE331 engine, but they noted that it should be “well below permissible limits in the bleed air” [ 16 ] (p. 2). However , the permissible exposur e limit for carbon monoxide is not a useful benchmark for safety . An applied r esear ch study into the effects of exposur e to carbon monoxide inflight concluded that “the maximum permissible concentration of carbon monoxide in pr essurized passenger airplane cabins should be 0.01 mg/liter ,” which is equivalent to 8.7 ppm [ 55 ]. By comparison, the permissible air craft design limit for carbon monoxide is 50 ppm (14 CFR § 25.831(b)(1)) which is, inexplicably , as high, or higher than gr ound-based limits. This, even though it is primarily applied in a r educed pr essur e envir onment (14 CFR § 25.841(a)) with a corr esponding reduction in the partial pr essur e of oxygen available to occupants. Safety of flight depends on pilots’ alertness and r eaction time which can be compr omised by exposur e to asphyxiants, such as carbon monoxide [ 56 ]. Mor eover , aircraft occupants have no means of egr ess once the doors ar e closed, such that an additional safety factor r egar ding exposur e to carbon monoxide is warranted. Finally , carbon monoxide is only one element of a complex chemical mixtur e. 4.5. Exposur e Contr ol Measur es Just as the flight safety implications of br eathing oil and hydraulic fluid fumes have been well documented, the need for control measur es has also long been r ecognized. In 1966, an air craft manufactur er reported that, in r esponse to the evidence that contaminated bleed air could have caused some fatal crashes, the Navy r equir ed that cr ewmembers br eathe 100% oxygen from takeof f to landing [ 15 ]. In 1955, an engineer with North Ameri- can A viation described the outcome of a two-year investigation into engineering solutions to pr event bleed air contamination, r ecommending either a separate compr essor or a bleed air filter [ 57 ]. In r esponse to one oil fume event during the descent phase of a commer cial flight, the UK Air Accidents Investigation Boar d r ecommended that the F AA and EASA “consider r equiring” a system to warn pilots about the presence of “smoke or oil mist in the air deliver ed fr om each air conditioning unit” [ 58 ]. Engineering and operational measur es continue to be called for , including bleed air filtration, sensors to provide early warning of airborne contaminants, impr oved maintenance pr ocedures, mor e tar geted tr oubleshooting pr ocedur es, r elocating the air inlet for the auxiliary power unit, and airline worker training and education [ 59 , 60 ]. Aerospace 2021 , 8 , 389 16 of 20 5. Conclusions Between 1979 and 1981, NTSB investigators suggested that inhaling oil fumes inflight may have been a causal factor in “several” fatal crashes of turboprop air craft. In r esponse, the agency partner ed with the very companies that had a commercial inter est in the outcome of the investigation. Aside fr om noting the potential for some people to develop “extr eme chemical sensitivity” [ 16 ] (p. 28) to chemicals in oil fumes, the NTSB and their industry partners soundly dismissed the hypothesis that oil fumes may have impair ed some of the pilots on the crashed planes, af firming that it was “completely without validity” [ 16 ] (p. 3). However , their conclusions ar e not supported by the evidence for three key r easons. First, it was not—and is not—possible to draw any definitive conclusions regar ding the cause of these crashes because r eal-time bleed air testing and suitable post-mortem blood analyses wer e not available. However , the accident reports for four of the fatal crashes on these turbopr op aircraft include details consistent with (and suggestive of) the pilots being impair ed by oil fumes (T able 5 ). Mor eover , this is consistent with similar concerns and r eports of pilot impairment documented since the 1930s, such that “pilot err or” and “undetermined” are insuf ficient explanations. W ithout air supply monitoring equipment to pr ovide real-time warning, and without options for a blood test to investigate inhalation of oil fumes, air craft crashes that are attributable to bleed air contaminants will not be r ecognized as such. Second, none of the tests of gr ound-based bleed air measurements of a subset of oil-based contaminants generated in the engine type that had been on the crashed air craft r eproduced the types of inflight conditions that the accident investigators had flagged as potentially unsafe (T ables 3 and 5 ). Specifically , the engine test stand conditions did not assess the impact of oil seeping thr ough a cracked or otherwise damaged compressor seal on the quality of unfilter ed bleed air downstream. As a r esult, the bleed air testing results ar e not relevant to the question of whether oil fumes could have impair ed the pilots inflight. As such, the ar gument that they somehow discount the potential for impairment is invalid. Finally , to interpret the bleed air data they collected, the authors of the r eport used pub- lished exposur e limits as a benchmark for whether the concentration of gaseous compounds in oil fumes would have been suf ficient to cause pilot impairment. However , published ex- posur e limits are not appr opriate for assessing the risks associated with inhaling a complex mixtur e of compounds in an enclosed and reduced pr essure envir onment. The significant concerns raised by these crashes and the history of pilot impairment associated with br eathing oil fumes all support more stringent design, operation, and r eporting regulations to pr otect safety of flight. 6. Recommendations • For curr ent aircraft that ar e equipped with bleed air systems, engineering control measur es such as sensors and filters should be mandated to prevent inflight exposur e to fumes and, thus, impr ove flight safety . For new aircraft types, non-bleed air supply systems should be standar d. • Given the flight safety implications, all cr ewmembers should be trained to recognize and r espond to the presence of bleed air contaminants [ 61 ]. • The NTSB should r eopen the 1984 report and update the conclusions based on what was known then about oil fumes and flight safety , and considering the data and reports published since then. The NTSB should also issue r ecommendations to the F AA on necessary actions to minimize the flight safety impacts of exposur e to oil fumes. • Un ti l su it ab ly p r ot ect iv e me as ur e s ar e i mp le men te d fl ee t- wi de , th e NT SB s ho ul d co nsi de r pi lo t im pa ir me nt f r om b lee d- so ur c ed f um es a s a po ten ti al c as ua l fa ct or i n fut ur e a ir c ra ft ac ci de nt i nv es ti gat io ns . T hi s is p ar ti cu la rl y imp or ta nt w he n an a cc ide nt i nc lu de s ei th er r el ev an t ma in te na nc e his to ry o r a pi lo t’ s fa ilu r e to c om mu ni ca te , for e xa mp le . • If only to avoid the appearance of bias, future investigations should be independent of all commer cial interests. Even though it is not unusual for the NTSB to include the F AA and manufacturers in accident investigations, both the poorly conceived design Aerospace 2021 , 8 , 389 17 of 20 of the air sampling trials and the sweeping conclusions, suggest that commer cial conflicts influenced this pr oject. Author Contributions: Conceptualization and methodology , J.A. and D.S.; investigation, J.A.; writing—original draft pr eparation, J.A.; writing—r eview and editing, J.A. and D.S. All authors have read and agr eed to the published version of the manuscript. Funding: This resear ch r eceived no external funding. Informed Consent Statement: Not applicable. Data A vailability Statement: No new data wer e created in this study . Data sharing is not applicable to this article. Conflicts of Interest: The authors declare no conflict of inter est. Abbreviations The following abbreviations ar e used in this manuscript. CAMI United States Civil Aeromedical Institute CFR United States Code of Federal Regulations CS Certification Specification (issued by EASA) EASA European Union A viation Safety Agency F AA United States Federal A viation Administration (issued by the F AA) F AR United States Federal A viation Regulation lb/hr pounds per hour NTSB United States National T ransportation Safety Board psia pound-force per squar e inch absolute (r elative to zer o or absolute vacuum) psig pound-force per squar e inch gauge (r elative to atmospheric pr essur e; at sea level 14.7psi) rpm r evolution per minute TPE turbopr op engine References 1. Scholz, D. Aircraft cabin air and engine oil—An engineering view . In Pr oceedings of the 2017 International Aircraft Cabin Air Conference, London, UK, 19–20 September 2017. [ Cr ossRef ] 2. Michaelis, S. Air craft clean air requir ements using bleed air systems. Engineering 2018 , 10 , 142–172. [ Cr ossRef ] 3. UK Air Accidents Investigation Branch (AAIB). Bulletin No. AAIB-26125, Airbus A320-232, G-EUYB ; UK Department for T ransport: Aldershot, UK, 2020, A vailable online: https://perma.cc/GWD2- R WVW (accessed on 30 September 2021). 4. Bundesstelle für Flugunfalluntersuchung (BFU). Study of Reported Occurrences in Conjunction with Cabin Air Quality in Commer cial T ransport Air craft. Report No. BFU 803.1-14 ; German Federal Bureau of A viation Accident Investigation: Braunschweig, Germany , 2014, A vailable online: https://perma.cc/XPR9- GE6E (accessed on 30 September 2021). 5. Civil A viation Accident and Incident Investigation Commission (CIAIAC). Interim Statement A-008/2013: Accident Occurred to Aircraft Boeing B-757-300, Registration D-ABOC, Operated by Condor Flugdienst GmbH, at Gran Canaria Airport on 22 March 2013 ; Civil A viation Accident and Incident Investigation Commission (CIAIAC): Madrid, Spain, 2014, A vailable online: https: //perma.cc/89DJ- Y42Q (accessed on 1 October 2021). 6. UK Air Accidents Investigation Branch (AAIB). Bulletin No. 3/2013, Boeing 757-28A, G-FCLA, EW/G2012/10/09 ; UK Department for T ransport: Aldershot, UK, 2013, A vailable online: https://perma.cc/QE5D- SLDX (accessed on 30 September 2021). 7. Swiss Aircraft Accident Investigation Bureau (SAAIB). Investigation Report Concerning the Serious Incident to Aircraft A VRO 146-RJ 100, HB-IXN Operated by Swiss International Air Lines Ltd. Under Flight Number LX1103 on 19 April 2005 on Approach to Zurich-Kloten Airport ; Swiss Air craft Accident Investigation Bur eau (SAAIB): Berne, Switzerland, 2006, A vailable online: https://perma.cc/3GK4- KPPE (accessed on 1 October 2021). 8. Federal A viation Administration (F AA). Airworthiness Directive 2004-12-05: BAE Systems (Operations) Limited Model BAe 146 Series Airplanes. Docket No. 2003-NR-94-AD ; Federal A viation Administration (F AA): W ashington, DC, USA, 2004. 9. Bobb, A.J.; Still, K.R. Known Harmful Effects of Constituents of Jet Oil Smoke ; Naval Health Research Center , T oxicology Detachment, W right-Patterson Air For ce Base: Dayton, OH, USA, 2003. [ Cr ossRef ] 10. Kelso, A.G.; Charlesworth, J.M.; McV ea, G.G. Contamination of Envir onmental Contr ol Systems in Hercules Air craft: MRL-R-1116, AR-005-230 ; Australian Government Department of Defence: Melbourne, Australia, 1988, A vailable online: https://perma.cc/ WS8C- B83F (accessed on 22 October 2021). 11. Rayman, R.B.; McNaughton, G.B. Smoke/fumes in the cockpit. A viat. Space Envir on. Med. 1983 , 54 , 738–740. [ PubMed ] Aerospace 2021 , 8 , 389 18 of 20 12. Montgomery , M.R.; W ier , G.T .; Zieve, F .J.; Anders, M.W . Hu man intoxication following inhalation exposure to synthetic jet lubricating oil. Clin. T oxicol. 1977 , 11 , 423–426. [ Cr ossRef ] 13. White, J.J. Carbon Monoxide and Its Relation to Aircraft. United States Naval Medical Bulletin ; United States Government Printing Office: W ashington, DC, USA, 1932, A vailable online: https://perma.cc/B4NW - DUL T (accessed on 1 October 2021). 14. Armstrong, H.G. Noxious fluids and gases in aviation: Hot oil fumes. In Principles and Practice of A viation Medicine ; W illiams and W ilkins Company: Baltimore, MD, USA, 1939; pp. 178–180. 15. Douglas Aircraft Corporation (DAC). Suitability of Engine High Pr essure Bleed Air for Envir onmental Control Usage—Assurance T ests ; Douglas Aircr aft Corporation (DAC): Santa Monica, CA, USA, 1966, A vailable online: https://perma.cc/6EP A- DM8X (accessed on 1 October 2021). 16. US National T ransportation Safety Board (NTSB). Special Investigation Report: An Evaluation of the Garrett TPE 331 Engine’ s Potential for T urbine Oil By-Product Contamination of an Air craft Cabin Environmental System. Report No. NTSB/SIR-84/01 ; US National T ransportation Safety Board (NTSB): W ashington, DC, USA, 1984, A vailable online: https://perma.cc/T46K- FRUS (accessed on 1 October 2021). 17. Crane, C.R.; Sanders, D.C.; Endecott, B.R.; Abbott, J.K. Inhalation T oxicology: III. Evaluation of Thermal Degradation Pr oducts from Aircraft and Automobi le Engine Oils, Aircraft Hydraulic Fluid, and Mineral Oil ; Report No. F AA-AM-83-12; US Federal A viation Administration (F AA) Of fice of A viation Medicine: W ashington, DC, USA, 1983, A vailable online: https://perma.cc/V6CN- GCDU (accessed on 1 October 2021). 18. US Federal A viation Administration (F AA). Airplanes Flying Handbook, F AA-H-8083-3C ; US Federal A viation Administration Flight Standards Service: W ashington, DC, USA, 2021, A vailable online: https://n2t.net/ark:/13960/t3720ss1s (accessed on 28 October 2021). 19. Kugellager Express GmbH. Ball-Bearing 6204, Open. Picture. 2021. A vailable online: https://perma.cc/E6C6- 93GJ (accessed on 4 November 2021). 20. The Archive. British Aerospace Memorabilia, Garr ett TPE331 T urbopr op. 2020. A vailable online: https://perma.cc/3CXE- NQQ9 (accessed on 3 November 2021). 21. Hecker , S. IV .B.1. Engine oil and hydraulic fluid sample analysis. In Cabin Air Quality Incidents Project Report ; Occupational Health Research Consortium in A viation (OHRCA): Eugene, OR, USA, 2014, A vailable online: https://perma.cc/WD9K- 499J (accessed on 22 October 2021). 22. Anderson, J. Sour ces of onboard fumes and smoke r eported by U.S. airlines. Aerospace 2021 , 8 , 122. [ CrossRef ] 23. Horne, T .A. T urbine Pilot Used T urbine Review: Mitsubishi MU-2s ; Aircraft Owners and Pilots Association (AOP A): Frederick, MD, USA, 1994, A vailable online: https://perma.cc/P5FK- RQHF (accessed on 22 October 2021). 24. Bureau of Air Safety Investigation (BASI). MU-2 Accident Investigation and Resear ch Report ; Bureau of Air Safety Investigation (BASI): Canberra, Australia, 1992, A vailable online: https://perma.cc/3FLS- LL82 (accessed on 22 October 2021). 25. Lebeda, A. Mitsubishi MU-2B. Photograph. 2005. A vailable online: https://commons.wikimedia.org/wiki/File:Mitsubishi_MU- 2B_AN1706942.jpg (accessed on 21 October 2021). 26. McDougall, G.; Cho, D.W . Estimating practical maximum flight hours for general aviation turbopr op and jet aircraft. T ransp. Res. Rec. 1989 , 1214 , 52–55. A vailable online: https://perma.cc/SHX7- 5YQ4 (accessed on 22 October 2021). 27. Michaelis, S. Air Accident Bureau incident reports—Case study r eview . In Proceedings of the 2021 International Air craft Cabin Air Conference, Online, 15–18 Mar ch 2021. [ CrossRef ] 28. UK Air Accidents Investigation Branch (AAIB). Bulletin No. 6/2009, Boeing 757-204, G-BY AO, EW/C2006/10/08 ; UK Air Accidents In- vestigation Branch (AAIB): Aldershot, UK, 2009, A vailable online: https://perma.cc/TQX5- T ASE (accessed on 29 October 2021 ). 29. UK Air Accidents Investigation Branch (AAIB). Bulletin No. 5/2013, Airbus A321-131, D-AIRX, EW/G2012/10/12 ; UK Air Accidents Investigation Branch (AAIB): Aldershot, UK, 2009, A vailable online: https://perma.cc/JRK4- CKSZ (accessed on 29 October 2021 ). 30. Blumenfeld, L. A clean APU means clean cabin air . Flight Airworth. Support T echnol. (F AST) 2013 , 52 , 4–9, Airbus SAS. A vailable online: https://perma.cc/ZK7P- JZ8V (accessed on 29 October 2021). 31. French Bur eau of Enquiry and Analysis for Civil A viation Safety (BEA). Serious Incident to the Airbus A320-214 Registe red EC-HQJ on 17 November 2017 en Route between Geneva and Bar celona. Report No. BEA2017-0658; French Bur eau of Enquiry and Analysis for Civil A viation Safety (BEA): Paris, France, 2020, A vailable online: https://perma.cc/2FMQ- VGVW (accessed on 2 November 2021). 32. Australian T ransport Safety Bur eau (A TSB). An Analysis of Fumes and Smoke Events in Australian A viation, 2008–2012 ; A viation Research Report AR-2013-213; Australian T ransport Safety Bureau (A TSB): Canberra, Australia, 2014, A vailable online: https: //perma.cc/7P3W - WDDU (accessed on 5 October 2021). 33. Parliament of the Commonwealth of Australia (PCA). Air Safety and Cabin Air Quality in the BAE 146 Aircraft ; Senate Rural and Regional Af fairs and T ransport References Committee of the Parliament of the Commonwealth of Australia: Canberra, Australia, 2000, A vailable online: https://perma.cc/QPB3- RUL3 (accessed on 6 October 2021); ISBN 0-642-71093-7. 34. Ranns ó knarnefnd Flugslysa (RNF). Final Report: Aircraft Serious Incident—Smoke in Flight Deck and Cabin, Engine Shut Down and an Emergency Landing ; Report No. M-01409/AIG-09; Ranns ó knarnefnd Flugslysa (RNF): Reykjavik, Iceland, 2009, A vailable online: https://perma.cc/6DDS- R9T A (accessed on 6 October 2021). Aerospace 2021 , 8 , 389 19 of 20 35. Air Accident Investigation Unit (AAIU). Serious Incident: Boeing 737-8AS, EI-EFB near Stansted, United Kingdom ; Report No. 2016-013; Ireland Department of T ransport, T ourism, and Sport Air Accident Investigation Unit: Dublin, Ireland, 2016, A vailable online: https://perma.cc/DKR2- AZNX (accessed on 25 October 2021). 36. New Zealand T ransport Accident Investigation Commission (T AIC). Dornier 228-202 ZK-VIR. Partial Incapacitation of Flight Crew en Route W estport to Christchurch, 30 Mar ch 2007 ; Report No. 07-002; New Zealand T ransport Accident Investigation Commission (T AIC): Auckland, New Zealand, 2008, A vailable online: https://perma.cc/9A4F- RMT A (accessed on 8 October 2021). 37. Statens Haverikommission (SHK). Accident Investigation into Incident Onboard Aircraft SE-DRE during Flight between Stockholm and Malmo M County , Sweden ; Report No. RJ 2001:41e; Statens Haverikommission (SHK): Stockholm, Sweden, 2001, A vailable online: https://perma.cc/K2R T - FXKZ (accessed on 1 October 2021). 38. Scholz, D. Air craft cabin air and engine oil—An engineering view . J. Health Pollut. 2019 , 9 , 93–98. [ CrossRef ] 39. Australian T ransport Safety Bureau (A TSB). In-Flight Engine Failure 23 km N of Ardr ossan, SA 25 July 2007 VH-OAA Cessna Aircraft Company “Conquest II” 441. A viation Occurrence Investigation—AO-2007-030 ; Australian T ransport Safety Bureau (A TSB): Canberra, Australia, 2009, A vailable online: https://perma.cc/A3WS- 3R7Q (accessed on 2 November 2021). 40. Crump, D.; Harrison, P .; W alton, C. Air craft Cabin Air Sampling Study: Part 1 of the Final Report ; Institute of Environment and Health: Cranfield, UK, 2011, A vailable online: https://perma.cc/G3F A- Q8LL (accessed on 22 October 2021). 41. Michaelis, S.; Loraine, T .; Howard, C.V . Ultrafine particle levels measured on boar d short-haul commercial passenger jet air craft. Environ. Health 2021 , 20 , 1–14. [ Cr ossRef ] [ PubMed ] 42. W illiams, P .I.; T rembath, J. Simultaneous inboard and outboar d, inflight measur ements of ultrafine particle concentrations. Aerosol Sci. T echnol. 2021 , 55 , 614–622. [ CrossRef ] 43. Howard, C.V .; Johnson, D.W .; Morton, J.; Michaelis, S.; Supplee, D.; Burdon, J. Is a cumulative exposur e to a background aer osol of nanoparticles part of the causal mechanism of aerotoxic syndr ome? J. Nanomed. Nanosci. Res. 2018 , 139 , A vailable online: https://perma.cc/2CU6- L7HN (accessed on 15 October 2021). 44. Jones, B.W .; Amiri, S.N.; Roth, J.W .; Hosni, M.H. The nature of particulates in air craft bleed air resulting fr om oil contamination. Paper no. L V -17-C046. In Pr oceedings of the 2017 ASHRAE W inter Conference, Las V egas, NV , USA, 28 January–1 February 2017; American Society of Heating Refrigerating and Air Conditioning Engineers: Atlanta, GA, USA. A vailable online: https: //perma.cc/UAS8- BTLH (accessed on 22 October 2021). 45. Civil Aeronautics Boar d (CAB). Section 4b.371(b): V entilation, Heating, and Pressurization. Civil Air Regulations Part 4b: Airplane Airworthiness T ransport Categories ; Civil Aeronautics Board (CAB): W ashington, DC, USA, 1953, A vailable online: https://perma. cc/JS2Y - TMPH (accessed on 22 October 2021). 46. Federal A viation Administration Office (F AA). Aircraft Cabin Bleed Air Contaminants: A Review . Report No. DOT/F AA/AM- 15/20 ; Federal A viation Administration Office of Aer ospace Medicine: W ashington, DC, USA, 2015, A vailable online: https: //perma.cc/ZF7Z- P45P (accessed on 5 October 2021). 47. Spengler , J.D.; V allarino, J.; McNeely , E.; Estephan, H. In-Flight/Onboard Monitoring: ACER’ s Component for ASHRAE 1262, Part 2 ; Report No. RITE-ACER-CoE-2012-6; National Air T ransportation Center of Excellence for Research in the Intermodal T ransport Environment (RITE), Airliner Cabin Envir onment Research (ACER) Pr ogram: Boston, MA, USA, 2012, A vailable online: https://perma.cc/D68W - XW56 (accessed on 6 October 2021). 48. UK Civil A viation Authority (CAA). Cabin Air Quality: Report 2004/04 ; UK Civil A viation Authority (CAA): W est Sussex, UK, 2004, A vailable online: https://perma.cc/MP4H- 3AUG (accessed on 22 October 2021). 49. Chen, R.; Fang, L.; Liu, J.; Herbig, B.; Norrefeldt, V .; Mayer , F .; Fox, R.; W argocki, P . Cabin air quality on non-smoking commercial flights: A review of published data on airborne pollutants. Indoor Air 2021 , 31 , 926–957. [ Cr ossRef ] [ PubMed ] 50. W aters, M.A.; Bloom, T .F .; Grajewski, B.; Deddens, J. Measurements of indoor air quality on commer cial transport aircraft. In Proceedings of the 9th International Confer ence on Indoor Air Quality and Climate, Santa Cruz, CA, USA, 30 June–5 July 2002; pp. 782–787. A vailable online: https://perma.cc/M86Y - QMP2 (accessed on 8 October 2021). 51. Howard, C.V . Inappropriate use of risk assessment in addr essing health hazards posed by civil air craft cabin air . Open Access J. T oxicol. 2020 , 4 , 049–056. [ Cr ossRef ] 52. W atterson, A.; Michaelis, S. Use of exposure standar ds in aviation. 2017 Int. Aircr . Cabin Air Conf. 2019 , 9 , S132–S137. [ CrossRef ] 53. Michaelis, S. A viation Contaminated Air Reference Manual ; Printed and bound by CPI Antony Rowe: Eastbourne, UK, 2007; ISBN 978-0-9555672-0-9. 54. American Conference of Governmental Industrial Hygienists (ACGIH). Appendix E: Threshold limit values for mixtur es. In TL Vs and BEIs Based on the Documentation of Threshold Limit V alues for Chemical Substances and Physical Agents and Biological Exposure Indices ; American Conference of Governmental Industrial Hygienists: Cincinnati, OH, USA, 2021. 55. Gilinskiy , V .A.; Chapek, A.V .; Kozlova, A.G.; Kulikova, N.M.; Loshak, A.Y . The effects of low concentrations of carbon monoxide on man in pressurized cabins of passenger planes. In A viation and Space Medicine, NASA T echnical T ranslation F-228 ; Parin, V .V ., Ed.; US National Aeronautics and Space Administration: W ashington, DC, USA, 1964, A vailable online: https://perma.cc/XAB2- KETY (accessed on 1 October 2021). 56. United States Air Force (USAF). Envir onmental Control Airborne. Appendix B: Air For ce Guide Specification MIL-E-87145A ; United States Air Force W right Patterson Air Force Base: Dayton, OH, USA, 1992, A vailable online: https://perma.cc/N8UV - CT A V (accessed on 1 October 2021). Aerospace 2021 , 8 , 389 20 of 20 57. Reddall, H.A. Elimination of engine bleed air contamination. In Pr oceedings of the SAE Golden Anniversary Aer onautic Meeting, Los Angeles, CA, USA, 11–15 October 1955, A vailable online: https://perma.cc/9WMT - CESM (accessed on 1 October 2021). 58. UK Air Accidents Investigation Branch (AAIB). Bulletin 4/2007, Bombardier DHC-8-400, G-JECE, EQ/C2005/08/10 ; UK Air Accidents Investigation Branch (AAIB): Aldershot, UK, 2007, A vailable online: https://perma.cc/L2GG- ZSLX (accessed on 6 October 2021). 59. American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE). Guideline 28-2021: Air Quality within Commercial Air craft. American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE): Atlanta, GA, USA, 2021. A vailable online: https://www .techstr eet.com/ashrae/sear ches/33473309 (accessed on 28 October 2021). 60. American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE). ANSI/ASHRAE Standard 161-2018: Air Quality within Commercial Air craft. American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE): At- lanta, GA, USA, 2018. A vailable online: https://www .techstr eet.com/ashrae/sear ches/33473313 (accessed on 28 October 2021 ). 61. International Civil A viation Organization (ICAO). Guidelines on Education, T raining, and Reporting Practices Related to Fume Events. Cir cular 344-AN/202 ; International Civil A viation Organization (ICAO): Montr eal, QC, Canada, 2015, A vailable online: https://www .icao.int (accessed on 1 November 2021). Oil Fumes , Fligh t Saf e ty , and the NTSB Judith Ander son, MSc CIH Industrial Hy gienis t Air Saf e ty , Health and Security Department Associa tion of Fligh t A t tendan ts-CW A, AFL- CIO Aircraft Cabin Air Conference March 16, 2021 Ov er vie w 1. Who sa y s oil fumes c an c ompr omise fligh t saf e ty? 2. NS TB in v es tig a tion in t o 10 cr ashes (i ncluding highli ghts of acciden t r eports - 1978, 1979) 3. Mor e r ece n t e x amples of c ompr omised fligh t saf e ty 4. R ecommenda tions Compr omised fligh t sa f e ty e x ample- 1939 A v . medicine t e xtbook, writ t en by ph y sician in US Arm y , Aer omedic al R esear ch Lab Arms trong, H G (1939) “No xious fluids and g ases in a viati on: hot oil fumes” (pp. 178 -180), In: Pri nciples and Pr actice of A viation Medici ne , Aer o Medic al R esearc h Labor atory , Unit ed Sta tes Arm y , P ub l ished by The Will iams & Wilki ns Compa n y , Baltimor e, USA Compr omised fligh t sa f e ty e x ample- 1977 P eer-r e vie w ed paper autho r ed b y pulmonar y/t o xic ology specialis ts Montg omery , MR; Wier , GT ; Zie ve, F J; et al (1977) "Human in to xic ati on f ol lo wing inhala tion e xposur e t o s ynthetic jet lubri c ati ng oil ," Clin. T o xicol ., 11(4): 423- 426 Compr omised fligh t sa f e ty e x ample- 2004 US F eder al A via tion Adminis tr a tion Air w orthiness Dir ectiv e 2004- 12 - 05 (BaE146 air cr a ft) F AA (2004) “ Airwort hiness Dir ective 2004 - 12 -05: BAE S ys tems (Oper ati ons ) Limit ed Model BAe 146 Seri es Airplanes” Dock e t No. 2003 - NR- 94 -AD , F eder al A viati on Adminis tr ation, W ashing ton, DC Compr omised flight sa f e ty e x ample- 2015 In t erna tional Civil A via tion Or g aniz a tion ICA O (2015) “Guideli nes on educati on, tr aining , and report ing pr actices r elat ed to fume ev ents, ” Cir cular 344 -AN/202, Int ernational Civil A viation Or g aniz ati on, Montr eal, Canada Mor e e x amples of r eports tha t cit e c ompr omised fli ght sa f e ty: 1955 - 2020 • AAIB (2020 ) Bulletin no. 9/2020, Airbus A320-232, G-EUYB, UK A ir Acciden ts Investigation Branch, UK Department for Transp ort, Alders hot, E ngland. • IFALPA (2018) “Cabin fumes,” Human Performance Brie fing L eaflet 18HUPBL03 and Position Paper 18POS24, International Fede ration of Ai rline P ilo ts’ Associations, Montreal, Canada. • ASRS (2017) “Aviation Safety Reporting System inciden t ACN: 1437845” Aviation Safety Rep orting System, National Aeronautics and Sp ace Adm inis tration, Moffett Field , California • AAIU (2016) “Report no. 2016 -013: Se rious incident Boeing 737-8AS, EI- EFB near Stansted, United Kingdom, 18 Sept. 2014.” Air Accident Invest igation Unit o f Ire land, Dublin , Ireland • CIAIAC (2014) “Interim Statement A - 008/2013: Accident occ urred to aircraft Boeing B - 757 -300, registr ation D-ABOC, operate d by Co ndor F lugdiens t GmbH, at Gran Canaria airport on 22 March 2013,” Civi l Aviation Accident and Inciden t Investig ation Commission, Madrid , Spain • AAIB (2013) Bulletin no. 3/2013, Boeing 757-28A, G -FCLA (EW/G2012/10/09) , UK Air Accidents Investig ation Branch, UK Department fo r Transport, A lders hot, E nglan d • BFU (2012) “Bulle tin: Accidents and incid ents durin g operation of civilian aircraft, Novembe r 2011” German Fede ral Bureau of Aviation Ac cident Investi gation, Braunsch weig, Germany • AAIB (2009) Bulletin no. 6/09, Bo ein g 757, G-BYAO (EW/C2006/10/8), UK Air Accidents Investigati on Branch, UK De partment for Trans port, Aldershot, England • RNF ( 2009) “Final report: Aircraft se rious inciden t – Smoke in flight deck and cabin, engine shut- down and emergency landing” Icelandic Air craft Accide nt Investigation Board (Rannsóknarne fnd flugslysa), Reykjavik, Iceland • CAA (2008) “Flight Operations Department Co mmunications (FODCOM) 17/2008” UK Civi l Aviation Authority, Safety Reg ulation Group, Aviation Ho use, Gatwick, West Susse x, England • AAIB (2007) Bulletin no. 4/2/07, Bo mbardi er DHC -8-400, G-JECE (E W/C2005/08/10), UK Air Accidents Investigati on Branch, UK Department fo r Tra nsport, A lders hot, England • ATSB ( 2007) “Pilot incapacitation: analysi s of medical conditions affecting p ilots involved in incide nts and accidents 1 Janu ary 1975 to 31 March 2006” Austr alian T ransport S afety Bureau, Aviation Research & A nalysis R eport – B2006/0170 • SAAIB ( 2006) “Investigati on report concerning the serious incide nt to aircraft AVRO 146 -R J 100, HB-IXN operated by Swiss International Air Li nes Ltd. Under flight number L X1103 on 19 April 2005 on app roach to Zu rich- Kloten airport” Swiss Aircraft Accide nt Investigation Bureau, Berne, Switzerland • AAIB (2004) Report no. 1/2004, BAe146, G-JEAK (EW/C2000/11/4) UK Air Accidents Investig ation Branch, UK Dep artment fo r Transport, Alders hot , England • CAA (2004) “Cabin air quality” CAA Paper 2004/04, Res earch Manage ment Depart ment, Safety Reg ulation Group, UK Civil Aviation Authority, Av iation House, Gatwick A irport South, West Susse x, England • NRC (2002) "The Airline r Cabin Environmen t and The Health of Passen gers and Crew," (excerp t) US National Research Council , ISBN 0- 309 - 08289 -7, National A cademy Press, Washington , DC • CAA (2002) “Flight Operations Department Co mmunications (FODCOM) 21/2002” UK Civi l Aviation Authority, Safety Reg ulation Group, Aviation Ho use, Gatwick, West Susse x, England • SHK (2001) "Report RL 2001:4 1e "Accident inves tigation into incident onboard aircraft SE -DRE duri ng fligh t between Stockholm and Malmo M Co unty, Swede n," Statens Haverikommission Bo ard of Acciden t Investig ation, Stockholm, Sweden • CAA (2001) "Flight Operations Departme nt Communication (FODCOM) 14/2001" UK Civil Aviation Authority, Safety Regulation Group, Aviation House, Gatwick, W est S ussex , England • CAA (2000) "Flight Operations Departme nt Communication (FODCOM) 17/2000" UK Civil Aviation Authority, Safety Regulation Group, Aviation House, Gatwick, W est S ussex , England • PCA ( 2000) “Technical report on air safet y and cabin air quality in the BAe146 aircraft," (ex cerpt) Parliament of the Commonwealth of Au stralia, Senate Rural and Regional Affairs and Transport Legislation Committee, Senate Printin g Unit, Canberra, A ustralia • ATSB ( 1999) “British Aerospace Plc BAe 146 -300, VH- NJF. Occurre nce brie f no. 199702276,” Au stralian Transport Safet y Bureau, Canberra, Austr alia •Lipscomb, J; Wals h, M; Caldwell , D; et al (1995) “Inhalation toxicity o f vapor p hase lub ricants” AL/OE - TR - 1997 -0090, US Air Force Armstrong Laboratory, Occ upati onal and Environmen tal Health Dire ctorate, Toxicology Division, Wright-Patterson Air Force Base, Oh io • Kelso, A G; Charle sworth, JM; and McVea, GG ( 1988) "Co ntamin ation of environmental control syste ms in Hercules aircraft: MRL -R -1116, AR- 005 -230," Aus tralian Government Departmen t of Defence , Defen ce Science and Technology O rganis ation, Melbourne, Australi a • Rayman, RB and McN aughton, GB (1983) "Smoke/fumes in the cockpit" Aviat. Space Environ. Med., 54(8) : 738- 740 • Paciorek, KL; Nakahara, JH; Kratzer , RH (1978) “Fl uid contamination of aircraft c abin air and breath ing oxygen” SAM - TR - 79 -34, Rep ort by Ultrasyste ms Inc. for USAF School o f A erospace Medicin e, Aerospace Me dical Division, Brooks Air Force Base , Texas • Crane, CR; Sande rs, DC; Endecott, BR; et al (1983) "In halation toxicology: III. Evaluation of th ermal degradation of products fr om aircraft an d automobile engine oils, aircraft h ydraulic fluid, and mine ral oil," Aviation Medicin e Report FAA AM- 83 -12, Civil Aeromed ical Institu te, US Federal Aviation Administrati on, Oklahoma City, Oklahoma • Treon, JF; Cappel , JW; Cleveland , FP; et al. (1955) “The toxicity of the products formed by the thermal decomposition o f ce rtain organic su bst anc es.” Am Ind Hyg Ass oc Quarte rly, 16(3): 187 - 195 Ov er vie w 1. Who sa y s oil fumes can compr omise fli gh t saf e ty? 2. NS TB in ves tig a tion in to 10 cr ashes (including highli ghts of acciden t r eports - 1979, 1980) 3. Mor e r ecen t e x amples of c ompr omised fligh t saf e ty 4. R ecommen da tions US Na tional T r ansport a tion Saf e ty Boar d (NT SB) • The NTSB is a US g ov ernmen t ag ency ov er seeing saf ety in tr ansport ation f or all modes (airlines, r ail w a ys, truck ing , et c.). • It is r esponsible f or in v es tig ating tr ansport ation acciden ts, c onducting tr ansport a tion saf ety s tudies, issuing sa f ety r ec ommendations, aiding victims’ f ami lies a ft er disas t er s, and pr omo ting tr ansport ation saf ety . • It w as es t ablished as an independen t agency bec ause it ma y ha ve t o in v es tig at e the r ole tha t gov ernmen t ag ency (e. g., F AA) pla y ed in an acciden t, f or e x ample. So , being independen t giv es NT SB mor e fr eedom t o be hones t and criticiz e the F AA (and other s), as needed, in the in t er es t of saf ety . NT SB r eporting /in v es tig a tion rules r ele v ant t o fume ev ents • In 1981, NT SB initia t ed an in v es tig a tion in t o 10 turbopr op c r ashes (197 9-81) in r esponse t o a h ypothesis tha t the pil ots had been impair ed by oil fum es – all air cr aft had the same engine lubric at ed with the same t ype of oil. The mos t import an t w or ds: “ se v er al a cciden t in v es tig a tions” “ adv er sely a f f ect fligh t cr e w ” “ c ould e xt end to all turbine engines” Ex ample: Fligh t fr om Salina, K S – Den v er , C O on Aug . 3, 1979 (N208 MA) • Thomas Mur fin: 34 y .o. pilot with 2,200 hour s of fligh t time; dry wea ther Air cr a ft cr ashed in Ha y s, K S • F ew minut es la t er , oil pr essur e w as a t z er o; pilot shut down R engine and r eport ed fumes and smok e onboar d (clear ed with r am air). • Pilot s t opped c ommunic ati ng with A T C. • Plane cr ashed in t o a field near the airport in Ha ys, K S. Mx in v es tig a tion & pos t -mort em • The c ompr essor bearing in engine had f ailed . • P os t- mort em f ound c arbon mono xide in blood. P ot en tial sour ces include oil fumes, engine fir e, e xplosion upon cr ash landing... Ex ample 2: Fligh t fr om Chic ago – New Orleans on F eb . 23, 1980 (N962MA) • M. James: 61 y .o. pilot with 10,000 hour s of fli ght time; dry w eather; c arrying six passeng er s • On appr oach, pilot s t opped r espondi ng t o A T C. Main t enance in v es tig a tion • Air cr aft had his t or y of air supp ly s y s tem-sour ced smok e/fumes. • Carbon seal in L engin e c ompr essor had r ecen tly been r eplaced “t o corr ect the discr epancy of smok e/fumes…” in the m x his t or y . E vidence of oil in bleed air • “Ex t ensiv e i n v es tig a tion f ailed t o r ev ea l that an air cr aft with such a c ondition would pr oduce adver se ef f ects on per sons inside this air cr aft. ” • “Oil y r esidue” in E CS downs tr eam of le ft eng ine Pr obable c auses of the 10 cr ashes: “unde t ermined” , “unknown” , “miscellaneous” , e t c. NT SB in v es tig a tion – the plan • During “ se v er al acciden t in v es tig a tions” a h ypothesis w as pr esen t ed t o the NTSB… • St ep 1: N TSB se t up a “Special In ves tig ativ e Commit t ee ” – memb er s included F AA , EP A , Garr et t (manuf act ur er of engi ne on all of the cr ashed pl anes) and Exx on (manuf actur er of oil lubri c a ting e ngine s on all of the cr ashed plane s) t o “ aid the sa f e ty boar d in in v es tig ating the h ypothesis ” . (Not unusual, but the optics ar e bad…) • The y made a plan to t es t oil -based c on t aminan ts in blee d air suppl ie d by the Garr e t t TPE 331 engine . NT SB in v es tig a tion: the measur ements • In July 1981, the y r an 12 trials (10-15 minut es each) and measured v arious c ont aminan ts in the bleed air supplied b y one o f tw o Garre t t TPE 331 eng ines lubric a t ed with Exx on 2380 oil ( T able IV). One of the engines had an in t act c arbon seal on the main shaft, one ha d a missing c arbon seal (w or s t-c ase f ailur e). • In 11 of the 12 trials, the y measur ed bleed air supplied by the engin e with in t act seal. Further , the bleed air w as passed thr ough a glass fiber filt er be f or e the sampling port (t o pre ven t c o n t amina tion of downs tream sampling equipmen t… so measur ed g ases). Added oil t o bleed air in 6 of the 11 trials, all of which wer e f ilt ered . T es ts didn’t r e flect c onditions of c oncern on the cr ashed air cr aft. • In one of the 12 trials , they measur ed bleed air supplied b y engine with missing seal AND no filt er AND oil c ont amina tion . But the oil was only hea t ed to 160°F f o r 15 minut es. Actual c ompr ess or t emp. would ha ve been 300- 600 ° F . T es t c onditions didn’t r e flect air cr aft c onditions. NT SB in v es tig a tion: the c onclusions 1. “…the quali ty of the bl eed air fr om the TPE - 331 engine is not measur ably dif f er en t fr om the quality of ambie n t air ” (ev en without a fr on t mainshaft compr essor carbon seal) 2. “No t o xic c ompounds of signific an t amoun ts w er e f ound in the ble ed air dur ing an y of the engine t es ts. ” 3. “ No evid ence tha t t o xic oil con t amina tion c ould occur…” Out c ome of acciden t in v es tig a tions • In the r eport ab s tr act, the NT SB t ook its c onclusi ons one s t ep further . Righ t aft er acknowledging the “t echnic al e xpertise” of Garr et t, Exx on, and the F AA f or f ormu la ting the t es ts and in t erpr eti ng the r esults , the y said tha t not only did oil fumes not inc apacit at e the pilots of those 10 air cr a ft -- c on t amina tion of t he c ompr essor air “ is not possible ”. Ex cep t tha t it is possible… • AAIB (2020 ) Bul letin no. 9/2020, A irbus A320-232, G -EUYB, UK Air Accidents Investig ation Branch, UK De partmen t for Transport, Alde rshot, E ngland. • IFALPA (2018) “Cabin fumes,” Human Performance Briefing Leaflet 18HUPBL03 and Position Paper 18POS24, Intern ational Federati on of Airli ne P ilo ts’ Associations, Montreal, Canada. • ASRS (2017) “Aviati on S afety Reportin g S ystem inciden t ACN: 1437845” Aviation Safety Reporting System, National Aeronautics and S pace Adm inistration, Moffett Field, California • AAIU (2016) “Rep ort no. 2016 -013: Seri ous inciden t Bo eing 737-8AS, EI- EFB near Stans ted, United Kingdom, 18 S ept. 2014.” Air Accide nt Invest igation Unit of Ireland , Dublin, Ireland • CIAIAC (2014) “ Interim Stateme nt A - 008/2013: Accident occurred to air craft Bo eing B - 757 -300, registrati on D-ABOC, operated by Condor Flug dienst GmbH, at G ran Canari a airport on 22 March 2013,” Civil Aviation Accident and Inciden t Investigati on Commission, Madrid, Spain • AAIB (2013) Bulletin no. 3/2013, Bo eing 757-28A, G-FCLA (EW/G2012/10/09), UK A ir Accidents Investigati on Branch, UK Department fo r Transp o rt , Ald ershot, England • BFU (2012) “Bulletin : Accidents and incid ents durin g operation of civilian aircraft, November 2011” German Federal Bureau of Aviation Ac cident Investigation, Braunschweig, Germany • AAIB (2009) Bulletin no. 6/09, Boeing 757, G-BYAO (EW/C2006/10/8), UK Air Accidents Investigati o n Branch, UK De partment for Trans port, Alde r shot, England • RNF ( 2009) “Final report: Ai rcraft serious incident – Smoke in flight deck and cabin, engine shut- down and emerg ency landing” Icelandic Air craft Acciden t Investigation Board (Rannsóknarne fnd flugslysa), R eykjavik, Iceland • CAA (2008) “Flig ht Operations Department Communications (FODCOM) 17/2008” UK Civil Aviation Authority, Safety Regu lation Group, Aviati o n Ho use, Gatwick, West Sussex , England • AAIB (2007) Bulletin no. 4/2/07, Bombardie r DHC -8-400, G-JECE (EW/C2005/08/10), UK A ir Accidents Investigati on Branch, UK Department fo r Transport, Ald ershot, England • ATSB ( 2007) “Pilot incapacitation: analys is of medical conditions affecting pilots involved in incidents and accidents 1 January 1975 to 31 March 2006” Australian T ransport S afety Bureau, Aviation Research & Analysi s Report – B2006/0170 • SAAIB ( 2006) “ Investigation report concerning the serious incident to aircraft AVRO 146 -R J 100, HB-IXN operated by Swiss Intern ational Air Lines Ltd. Under flight number LX1103 o n 19 April 2005 on app ro ach to Zurich- Kloten airport” Swiss Aircraft A c cident Investi gation Bureau, Berne, Switze rland • AAIB (2004) Report no. 1/2004, BAe146, G-JEAK (EW/C2000/11/4) UK Air Accidents Investig ation Branch, UK Department for Transport, A ldershot , England • CAA (2004) “Cabin air quali ty” CAA Pa per 2004/04, Research Man agement Department, Safety Regulation Group, UK Civi l Aviation Authority, Av iation Ho use, Gatwick Airport South, West Suss ex, England • NRC (2002) "The Airliner Cabin Environmen t and The Health of Passeng ers and Crew," ( excerp t) US National Research Coun c il, ISBN 0 - 309 - 08289 -7, National Acade my Press, Washington , DC • CAA (2002) “Flig ht Operations Department Communications (FODCOM) 21/2002” UK Civil Aviation Authority, Safety Regu lation Group, Aviati o n Ho use, Gatwick, West Sussex , England • SHK (2001) "Report RL 2001:41e "Accident investi gation into incide nt onboard aircraft SE -DRE du ring flight between Stockholm and Malmo M Co unty, Sweden ," Statens Haverikommission Bo ard of Accident Investigati on, Stockholm, Sweden • CAA (2001) "Fligh t O perations Department Co mmunication (FODCOM) 14/2001" UK Civil Aviation Authority, Safety Regulation Group, Aviation Ho use, Gatwick, West Sus sex, England • CAA (2000) "Fligh t O perations Department Co mmunication (FODCOM) 17/2000" UK Civil Aviation Authority, Safety Regulation Group, Aviation Ho use, Gatwick, West Sus sex, England • PCA ( 2000) “Technical report on air safety and cabi n air quali ty in the BAe146 air craft," ( excerp t) Parliament of the Commo nwealth of Au stralia, Senate Rural and Regional Affairs and Transport L egislati on Co mmittee, Senate Printing Unit, Canberra, A ustrali a • ATSB ( 1999) “British Aerosp ace Plc BAe 146 -300, VH- NJF. Occurrence b rief no. 199702276,” Au stralian Transport S afety Bureau, Canberr a, Au str alia •Lipscomb, J; Wals h, M; Caldwell, D; et al (1995) “Inhalation toxicity of vapor phase lu bricants” AL/O E - TR - 1997 -0090, US Air Force Arms trong Laboratory, Occ upational an d Environmental Health Dire c torate, Toxicology Divisi on, Wright-Patterson Air Force Base, O hio • Kelso, A G; Charlesworth, JM; and McVea, GG (1988) "Contamination of environmen tal control syste ms in Hercules aircraft: MRL -R-1116, AR- 005 -230," Australian Government Departmen t of Defence , De fence Science and Technology Organisation, Melbourne, Australi a • Rayman, R B and McNaughton, GB (1983) "Smoke/fumes in the cockpit" Aviat. Space Environ. Med., 54(8): 738 - 740 • Paciorek, KL ; Nakahara, JH; Kratzer , RH (1978) “Flu id co ntamination of aircraft cabin air and breathi ng oxygen” SAM - TR - 79 -34, R eport by Ultr asystems Inc. for US AF School of Aerosp ac e Medicin e, Aerospace Me dical Division, Broo ks A ir Force Base, Tex as • Crane, CR ; Sanders, DC; End ecott, BR; et al (1983) "Inhalation toxicology: III. Evaluation of the rmal degradation of products fr om aircraft and automobile engine oils, aircraft hydrau lic fluid, and mine ral oil," Aviation Medicine Report FAA AM - 83 -12, Civil Aeromedical Institute, US Fede ral Aviation Administrati on, O klahoma City, Oklahoma • Treon, JF; Cappel , JW; Cleveland , FP; et al. (1955) “The toxicity of the products formed by the thermal decomposition of certain organ ic subst anc es.” Am Ind Hyg Assoc Quarte rly, 16(3): 187 - 195 E v en though it is not unusual f or the NTSB t o include the F AA and manuf actur er s in acci den t in ves tig a tions, both the poorly -c onceiv ed design of the air sampling trials and the sw eeping c onclusions, sug g es t tha t c ommer cial c on flicts c on tr olled this pr oject. Ov er vie w 1. Who sa y s oil fumes can c om pr omise fligh t saf e ty? 2. NS TB in ves tig ation in to 10 cr ashes (including highligh ts of acc ide nt r eports - 1978, 19 79) 3. Mor e r ecen t e x amples of compr om ised fligh t saf e ty (brie fly) 4. R ec om mendations Ex amples of mor e r ecen t acciden ts c aused by fumes but not in v es tig a t ed: • But tha t w as the 1980s! W e g ot a lot of things wr ong! Sur ely , things ha v e chang ed? • AF A filed r eques ts with NT SB t o in ves tig at e fume ev ents that qualified as acciden ts (per 49CFR83 0.2) in Jan. 2010, Oct. 2018, and July 2019. • The airlines didn’t r eport these ev en ts t o the NTSB , ev en though the y w er e r equir ed t o do so. (AF A submit t ed FOIA r eques ts f or all r elev ant r ec or ds, but w as t old tha t ther e w er e no r ec or ds.) • AF A r eques ts f or in v es tig ations wer e unans wer ed. E v en though the solutions ha ve been r ecogniz ed f or decades… Ov er vie w 1. Who sa y s oil fumes can c om pr omise fligh t saf e ty? 2. NS TB in v es tig ation in to 10 cr ashes (including highligh ts of acc ide nt r eports - 1978, 19 79) 3. Mor e r ecen t e x amples of compr omised fligh t saf e ty (brie fly) 4. R ec omm enda tions R ec ommenda tions 1. Congr ess incr ease NT SB funding t o enable them to hir e mor e st af f to i n ves tig a te mor e acciden ts, includi ng those c aused by fumes – not “jus t ” the big disas t er s. 2. NTSB r eopen the 1984 r eport and r evie w/upda t e the conclusi ons based on wha t w as known about oil f umes/fligh t saf e ty the n, and also c onsider ing the dat a and r eports publishe d since then. 3. NT SB issue r ec ommenda tions t o the F AA on necessary actions to minimiz e the fligh t saf e ty impacts of e xposur e to oil fumes. Ex ample of c ompr omised fligh t s a f e ty on a c ommer cial fligh t: Jan. 16, 2010 • On Jan. 16, 2010, Cap t ain Da vid Hill and Fir s t Of ficer Mick F owler w er e impair ed dur ing the descen t phase of US Airw a ys fligh t 1041 because they w er e br ea thing oil fumes. The y w er e t ak en of f the air cr aft on s tr et cher s and tr ansport ed to hospit al along with the impair ed c abin cr ew and eigh t sick passeng er s. • The air cr aft mechanic al r ec or ds c onfirm t ha t oil c on t amina t ed the bleed air during tha t fligh t and the air cr aft had a his t ory of smok e/fumes. Compr omised fligh t saf e ty: Jan . 16, 2010 • In July 2010 , the F AA t ook Cap t ain Hill’ s license bec ause he w as not fit t o fly . Compr omised flight sa f e ty: Jan. 16, 2010 • In Jan. 2013 , the airline denied his w ork er s’ c ompensa tion claim. • And in Dec. 2019, in despair , he shot himself in the head. • He los t his lif e. The liv es of the other cr ewmember s ha ve been damaged – all e xtr emely sad. On subjec t of flight saf ety , Cap t ain Hill and his Fir s t Of ficer w er e impair ed dur ing descen t and landing. They said tha t the y c ould easily ha ve t ak en down the en tir e plane with the cr ew and 216 passeng er s on boar d. • If the y had done so , wha t would t he acciden t r eport sa y? Pr obable c auses? “Unde t ermined” , “unknown” , “miscell aneous” , et c. I think it w ould sa y some thing lik e this: Tha t the air cr aft had a his t ory of fum es. Tha t the pilots made mis t ak es – they s t opped r esponding t o A T C, f or g ot to put do wn the landing g ear . Ther e w as oil r esidue on the inside of the E CS. Som eone m a y ev en pr opose a h ypothesis t o the NTSB. And the pr obable c ause w ould be unde t ermined. Wha t is the c or e messag e to the NT SB , F AA , and indu s try? Put fligh t sa f e ty be f or e c os t sa vings. Judith A nder son , MSc CIH Indus trial Hy gienis t Air Sa f e ty , Health, & Security Dept. AF A-CW A , AFL-CIO judith@AF Ane t.or g – (001) 20 6- 932 - 6237 Thank you f or your at t en tion. Aircraft Cabin Air Inte rn ational C onfe rence 20 21 (ACA 2021) – Pro ceedings Conference : Online, 15 - 18 March 2021 Conference Di rector: Tris tan Loraine Publisher: London, UK: GCAQ E (https:/ /gcaqe. org) Editors: Dieter S chol z, Susan Micha elis How to cite th is pa pe r (ISO 690, Harvard): BREHAN Y, Frank, 20 2 1. Air Quality: The S tate of Standards. A ir craft C abin Air I nternation al Confe rence 2021 (Online, 15 - 18 Mar ch 2021) . London, UK: G CAQE. Availa ble from: htt p s :// doi.or g/10.5281/zeno do.555249 4 Revie w proc ess: Ed itorial review . Previ ous pr esentation : BREHAN Y, F ran k , 2021: The State of Standar ds - Cabin Air Q uality . Blog . Ava ilable f rom: http://frankbrehany.com/ blog/the - state - of - standards - cabin - air - quality . Archived at: https:/ /perm a.cc/H Z7M -C5UN . – Listen to: https:/ /youtu.be/HMslA3jdY Ak . 1 Air Quality: The State of S tand ards BRE HAN Y, Fran k Independent Consumer Cam paigner & Commentator E-M ail : F rankBrehany@icloud. com Copyrig ht © 2021 by author This w ork is licensed unde r the Crea tive Com mons Attribution 4.0 Internati onal License (C C BY) . http s :// creativecom mons. org/licenses /by/4. 0 Ab str ac t Purpos e: This wo rk provides an overvi e w, fro m a Con su m er per sp ectiv e, on how the proble m of Cabin Air Q uality is being ad dress ed through the d evelop men t of an Inter natio nal Standar d. The author is neit her a scientist, eng ine er nor pilot, but has had to engage wit h eac h of th ose disc iplin es and det ermine h ow a bett er outcome can be achiev ed fo r ordinary a irline pa sseng ers an d for th e air that th ey br eath e. The paper conclud es on ha rd - law versu s so ft - la w and the serio u s is sue s that n eed to be a ddresse d, bec au se the is sue of contaminated Cab in Air and Standards must su re ly be at the cros sroads? Methodology: Th e author’s ext ensi ve exp er ienc e in the work of Standardis ation and dealing wit h direct Consumer conta ct, across two continents , has been crit ically exa min ed to pro vid e an o vervie w and an alysis of the current bene- fits for Con sum ers. Findin gs: The i ssu e of contaminated Cabin Air has develop ed an Inte rnational " Standar ds " circus wher e politic s, com- mercia l p olitics and the possi bility of sol ut ion s, co nstantly challenge the cha llengers. T here is a difficu lty in a rule - ba sed Standards - m aking syst em that fa il s to adequate ly depl oy methodology and define adequately what constitutes a c on sensu s. This paper highl ights t hose diffi cultie s and rai ses a number of challeng es t hat if resol ved, may deli ver a Standard of benefit to an Industry and the occupant s of an aircraft. The alt ernati ve is a hard - law soluti on. Resea rch L imitation s: Thi s paper is limited to the work, view and opini ons of one inde pendent Consumer C ampa igner . But, t he subje ct matter is also l imited by the scan t attention paid by many European Consu mer Organ isation s to th is work. Curre nt EU Standardisation Regul ation only recognises Co n sume r " Establishm ent " Organ isations. Practical I mplication s: Thi s pa per has impo rta nt metho dol og y implicat ions for th e future of European Standardisat ion and the potential for its work on contaminate d Cab in Air. It also raise s important que stions about the s tate and status of Aviation Regu lation in the EU. Social Implica tion s: Th e com men tary in this paper has the potential to al ert the EU Consu mer Organisation Indus try as to the complexity of is sue s on contaminate d Cab in Air, and the pro cess of achie ving C onsu mer prot ection s eithe r through hard - law or soft - la w. It a lso h as the potential t o ra ise a war ene ss am ong st Con su mer s globally as to the nat ure of Cabin Air Qualit y. Air Q ualit y : The State of St andards 2 Value and Origi nality : The ori gina lity of this paper is founde d in the exp erien c e of its aut hor, and its abil ity to high light key i ssu es that h a ve the pot ential to lead to a solution to the long - standing problem of contaminated air within air- craft . Keywords cabin air quality, aircraft, t r a ve l , holidays , flight, consume r rights, co nsu m ers, air p as seng e rs, a ctivis m 1 Introdu ction My fi rst foray into Cab in Air Q uality came in 2006, wh en I met a group of pa ssen ger s who had exp erien ced a probl em during their flight from the UK d own to Flo rida. A number of passen g ers wer e ove rco m e by fu mes on thei r flight and suff ered w ith p o st - fligh t proble ms, not just in th eir r esor t , but wh en t hey r etu rned to the UK. Some su ff ered wi th ner ve or con centrat ion problems, other s spoke of respirato ry i ssue s; a sma ll nu mb er su ffer ed wit h long - ter m h ea lth - pro blems . I qu ickly b ecame en gaged wi th the pilot and flight - attenda nt commu nit y and r ealis ed th at this had b een a m ajor is- sue o ve r man y y ear s, that h ad affec ted so man y air crew, and as I was to di scove r, so ma ny pa ssen ger s. W hilst scien ce had evad ed my own ea rly educati on, I had to acquire new skills, j ust to be able to maintain a po sition in this n ew con- ver sat ion ; I now know more about the worki ngs of a jet - engin e than I do of the engine in my car! I also di scov ered that within the Con sumer r ep resen ta tio n community, there w ere fe w, if any, who wer e aware of the phenom ena of contaminate d air in a ircraft. Along wit h my new coll ea gu es, I explo red the route to ‘hard - law’ (tha t is a law that obliga tes a State, an indivi dual or company to carry out a particula r act), but I qu ickly d iscovered that in the field of Aviation , wh il st t here ma y be structural ‘hard - la w s’, the majority of ‘ o bligati ons’ wa s to be found in the mechanis m of ‘so ft - l aw’, structured through Standar ds. Such Standards are generally voluntary and not - bindi ng, the knowl edg e of which was m et wit h incred ulity by pa sseng er s aff ect ed by a fu me e vent , a fter r eturni ng from t heir holid ay in Bulgaria. I a lso r ea lis ed th at ma ny of the Sta ndards created w ere fo rmed in the company of a Regulator and Industr y and som etim es with non - aviation ‘establ ish ment ’ bodies ; I rea li sed that the wid er cohort of aircrew and pa sseng er s wer e not ably abse nt from the conver sation. So, I found myself r ep resen tin g p assen ger s in the Un ited States and within Eu- rop e, br inging to the ta ble the ex peri en ces of rea l p eop le, th e ones wh o sit at the back of the aircraft, an d thei r ob vi- ous need not to en ter i n to an env ironme nt that may a dvers ely affe ct th em. In this paper, I am goi ng to ta lk about my exp eri ence s with Cab in Air Q uality and the State of Standar ds; the Stat e being the princip al backer of Standards work and the actual s tate of S tandards . 2 So why Stand ard s? Standar ds are viewed as consens ual solution s to the myri ad of engin eering and technica l is su es that can a rise on a ir- craft . Standards are gen eral l y seen as a so ft er option against hard l aw, in an e ffort to cr eate a wi der co mplianc e and perhaps i nnovation. They are attractive to legi slat ures because they pot entially take the hard work ou t of law - making. Standar ds are ge nerally non - binding and have no legislati ve fo rce, but t hey are potentially p ersu a sive on complian ce where a co mplaint or proble m arises on an a ircraft. Th e a rgu ment ma de by Ca mpai gners wa s t his: “If we have no im- mediate o pportunity to cr eate har d obligatory la w, then we should as impor tant stakehol ders, have a seat at the Standards top table to dir ect and i nfluence t heir content” . Aircr aft Ca bin Air Internat iona l Conference 2021 3 As a re su lt of my wo rk wit h C onsu mer s, I beca me en gag ed in the wor k of Standar ds, initially in th e United States 1 , along with wo rk in th e UK 2 and in Europe 3 . 3 The Cult ur al Divi de The exp eri ence in the United States is interesting, t his is bec ause I bega n to recognise the cultural di fferenc es that exist bet we en the USA and Europe . This ran ges from attitu des toward regulation/d eregu lation , to how busin esse s are run a nd how employ ees of tho se busine ss es en gag e with workplac e issu es. It has been vita l to unde rsta nd th ese dif- ferenc e s bec ause th ey hel p to in form wh y positio ns are ta ken and th e potential route to engag ement ; it has been a media tion ma ster cla ss without the forma l trainin g! To give you an example of so me of the difficulti es, there ar e times wh en I have fel t that th e Con sumer point of view has been d rown ed out. But then if you are suggesting th e introdu ction of the Prec autionary Princip le 4 in to an Ameri- can Standard, yo u’d b etter be prep ared fo r the almos t apop lectic rea ction to your propos al. 4 The Use of Gro und- Ba sed Thresh olds Anothe r exampl e can be fou nd with in the de bate on g rou nd - b ased thre shol ds; their pote n tial use in the aircra ft envi- ron ment provides for an ab stract debat e. So for examp le, it has been o ffer ed that current threshol ds do not de li ver considerat ion of the ‘em ergenc y’ condition s that ari se fro m a fum e even t. It h as been sugg ested that the nature of the ‘emer gency ’ lea d s to diff eren t consid erations, and th at current thre shol ds s hould reflect su ch an ‘emer gency ’, adopt- ing the levels (whi ch woul d rep resen t an increase found in the curre nt Standard) , in lin e wi th the US Dep artm ent of Energ y, Healt h, S afety & Securit y’s, Protective Action Criter ia (PAC) em erg ency thre sholds 5 . If we follo wed that lo gic, for exa mp le, the Carbon Monoxide ( C O) thres hold cou ld in crease th reefo ld fro m the current state d le vel s; is this ac- cept able? Now I ha ve deliber ately cho sen CO because I wond ered wh at migh t be the m otivati on behind this move? I could be wrong, but the Un ited States may pas s/im plement a Cabi n Air Safet y Act (2 019) 6 (current ly it is passing through the US Con gre ss ). With in that Act th ere is a requ ir ement that wou ld ob ligate a irlin es to fit Carbon Monoxide (CO) sen so rs. I can s ee the con cerns of airline s, worri ed that CO se nsor s ( with a low thr e shol d li mit), coul d deli ver re- peat ed warni ngs which may a ffect th e viability and operations of that aircraft. It there fo re ra ises the point; would th e proposed increase in the CO thre shold level within a Standard, e nsure th at the senso r wou ld not be activ ated so of- ten; how does that b enefi t the occupant s; do airlines alr ea dy know how much CO is present on any given flight? 5 The Eu ropean E xper ien ce Rememb er , standar ds - m aking sh ift s debate a wa y fro m an y ‘hard la w’ req uirem ent s and has deli ver ed a glob al st and- ards - circus, wh ere we cr iss - c ro ss ti me zones to del ive r documents that hopefully provi d e valu e and fai rn ess for all. In Europe, as ca mpaigners, we chal lenged the orthodoxy of a publishe d Indust ry st andar d, as not reflectin g the reality of flight nor in d eed the particip atio n of a wide r stakeholder cohort. That standard wa s over turn ed and n ew work bega n in 2015 to crea te a European Standard. In th e beginn ing, it was difficult , with both sid es entr enche d, but European politics always deli vers on en gagem ent and con sensu s. In 2020, des pite the challeng es of COVID and over 1,100 P ublic comm ents, we pr oduce d a d ra ft Standard of val ue: C EN prEN 17436 7, 8, 9 . Th e docume nt d eliv ers series of mech anis ms 1 https://www.techstreet.com/ashrae/standards/ashrae - 161 - 2018?produ ct_ id=2001169 2 https://standardsdevelopment.bsigro up.com/committees/502 56465 3 https://w ww.cencen elec.eu/europea n - standardizat ion 4 https://eur - lex.europa. eu/LexUriS erv/Lex UriServ.do? uri=COM:20 00:00 01:FIN:E N:PDF 5 https://w ww.energ y.gov/ehss/ protective - action - cri teria - pac - aegls - erpgs - t eel s 6 https://www.cong ress.gov/bill/116th - congress/house - bill/2 208 7 https:// perma.cc/ S7AD - 5G7J Air Q ualit y : The State of St andards 4 (or a hierarch y of controls) al l under the watch ful umb r ell a of the Precautionary Princi ple. Thi s document does not conta in thres holds , bec ause that is what ALL the stakeholder s agr eed we should do, we also wen t beyond the pass/ fa i l criteria ar gu ment . Our wo rk d eliv ered due car e, due diligence, along wit h co n sen su s fr om every single s ecto r in thi s deb ate. The current draft Standard presen ts the very be st of solu tio ns, wh ere fo rmal European regula tion h as thus far failed . Throug h this pro cess in 2020, we bega n to see th e emerg enc e of a press narrative that demo nst rated that so me wish ed to r esi le fr om the previous position of con sen su s. Equally, dur ing the p roces s of the la st t wo y ear s, so me ex- tern al let ter s wer e rec ei ved on cab in air quality. Some of t ho se lett er s w ere brought to our atte ntion; som e I have subs eque ntly b een ma de aware of. Whilst I could certainly provi de exten si ve com men ta ry on the issues that were rai sed, I will not do so at th is time si mp ly bec ause I wish to resp e ct the fac t that t hey ap pear to be p rot ected by p ri va - cy. But from wh at I have see n, in my o pinion, some conta in mat ters of impor tant public inter est warranting at lea st som e for m of deb ate. Currently this is a matter for o th ers to dea l with ! Despite t hese in t er ven tio n s, th ere was a clear palpable fear fro m som e that t his Standard would enter the lexicon of Aviation la ws, but given t hat the many l aws th ey refer to as “regulation ” suc h as CS (Certificatio n Specifi cation s) 10 , AMC’s 11 (Acceptab le Mean s of Compliance ), AltMoc’ s (Alterna tive Means of Comp l ian ce) , are in fact vol untary, non - binding a nd, h a ve no legislati ve force, th eir fear is somewh at redundant. As COVID ent er ed our li ve s, so me wa nt ed to sus pend the w ork. At the end of 2020, wh en ma ny exp ected th at the d raft Standard would go out fo r a for mal vo te, pot entially leading to pub lication , we all exp eri e nced an in teresti ng co mmen t ar y and so me su rp ri se s on the outcome of our expectatio ns. A deci sion wa s mad e, not by t he expert s on the Standar ds Commit t ee, but for and on beh a lf of the experts, as to what woul d n ext happen to the draf t Standard a nd its future direction of tr avel, leadin g to yet another Public Enquiry. The argu ment s I hear d to support this action st em med fr om so me wanting to give t h o se ‘not in the room’ the oppor tunity to subm it their o wn points of view or, a lack of cons ens us or, a claim of reliance on the so - called ‘Salon’ case as rea- son s for not s ending the docum ent out to member states fo r a d ecision toward publica tion. The ‘not in th e room’ arg ument simply fails bec ause av iation man ufa ctu rers and a irlines ha ve all b een act ively en - gaged in th e global - standards - circus, th ey wou ld ha ve to be social ly isolated not to have h eard and rea d of the exi st- ence of this European Co mmit tee; in any event , th ey had verifia bl e rep re senta tio n fro m the early days on this Com- mittee . A claim for a l ack of conse nsus also fails beca use the facts sp ea k for th emsel ve s; we had come to t ru st eac h ot he r and had defin ed a clear p ro ce ss that d eli vered for a ll voi ce s through due diligence. 6 The Salo n- Cas e 12 Argument The Salon ar gumen t demo nst r ated a m is under standi ng of this i nter estin g Standards case, which wa s essentially a dis- pute between t wo standards technical co mmi tte es. One commit te e claim ed that the oth er’s published s tandard shoul d not sta nd becaus e some of its measu re s needed to be carried out by qual ified p eop le. H owe ver, in my opinion, the important argumen t cha llenged that this publi she d standard failed to protec t the hea lth and safety of EU Citizens. The ca se simply had no analogy to our p resent circu mstanc es becaus e of the conse nsual na ture of our work and of the exten siv e debate on safety le ading to th e univer sal a ccept a nce of the Pre cautionary Principle. As we all struggl ed to deal with this new d ir ection of trave l, I a l so d isco ver ed t wo ot her important issu e s. 8 https:// eurecca.eu/p ost/eu ropean - ai rcrew - passengers - welcom e - completion - standard - aircraft - cabin - air - qu ality 9 https://www. eurocockpit .be/news/s upport - new - standard - cabin - air - quality 10 https://www. easa.europa.eu/faq/19026 11 htt ps://www.ea s a.europa.eu /document - library/a cceptab le - means - com pliance - am cs - and - alternativ e - means - compliance - a ltmocs 12 htt ps://www.to p - normy.cz/users /files/procesy - tn/CEN - C ENEL EC - Refi t.pdf (Search for ‘Salon’) Aircr aft Ca bin Air Internat iona l Conference 2021 5 7 Fuel Tank Ine rtin g System The fi rst rel ated to the Fuel Ta nk Inerting Syst em 13 , 14 , d eliverin g a separati on of bl eed - air gase s and compounds , so prov iding an inert gas fo r the fuel tanks on aircra ft. It ca u sed me to ask, if this separation technology (to remo ve chemical compounds or h arm ful g ase s) already exi st s, th en why had this not b een d iscu ssed since 2015 ? 8 The Jam es Ell io t Case The s econ d point relate s to a case that cam e befo re the Eu ropean Court of Ju sti ce in 2 017, which decl ar ed that ma n- dated/ harmo nise d Standa rds, attached to Eu ropean Regul ation , shoul d also be consid ered as law. This d ecision has already had a profo und effect on the European Standar ds world and I susp ect t her e is so me reti cenc e fro m Co mpa- nies wh o had b een given up - to - now, free - rein to defin e thei r operations . It got me thinking . The Trea tie s of the EU prov ide a di vi sio n of labour and co mpeten cy fo r the b enefi t of the Union and the Single Market. One co mpeten cy is Aviation. E ASA has be en give n that co mpeten cy by the EU to make re gulatio n. Th erefor e , if you fol low the logic of this case, the ‘standards ’ attached to for mal r egulation , th ose being CS’ s, AMC’s & AltMo C’ s, must ther efo re be logically mand ated and harmonis e d, and should surely now be classed as forma l la w, wit h all th ei r appare nt imperfe cti ons ? In my opinion, it p resent s an opportuni ty for Tra de Unions and Consumer Organisations acros s Europe , who should begin the convers ation and challenge the status of European Aviation Standards , utilising the argumen ts and logi c of this ca se (James Elliot Con stru c tion - A ggregat e - Co uld the c ou rt adjudicate on a harmonis ed standar d? 15 ) . Would this not crea te a sen se of purpose and legal certain ty; wha t ab out benefi t to pilot s and cab i n - cr ew and ultimately the pa sseng ers ? 9 Pres su re Point s In conclu sion, we are now fac ed wit h a number of pre ssur e points : 1. Recogni sing the exten siv e risks that ex ist in st andards - mak ing a gainst the risk s faced by the occ upants of aircraft (Ve sted Intere sts/app lication of ru les); 2. In Europe, f inding a way to re store con sen su s, tr ust and onc e again d eter minin g ethical i ntenti ons; 3. As we sub scri b e to standa rds - making rules and eth ic s, how we can ensure that the work g uara ntees p roc es s, en - force ment , ov ersi gh t, co urage or sta bility ? 4. Will we onc e again ha ve to respond to the desire fo r a pe rformance - ba sed or thresholds Standard ? 5. Should we claim a ne ce ssary & prop erly formed m ethodology, clear & open anal ysis and a recognit ion of a wid er European Unio n pr ocess ? 6. Will thi s wo rk l ead to arg uments witho ut end when all thought that such argu ment s had b een reso lve d by con - sensu s ? 7. From a pe rsonal persp ect ive, if a proc ess produces difficult ies that could ultimate ly del iver d etrim ent to Con su m- ers, is it right to conti nue to legitimise that pro cess ? Thes e are dif ficult questions but they are now accomp an ied by th e need to car ry out a continual risk a sse ssm ent of any standar ds - m aking pro cess ; it is no lon ger an option not to risk assess t his work. 13 https:// www. faa.gov/regu lations_policies/ rulem aking/comm ittees/docum ents/media /ECfthw gT1 - 1231 998.pdf 14 https:// www. collinsaerospace.com /what - we - do/Business - Aviation /Pow er - Controls - Actuation /Actua tion/C omposites/ Fuel - System s/Fuel - Tank - Inerting - Systems 15 http://curia.europa.eu/juri s/liste.jsf?l anguage=en&num=C - 613/14 Air Q ualit y : The State of St andards 6 10 Conclus ion Looking forwar d, I think th ere are sever al im med iat e chall en ges ahead: 1. The ch all enge of the appropriate ness of g round - based thres holds again st the failur e to properly define the uniquene ss of the aircraft en v iron ment ; th ere n eed s to be a hierarch y of argu ment ; 2. EU Aviation law/standards provides a pres umpt ion of complian ce, wh ich i s a flawed reg ulatory co ncept , beca use it imp orts th e ‘ben efit of the doubt’ argu ment, res oundly r ejected by the Precautionary Principle - is this the ult i- mate d irection fo r thi s Standa rd? And finally ; 3. We as Ca mpa igner s have in my opi nion taken our ey es off the ‘regul atory ’ ball, and I hope other s will join me in creating a forma l European R egulation on Cab in Air Q uality . In my opinion, the State of Standar ds is now at a crossr oa d s, what we do next is i mpor tant for all. Ab o ut th e Author Frank Bre hany. I am a dual - Citizen, on e of w hich d eli ve rs a long - standing European Citizenship . I am a m edically re - tired Police - O ffi cer and q ualified in 1997 as a practising Sol icitor, working initially in fo rmal legal pra ctice, this lea d to owner ship and manage ment of a National Consumers Organ isation. My int erests in L aw co ver s not j ust Con sumer Law, but also th e pr ob lems found within Consu mer Contracts, European Law, Hum an Right s and National and cross - border solution s to Con su m er pr obl ems. I h ave ext en si ve me d ia exp er ienc e, and com ment on Lega l is sue s for Con- sumer s, Tra ve l Trends and the Trav el rela ted problem s exper ienc ed by Co nsu m ers. I continue as a sel f - funded practising so licitor, not currently working in Legal Pra ctice, but I maintain my comp eten- cy as re quir ed by the Solicitors Regula tory Auth ority of Englan d and W ales. I apply my legal train ing and ex perien c e, to h elp d evel op s olut ions within the Standar ds - m aking and Political en vi- ron ment s. I have never be en a memb er of any polit ical party or groupi ng an d I volu ntarily subsc ribe to the Nolan Prin- ciples for Standards in Public Li fe. My legal wo rk ha s alw ays been about the day - to - day Consu mer or Victi m - rel ated is sue s, but now I work in argu ing both pra ctically an d polit ically for ch ange on Cab in Air Q uality . I ha ve now publis hed a book for Co nsu mers to ra ise awar ene ss of this is sue : "G a sp ers: Clean Air for Pass e ngers?" 16 16 htt ps://www.a mazon .com/dp/B 09 B1L1PT S Aircraft Cabin Air International Confer ence 202 1 (ACA 20 21) – Procee dings Conference: Online, 15-1 8 March 2021 Conference Director: Tristan Loraine Publisher: London, UK: GCAQE (https:// gcaqe.org) Editors: Dieter Scholz, Susan Mi chaelis How to c ite this paper : BURDON, Jonathan, HOW A RD, C. Vyvya n, MICHAELIS, Susan, 20 21. Aero toxi c Syndrome, the Heart and Organophosphates. Aircra ft Cab in Air In ternational Conference 202 1 (Online, 15 -18 Ma rch 2021) . London, UK: GCAQE . Available from: https://doi.org/10.5281/zenodo.6383345 Autho r contrib utions : Jonathan Burdon wrote the pa per and all authors contri bu tted to the content. Review p rocess: Editoria l review. T he corresponding author is marked with *. Re lated presentatio n: https://doi.org/10.5 281/zenodo.47304 09 1 Aerotoxic Synd rome, th e Heart and Organophos phates BURDON, Jon athan 1* , HOWARD, C. Vyvya n 2 , MICHAELIS, Susan 3 1 Respiratory Physician, East Melbourne, Australi a 2 Centre for Molecula r Biosciences , University of Ulster, UK 3 Occupational and Environment al Heal th Research Group, Uni versity of Stirling/ M ichaelis Aviation C onsul ting, West Sussex, England E-M ail : jburdon@bigpond,net. au Copyright © 20 21 by author(s) This w ork is licensed under the Creat ive Commons Att ribution 4.0 Int erna tional License ( CC B Y ). https:// creativecommons .org/licenses/by/4 . 0 Abstract Purp ose: The p urpose of this presentati on i s to increase the awaren es s of the cardiac ef fects of OP toxi city in aircrew exposed to FE s. Two case vi gnett es of aircr ew experiencing OP toxici ty as a result o f FE exposures are presented as an introdu cti on to the subject of the p resent paper. Keywor ds aerotoxic syndro me, card iac dis ease, or ganopho s phates 1 Introduction Aeroto xi c Syndr om e was first des cribed by W inder and Bal ouet 1 in 2000 to describe a c oll ection of p redominantly neur ologi c and respirat ory symptoms ex perienced by ai rcrew followi ng exposure to py roly sed jet engine oil leaki ng into t he bl eed ai r and t hus contaminati ng th e ai rcr aft cabi n ai r (fume events – FEs) . These fumes contai n a cocktail of volatile organic hydrocar bons many of whi ch are kno w n t o be toxic i ncluding organop hosphates (OPs). The latter are included i n jet engi ne l ubricating oil s as an anti -wear additi ve. Si nce the o rigi nal descripti on, medical complai nts af- fecting all organ s ystems have been recor ded foll owing a FE 2 . The effects of ex posure may be transient, pro longed and somet ime permanent. T he term and exi stence of ‘ Aerotoxic Sy ndrome’ is critici zed b y s ome group s b ut the a u- thor s have used in the present context as it is the term used in the original pub li cation 1 . 2 Case presen tatio n s Case 1: A 34 year ol d mal e pi lot wh o had been ex posed to three FEs over a th ree mo nth period ab out two y ears p rior t o presentation was seen complaining of s ymptoms of nau sea, li ght-headedness, fogg y thinking, cognitive dys func ti on, fatig ue tremor, grey ski n, eye i rritation, cough, b reathl essness and pal pitati ons. The l atter increased w ith exercis e. A detail ed car diac a ss essment showed a r apid irregular hear t rate at r est with frequent ventricular ectopic beats. Aerotoxic Syndr ome, the Heart and Organophos phates 2 Case 2: A 41 y ear old femal e fl ight att endant pres ented followi ng a sig n ificant FE event complai n ing of mil d headache, nausea, dizzi ne ss, cou gh, breathlessnes s an d palpitat ions. She w as als o suffering f rom balance a nd g ait di fficulties, poo r short-term memory and cognitiv e impai rmen t. Her diz ziness, particul arly on standing up, and palpitati ons con- tinued and when exami ned fo ur years later a diagno si s of Postural Orthostatic Tach ycardia Syndrome (POTS) was made. 3 Organophospha te poisoning – gen eral comments Organop hosphate toxi cit y is we ll known in the general co mmunity and i s usuall y the result of poisoning followi ng their use in ag ricultur e (pesti cides and her bi cides) but accidental and s uicidal pois oning s are not uncommon. Inhalat ion is the usual portal of entry but OPs may al so be absorbed t hrough the ski n, conjunctivae or inges te d . Wit h these ex po- sures cardiac t oxicit y i s c ommon an d us ually manifested by EC G chang es, myocardial damage wi th impai red cardiac func tion, abnormal cardiac rhythms some of w hi ch are serious enough to cause death. Other t oxic effects of OPs in- clude cough, b reathles sness, chest pain/tightness, salivation, tea ring, sweating, nausea, v o mi ting, diarrho ea, head- ache, vis ual disturb ance, confusion and cogni tiv e impairment, tremor, di zzi ness, loss of bal ance and someti mes coma. Most poisonings in the ag ricultural and commu nity follow l arge and usuall y accidental e xposures and s erious car diac abnor malit ies are frequ ent 3 ,4 . Death fr om acc iden tal and suicidal intent are well r ecognised 4 . Toxicity i s largely related to myocar dial irritability manifested by cardiac rhythm disturb ances, su ch as sl ow , rapid (palpitat ions) or i rr egular hea rt rates . Elect rical abno rmalit ies of the heartbeat are al so c ommon, for exampl e ST - T wave changes and Pr olonged Q - T Syndrome, the latt er which may prompt l ife th reatening arrh yth mias, such as atrial fibrill ation, ventricular t achycard ia or fibril lation and T orsad es de Pointe wit h the l atter tw o causi ng death if not pro mptly treated. 4 Aerotoxic Syndro me, the h eart and organophosphates OP cardiac t oxici ty has l ong been rec ognised in the non -aircraft sett ing but i n the fume ev ent s etti ng it att ract s l ess consider at ion and i s in frequently recognised by the medi cal pro fessi on. The reason for this i s pro babl y due to OP con- centrations being sig nificantly smaller in cabin ai r after a F E in c ompar ison t o that found i n ag ricultural and industrial settings. FE may al so af fe ct pass engers and very low ex posur es to the OP tri -o-cresyl phosphate ha ve been reported 5 . As a result of th e smal l er cab in air OP co ncentrations, cardiac abn ormali ti e s are much less frequ ent . Whil e there are no sy stematically documented rev iews i nt o the al terations in heart rate a nd/or blood pressure afte r FEs, cardiac abn ormali ti e s repo rted by aircrew aft er FEs have been docu me nted 2 . Higher rates of heart disea se have been repor ted by fli ght attendan ts exposed to cabin air con taminants i n one s tu dy sugg e st in g that they may be related 6 . However, this ass ocia tion was not co nfirmed in a later study 7 . In t he community setting and at the patholog ical level, patchy myocard ial and pericardial damag e has been rep orted in acute OP pois oning as a res ul t of direct ca rdiac toxici ty and may be a factor i n seri ous ca rdiac complicati ons. The author s w arn that thes e fi nding s may not result in ECG o r ec hocardiogr aphic changes and, for t his reason, cardiac monitoring is warranted 8 . An ai rcr ew postmortem s tu dy i dentified l ymphocyt ic myocard iti s, which was thought to be related to O Ps 9 . A UK c or- oner referring to other aircre w postmortem cases noted that, i n two cases of y oung fit ai rcr ew, there w as evi dence of lymphocyti c myocarditis and periphe ral nerve dama ge 9 . In another re por t, a l eft v entricular myocar dial biopsy showed the histol ogi cal features of a toxic myocarditis 10 . For obvious reasons, as car diac di agnosti c procedures, e.g. Aircraft Cabin Air Inte rnational Conference 2021 3 ECG, echocar diogram recordings, st ress tests and myocar dial perf usion s ca ns , are no t routinely undertaken prior to o r in - flig ht , the p re-mor tem cardiac stat us of aff e cted p ersons h as no t been described. Thu s, i t is clear that OP exposure may lead to cardiotoxi cit y following a FE and has been s ho wn to cause rhythm dis- turban ces and my o cardial damage. A s the l a tter may be pr esent i n the absence of cl inical signs an d ECG changes , i t is important to consi der mor e detai led card iac investig a tions in all cases, par ticularly if car diotoxicity is suspected. 5 Summa ry In s ummary, OP in d uc ed cardiac t oxicity is comm o n i n the g ener al agricultural commu nity where s i gnifi can t exposur es occu r as a r esult of the use o f herbicides and pes ti cides. Present knowledg e suggests it i s l e ss frequent in as sociation wit h ai rc raft cabi n FE s bu t the cu rr e nt lit er ature is l im ited on the su bject and there hav e been no systematic studies cond ucted. Expe rience and the l imi ted literature s ugge sts that FE s may cause cardiac abnormalities and that these may be transient or long standing . Mor e studies ar e need e d. Li st of Referen ces WIND E R, C., BALOUET , J-C., 20 00 . Aero toxic Sydrom e : Adve r se Health Effects Follow ing Exposure To Jet Oil Mist Du ring Co mmercial Flights. In: Ed di ngton I (ed) T o wards a safe and Civil So ciet y. Proceedings of the Internat ional Congress on Occupational Healt h Conf erence. 4- 6 September, 20 00. Brisbane. MICHAELIS, S ., BURD ON, J. , H OWARD, C., 2 017 . Aerotoxi c Synd rome : A n e w o ccupa t ional disease  ? Public Heal Panor vol 3. pp. 198 – 2 11. ANAND, S., S. Singh, S AIKA, U.N., BHALL A, A., SHARMA Y.P. a nd SINGH, D., 2009. Car diac a bnor malities in a cute organophosphate p oi soning. Clin Toxicol, vol. 47 , pp 230 - 23 5. ROT H, A., Z ELLINGER, I. , ARAD, M. and ATSOMO N, J. , 199 3. Org anophosphates and the he art . C hest, vol. 103 , pp. 576 - 582. LIVASOVA, M., LI, B. , SCHOPFER , M. , NACHON, F., MASS ON, P. , FURLO NG, C.E. and LOCKRIDGE, O. , 201 1. Expo s ure to tri-o- cresyl phosp hate in jet airp la ne passengers. Toxicol Appl Pharmacol. Vol. 2 56 , pp 33 7 - 347. MCNEELY , E., GALE, S. , T AGER, I. , KINCL, L., BRADLEY, J ., C OULL , B. , an d HECKER, S. , 2014. Th e self-reported h e alth o f U.S. fl ight attendants compa re d to the general populati on . Environ Heal A Glob A ccess Sci Sour ce , vol. 13 , pp 1- 11. MCNEELY , E., MORDUKHOVICH, I. , TIDE MA N, S. , GALE, S. a nd COULL, B. , 2018. Estimating the hea lt h con sequen ces of fligh t attend ant work: Com p aring flight attendant health to the g e neral popula t ion in a cross - sectional study. BMC Public Health. vol. 1 8, pp 1 – 11. GEOR GIA DIS, N., TSARO UHAS, K. , TSITSIMPIKOU, C. , VARDAVAS, A. , R EMAZEE, R ., GERMANAKIS, I., TSATASAKIS, A ., STAGO S , D. and KOURETAS, D. , 201 8. Pesticides an d car diotoxicity. Where do w e stand? Toxic ol Appl Pharmacol. Vol. 353, pp 1 – 14. Old Square C hambers. Anna Roffey app e ars in inquest co n cerning the death of Matthew Bass . 2018. accessed 4.3.20 21 @ http:/ /www.oldsquare.co.uk/news -a nd-media/articles/anna-r off ey-appears- in -inques t -concerning-the-death- of -matthew -ba ss. ABOU -D ONIA, M.B., V AN DER GOOT, F.R.W and MULD ER, M.F ./A., 2 014 . Autoa ntibody mar ker s of n eur al degeneration a r e as s ociated with post - mor tem hi stopathological alterations of a n e urologically injure d pilot. J Biol Phys Chem. Vol. 3, pp. 3 4 – 53. Aerotox ic Syndrome, the Heart and Organophosphates Jonathan Burdo n MBBS, MD, FRACP , FCCP C. V y v y an How ard MB ChB, FRCPath Susan M ichaelis PhD, MSc, A TPL In t erna tional Air cr a ft Cabin Air Con f er ence, London 15 -18 Mar ch 2021 Af filiations J Burdon - St V incent’ s Pri vate Hospital East Melbourne CV H ow ard - Univ ersity of Ulster S Michael is - Univ ersity of Stirling Introduction - Aerotoxic Syndrom e • First described in 2000 by Winder and Balouet • Describes collection of predominantly neurologic and re spiratory sy mptom s in aircrew • But medical complaints af fecting all organ sy stems recorded • Caused by inhalation of py rol y s ed engine oil leaking into bleed air and then to incom ing cabin air • Ef fects may be tr ansient, prolonged or permanent • Existence and terminology criticised by some gr oups Clinical V igne tte – Case 1 • 36 yr old male pilot • 3 FEs over abou t 3 mont hs • Present ing sy mp toms: • Nause a, l ight headedness, f oggy thinking, cognitive dy sfunction, fatigue, shaki ng, grey skin, ey e irritation, cough , breathlessne ss and palpi tations • Palpitation s incr eased w ith exercise • Cardiac assessme nt: • Rap id irregular heart rate at rest, • V entricular ectopic beats • Sy mptom s continu e 2 y ears afte r exposu re Clinical V igne tte – Case 2 • 43 yr flight fem ale attendant • FE on long haul flight t o LA • Complai ned many symptoms i ncluding: • Mild headach e, nausea, dizziness • Memo ry and cognitiv e impairment • Breathlessness, coug h and palp itations • Palpitations now longstanding • Has devel oped postural or thostatic t achycardia syndrome (POTS) Organoph osphates (OPs) – General Comments Organophospha tes • Commonly used in pe sticides & herbici des • Also as anti -w ea r addi tive in gas turbin e engi ne lubricating oi ls • T ri-cresy lpho sphate know n ne urotox in • Mode of contact in OP poisoni ng usuall y : • Agricu ltura l • Acciden tal • Suici de • Ex posure by inha lation , ingestion , dermal , conjunctiva l Organoph osphate (OP) T ox ici ty • Most poison ings associ ated w ith large ex posure s • ~ 3 million + ex posure s w ith ~ 300,00 0 deaths annu ally w orl d w ide • Multisy stem tox ic ef fects including • Hea dache, para ly sis, loss of balan ce, v isual • Con fusion, cognitive impai rment, tremor , dizzine ss, coma • Cou gh, breathlessn ess, chest pain /t igh tness • Salivation, tearing, sw eatin g • Nau sea, v omiting , dia rrhoea Organoph osphates (O Ps) and the Heart (1) • Cardiotoxicity long recognised in non aircraft setting • Largely related to my ocar dial instability and rhy thm disturban ces • These include : • ECG abnormalities – • Elev ation S-T segment • Prolongatio n of QT interv al • Sinus brady cardia (slow ) & tachy cardia (rapid) heart r ates Organophosphates (OPs) and the Heart (2) • Conduction defe cts • Abnormal electr ical messaging fr om atr ium to ventr icle • Irregular heart rates • Atrial fibrillation • V entricular tachy cardia • V entricular fibrillation • T orsades de p oint • May lead to sudd en death • My ocardial damage – oedema, v ascular congestion, inflammation, blood clots, h eart failure, death Useful Refere nces: • Roth et al. O rgano phospha tes and the heart. Chest 1993;103:57 6 - 582 • Anand A et al. Cardi ac abno rmalities in acute OP poison ing. Clin T ox 20 09;47:230 - 235 OPs, Fume Eve nts and the Heart • Ex posure concentratio ns much low er than in most commu nity OP ex p osu res • VOCs w hen me asu red in ai rcraft cabin s le ss than ind ustry accepte d standa rds • Note the se standa rds do no t protect all ex posed • Ultra -fine particle s know n to ex acerb ate cardio-resp ira tory dise ase Fu me Events and the Heart (1) • Cardiac ef fects appear less comm only after FEs • Less w ell know n • May not be recognised in many cases • Largely related to my ocardial inst ability and arrhy thmias • No studies im mediately after an FE • Know ledge comes mostly from case based studies and sy s tematic rev iew s Fu me Events and the Heart (2) • Studies of aircrew have show n • Atrial and v entricular ectopic beats - palpitations • Coronary artery disease ~2.5% • Hy per tension ~25% • Chest pain/tightne ss up to 33% (include d palpitations and hy per tension) • Sever al repor ts of L y mp hocy tic and T oxic my ocar ditis Fu me Even ts and the Heart (3) Orga nop hosphates - Summar y • Cardiac tox icity common w ith significant comm unity ex posures • Current know ledge suggests it is less frequent aft er a FE • But literat ure limited • Experience and the limi ted literat ure suggest s • FE may cause cardiac abnormalities • Abnormalities may be transient or long standing jburdon @bigpon d.net.au Aircraft Cabin Air In ternational Conferen ce 2021 (ACA 20 21 ) – Proceed in gs Conference: Online, 15-1 8 March 2021 Conference Director: Tristan Loraine Publisher: London, UK: GCAQE (https:// gcaqe.org) Editors: Dieter Scholz, Susan Mi chaelis How to cite this paper (ISO 690, Harvard): BURDON, J onatha n, B UDNIK, Lygia Therese, HEUTELBE CK , Astrid et al., 20 2 1. Inves tigat ing Health an d Ex posure Circumstances of Per sons after Aircraft Fume Ev ents: A Narrative Review with Medical Protocol . Airc raft Ca bin Air I n ternational Conference 2021 (Online, 15-18 March 2021) . London, UK: GCAQE. Available from: https://doi.org/10.5281/zenodo.6383316 Autho r contr ibutions : All authors contribut ed to the paper wi thin their area of expertise. Overall re view was undertaken by J onatha n Burdn, Susan Michaelis, C. Vyvya n H oward and Tristan Loraine. Review p rocess: Editoria l review. The corres ponding author is marked wit h *. Previous p resentatio n: An earlier draft of t his paper w as presented at the Airc raft Cab in Air I nterna tio n al Conferenc e 2 019. Related presentatio n: ht tps: // doi.org/10.5281/zenodo.4730406 1 Investigating Healt h and Exposure Circum stance s of Per - sons after Aircraft Fume Events: A Na r rative Review with Medical Protocol BURDON, Jonathan 1 , BUDNIK, Lyg ia Ther ese 2 , H EUTELBECK, As trid 3 , BAUR, Xaver 4 , ROIG, Jordi 5 , C OXON , Leonie 6 , MIDAVAI NE, John 7 , PE TERSEN, Hannes 8 , HAGEMAN , Gerard 9 , SOSKOLNE, Col in L. 10 , G EE, David 11 , FURLONG , Cleme nt 12 , LORAINE , Tristan 13 , HOWARD , C. Vyvyan 14 , MICHEALIS, Susan 15 1. C onsultant Respiratory Physician, East Melbo urne, Australia 2. rec ent ly deceased, previously, DiMoPEx-Chair, University Medical Center Hamburg-Eppendorf, Institute for Occupational and Maritime Medicine, Hamburg, Germany 3. Occupationa l, Social and E nvironmental Medicine, Friedrich Schiller University Jena, University Hospital Jena, G ermany 4. European Soci ety for Environmental and Occupational Medicine, Pre sident; Emeritus University of Hamburg, Germany 5. Department of Pulmonary Medicine. Clínica Creu Blanca, Barcelona, Spain 6. C linical a nd Forensic P sychologist, Mount Pleasant Psychology, Perth Wes tern Australia 7. S ports doctor ( Speciali st or thomolecul ar Medicine), Lifemedic Bilthoven, The Netherlands 8. Facult y o f Medicine University of Iceland, Akureyri Hospital, Iceland 9. Department of Neurology, Medical Spectrum Twente, Hospital Enschede, The N etherlands 10. Professor Emeritus, University of Albert a, E dmonton, Ca na da 11. Insti tut e of Environment, Health and Societies - Brunel Unive rsity London, UK 12. Department s of Medicine and G enome Sciences, Univers ity of Washington, Seattle, USA 13 . Airline capt ain (ret) - Technical consultant , Global cabin Air Quality Executi ve, London, UK 14. C entre for Mol ec ular Biosciences, University of Ulster, UK 15. Occupationa l and E nvironmenta l Health Res earch Group, University of Stirling/ Michaelis Aviation Cons ulting, West Sussex, Eng land E-M ail : [email protected] Copyright © 20 21 by author(s) This w ork is licensed under the C reative C ommons Attribution 4.0 International License ( CC BY ). https:// creat ivecommons.o rg /licenses /by/ 4. 0 Abstract This do cument lays out a c onsensus appr oach , by internationall y r ecognised experts , to the r ecogni ti on, i n ves tigation and management o f pe rsons s uffering fro m t he t oxi c effects of i nhaling pyrolys ed engi ne oil and ot her fl uids contami- nating the air con diti oning sys tems in most ai rcraft. A best practice medi cal protocol is outl ined and a ddresses t he reco mmended actions an d inves tigations to be undertaken for thos e s uffer ing il l -health following FE s and presenting In - flig ht , imme diatel y Post -flight (with i n 1-2 days ) and l ater/subsequently (beyond 2 days). Keywor ds aerotoxic syndro me, fume events, i ll -health, treatment, medical protoco l Investigati ng Health and Exposure Circumstances of Per sons after Ai rcraf t Fume E vents 2 1 Intro ducti on Pyrolysed engine oil fumes contaminati ng the a ir craf t ca bin ai r condit i oning systems has been recognis ed and wel l docu mented since the 1950s. I t is now clear that inhalation of these potentiall y toxi c fu mes in aircraft cab ins causes il l - health. There is a clear and well documented history li nking the onset of ill health wit h fu me exposure in most cases . It is now clear t hat cumulative ex posur e t o regular smal l expo sures i s al so damaging and may be exac erb ated by a si ngle more c oncen t rated ex posure. W hil st organo pho s phates have been the mai n subject of interest , it is also cle ar that there are n umerous vol atile organic hydrocarbon s in the aircraft air sup ply, w hich are li kely, based on experience out- si de the airc raft industry , to contribute to this fo rm of ill -healt h . Assessment i s made mor e com plex because of the li m itations in looking at individual substance s in complex heated mixtures. The lack of acc eptance o f illnes s caused by expos ure to pyroly sed eng ine oil, de -icing and hyd rauli c flui d i n bl eed air and aircr aft air sup plies is like ly to be du e to lack of knowledge and clini cal acumen. The easi er f indi ng of more cli nical - ly acceptable diag nose s in unexplained cli n ical presentations is reco gnis ed. This docu ment l ays ou t a c onsensus approach, by i nternationall y reco gnis ed ex perts, to the recogn iti on, in vestig a tion and management o f pe rsons sufferi ng from the t oxi c effects of i nhaling pyrolys ed eng ine oil and o ther fl uids contami- nating the air conditi oning systems in most a ir craft. A best pr acti ce medical pro tocol i s outlined including acti ons and inves tigations fo r in flig ht, immediately po st flight and late subsequent fo llow up. The then al most completed first “ fi nal draft ” o f t he medi cal pro tocol was presented at this Conference i n 2019. Si nc e then, the authors have updated the document with comments on eme rging areas of in vest ig ation and addi tional med- ical and sc ientifi c materi a l. The aim of t he presentati on at the 2021 C onfer ence is to pro vide a n upd ate on fu rther pro gress to date t o those wh o att ended eig hteen months ago and to inform those w ho have n ot be en made awar e o f the s tatus of this wor k. The authors are aware that this manuscript has taken many y ears to write and acknowl edge that t his has been because of the mo v ing l andscape – new sci entifi c and medical i nfor mation t hat needed t o be i n- cluded and the difficulty of harnes si ng numero us ex perts who were and are already have huge demands on their time. The auth or s also recognis e t hat t here have been a n umber of G uid eli nes putting for ward recommendations for ac- tions to be u ndertaken at the time of and fo llowi ng a F E. The ter m and exis tence of ‘Aerotoxic Syndrome’ was coined by Winder and Balou et in 20001 to d e scribe the con stel la- tion of s ymptoms experienced by pe rso ns exposed t o FEs. T he term has been criti ciz ed by s ome g rou ps for a number of reasons. However, the au thors have used here as i t is the term used in the o riginal pub li cation 1. 2 Technical Matters Ther e i s a medical need to reco gnise and understand a number of t echnical iss ues that that are rai sed i n t he context of FEs. It is not g enerally understood in t he medi cal commun ity that the aircr aft cabin is a cl osed environment wit h a high human occupancy and that outs ide ai r is being us ed to fl ush t he cabin air and ass ist with pr essuris a tion. I n this regard it is di fferen t from a modern s ealed building as ai r ex change rates are greater than in comme rcial and other modern building s. This air enters the cabi n through the engi ne and may be contaminated by pyrolysed engine oil leak i ng thro ugh oil seals except in the Bo eing 747 Dreamliner which has an air suppl y independent of the en gi ne. Aircraft Cabin Air I nternational Conference 20 21 3 It is al so impor tant to recognise that ther e are no fine l ines separating those w ho wi ll experience i ll -health du ring or after a fume event an d th os e w ho are no t a ffected. T he regular defence used by i ndustry i s t hat e nvironm ental con- centrations of toxic substances are al l below industry accepted st andard s. This defen ce ig nor es the fact that thes e standards are set t o protect most persons exposed but n ot all . Furthermo re, these st andard s are not av ai lable for al l pyrolysed s ubs tances, all hav e been set for ground level and, thus, cann ot be extrapolated to the cabin envi ron ment and take no account for alti tude nor pyrolys ed co mplex mi xtures. 3 Me dical Matters The medi cal presentat ions of persons w ho have been ex posed to FEs are vari able and wel l -described in t he li tera- ture2. In summary, these i niti a lly, and consist ently, invol ve the symptoms of foggy thi nking, dizziness, recognisi ng an odo ur in the cabin, (common ly described as a ‘dir ty s ocks ’ smell), impaired s hor t -term memory and cogni tive thinking , fatig ue, headache, nausea, tremor, balance, incoor dination, breathing difficulti es, cough, chest pain, ey e, nose and thro at irritati on. M any oth er sy mptoms, wit h a delayed onset, have a lso been repor ted, but the common fa ctor th at binds bo th the acute and dela yed complaints i s th at they ar e all consi stent with volati le organic hydrocarbon an d or- ganopho sphate toxici ty. Medical management i s related to the presenti ng sy mptomology at t he time of ex aminati on and speci fic i nvestiga- ti ons will vary in each case, depending on s pecific technical and indivi dual con textual facto rs. The durati on of il l -health is v ery v ariable. Symptoms may l ast for hour s, da y s, weeks or months. Someti mes full recovery never occurs. Pers ons wit h ongoing sympt oms should i dea lly be follow ed -up an d review ed by ex perienced medical pro fessi onals. Our publi - cation ou tl ines ongoing management and investigation in detail. The ti me of p resentat ion of i ll ness followi ng a FE i s i mportant. Symptoms characteristi cally occ ur in one of s everal time frames being: In - fli ght Immediat ely po st -flight (within 1- 2 days) Late/subsequent (beyon d 2 days) It is i mportant that careful records are kept at t he ti me of exposur e to a FE as these will assist w ith ongoing medical management. In particular, these include : the physical aspect of the exposur e (type of aircraft, where if the aircraf t, s tage of flight, smel ls /od our s etc) a carefu l medical record of sy mptoms and si gns, oxygen use, any tr eatment given, histor y of flyi ng (log boo ks etc). 4 Emerging Areas A number o f matt ers germane to the subject of FEs and Aerotoxic Sy ndro me have come to t he authors’ attenti on dur- ing t he ongoing devel opment of our manu script. These incl ude t he recognition that fine pa rticl es affect heal th and that u lt raf ine (nanopar ticl es ) are now accepted a s being more toxic. Experience has shown that l o w l evel fume expo- sures are al most ce rtainl y occurring on a r egul ar basi s and that they al most certai nly have a cumul ati ve effect. These observations under score the ne ed to improve air qual ity stand ards in aircr aft. 5 Medical Protocol Since our l ast presentation of this manuscript i n 2019 a s ig nificant amount of addi tional material has been ad ded. These include add it ional material and expan si ons of the foll owing sect io ns: Investigati ng Health and Exposure Circumstances of Per sons after Ai rcraf t Fume E vents 4 • Neur ology and neurotoxi city • Best collection times for anticholines terases • Eff ect of anticholines terases on differ ent ner vous systems • Eff ect of recurrent and cumulativ e low dose exposur e • Eff ect of ultrafine (nanoparticl es) particles • Ass ociation with fa t ig ue , sleep disorders, infection, malignancy, visual di sturbanc e, arthritic symptoms • Other p ossibl e associat ed co nditions eg malignancy, chemical sensitivity 6 Summary In summary, the medi ca l pr otoco l is now completed and i n t he edit ing phase . The auth or s accept that it has been a long journey but have w is hed to make the w ork the most c omprehensi ve to date. It i s a con sen sus do cument pr e- pared by i nternationally recognis ed ex perts in t he ir fiel ds. A pocket size booklet is a ls o being prepared fo r easy po rt a- bility and refer ence at the time of a FE. List of R eferen ces WIND ER, C. Balouet J-C. 2000 . Aerotoxic Sydro me : Adverse Health Effect s F ollowing E xposure T o Jet Oil M ist Dur ing Co mmercial Flights. In: Ed di ngton I (ed) Towards a safe and Civil Society. Proceedings of the International Congress on O ccupational Healt h Conference. 4 - 6 September, 20 00. Brisbane. MICHAELIS, S ., BURD ON, J. and HOWARD, C.V., 2017 . Aero toxic Syndrome : A new occupational di seas e  ? . Public Heal Panor. vol. 3, pp 198 – 21 1. In v es tig a ting Health a nd Exposur e Cir cums t ances of P er sons aft er Air cr a ft Fume E v ents : A Narr a ti v e R evi ew with Medic al Pr ot oc ol Jona tha n Bur don, L y gia T her ese Budnik , A strid Heut el beck, Xa v er Ba ur , Jor di R oig, Leonie Co x on, John Mi da v aine, Hannes P e ter se n, Ge r ar d Hag eman, Colin L . Sosk olne , Da vid Ge e, Clement Furlong , T rist a n Lor a ine , C. V y vy an Howar d , Susan M ichaeli s In t ernationa l Air cr a ft Cabin A ir Conf er ence, London 15 -18 Mar ch 2021 Backgr ound and Ov er vi e w • T erm ‘ Aer ot o xic S yndr ome’ - Not accept ed b y some • Aer ospace indus try does not lik e t erm • Not all pr esen t with same s ympt oms • ‘ Air cr aft r ela t ed illness ’ sug g es t ed (CAS A EP AA Q 20 12) • F or no w t erm ‘ Aer ot o xic S yndr ome’ r easonable & jus tifiable Backgr ound - Guidel ine s • Some pas t Guideli nes – none compr ehensiv e • Ackno wle dg ed tha t Guidel ines will v ar y • Our Compr ehensiv e Guidelines • Consen sus view of in t ernational e xperts • About 32,000 w or ds • V ery near c ompleti on • Upda t ed s ynop sis pr es ent ed t oda y • P ock et Gui delines wil l also be publi shed se par a t ely Sc ope of Pr ese n t a tion • W e ar e addr essing • Bleed/ su pply air con t aminan ts • Oils, h y dr aulic, de-icing fluids • Not other pollut an ts • P es ticides • In f ections T echnic al Ma t t er s (1) • Med ic al need f or un ders t an ding backgr ou nd of FE • Outsid e air used t o flush c abin & assis t with pr essurisation • Pyr oly sed oil in bleed air - not Boeing 787 Dr eamliner • Good da t a assis ts in med ic al in v es tig a tion/manag emen t • Air e x chang e r at es > than other ind oor sit es (sealed buildings) • High occupancy in air cr aft c abin T echnic al Ma t t er s (2) • Indus tr y se t s t and ar ds PR O TE C T MOST - NO T EVER Y ONE ! and ar e • No fine lines separ a ting health y fr om unhe alth y • Not a v aila ble f or all subs t ances • Set f or gr ound le v el • Not applic able t o c abin e n vir onment • T ak e no acc oun t of altitude / py r oly sed mix tur es Time of Pr ese n t a tion / Injur y • Time of pr esent ation with illness a ft er FE import an t • In -Fligh t • Immed ia t e P os t Fli ght • Lat e / Subseq uent • Mos t report s ymp t oms in-flight or immedia t ely a ft er • Long -t erm cumu la tiv e low dos e e xp osur e (months / y ear s) imp ort ant Pr ese n ting S ympt oms • Pr es enting s ymp t oms - descr ibed elsewher e • Ma y in v olv e al l or g an s ys t ems • Dur ation • Hour s, da y s, w eeks, mon ths • Sometimes , full r eco v er y nev er occur s S ymp t oms Experi enced a ft er FE - Summary ______________________ Neur oto xic Neur op s y chol og ica l R espi r a t ory Gas tr oint estinal Car dio v ascular Mucosa l irrita tion Other s En vir onmen t al In v es tig a tion of Fume E v en t: In -Fligh t R ec or d • T ype of air cr a ft • When did e v en t occur (s t ag e of fligh t)? • Wher e in the air cr a ft? • Wha t happe ne d (sme ll, fume s, smok e)? • Ho w long did t he e v ent c on ti nu e? • Describe ty pe of smell • Who and how man y (x out of y) a f f ect ed ? • R ec or d air quality monit or r ec or ding s (if a v aila ble) Medic al In v es tig a tion of Fu me E v en t: In -Fli ght • De t ailed car e ful his t or y of FE incl uding se v erity • R ecor d • Pr evious FE e xposur e and fr equency , leng th of ser vic e • S ymp t oms and pr ogr ession of s ymp t oms • Ob ser v ations of other s • Unu sual beha viour • Pr e-e xisting medical conditions • Oxy g en use (when /dur a tio n) including flo w r at e • An y tr ea tment giv en/used • T r ained medical pe r sonnel ma y r ecor d mor e Me dic al In v es tig a tion of FE: P os t Fligh t • Medic al, occ upa ti onal and FE e v ent his tory as be f or e • Wi l l be mor e det ail ed – healthc ar e w ork er s in volv ed ! • Hi s t ory of c ar eer flyi ng time (i mport ant) • De t ailed cli nic al e x amination • All or g an s y s tems • Emph asis on pr esenting complain ts, neur o logical and r espir a t ory s ys t ems • Men t al and cognitiv e s t a te impo rt an t • Special in ves tig ati ons - appr opria t e f or pr esenting c omplaints Medic al In v es tig a tion of FE: P os t Fligh t • Special In ves tig a tio ns - ap pr opriat e f or pr esenting c omp lain ts • Collect blood as soon as p ossible (r ecor d time fr om e xp osu r e) • Choline s t er ases* (ideal 4 -24 hr s) – *low e xp osu r e ma y not c ause inhibition • R outine biochemis tr y , haemat ology , muscle enzy mes • Other s, as cl inicall y ind ic a t ed • Carbo xyh aemoglobin - HbCO (within 2 hr s post fligh t, maximum 4 hr s) • Methaemoglob in • Collection time sh ould b e r ecor d ed and time from e xp osu r e. Medic al In v es tig a tion of FE: Ong oing Biomonit oring • After imme dia te pos t fligh t assessme n t • In ves tig ations based on clinic al indic a t ion • R epea t ag ain a t week 1, 4, 12 week s (especially cholines ter ase) or s ymp tom st ability • Note need f or r epea t cholinest er ase measur ements (2 -3 months) • Ma y allow f or normal assessme n t - Pr e- e xposur e le vels measur ements unlik ely . • Ong oing biomo nitoring allow s to xicological assessment r elative t o s ympt oms Medic al In v es tig a tion of FE: Ong oing In v es tig a tions • In ves tig a tions base d on cli nical indic a tion • In particular • Neur onal and glial aut oan tibodies – indica te neur onal injur y a nd gliosis • Det ailed lung function t es ting ma y be needed t o det ect r espir a tory injur y • Neur ologic al def ects – MRI sc ans, MRI/PET sc ans mor e sensitive • Neur obeha viour al – T ests include Coding t est (Pr ocessing speed), Pr oblem solving, Learning, Memor y , Sleep studies and other s • Malignancy – Emer ging r eports of some cancer s Medic al In v es tig a tion of FE: Eme r ging Ar ea s • R ecognised that fine part iculat es af f ect healt h • Ultr afine (nanoparticl es) no w ac cept ed as mor e t o xic • Lo w lev el r ecurr ent e xpo sur es pr obably cumulativ e in ef f ect • Under scor es iss ue o f ai r quality s t anda r ds Me dic al Pr ot oc ol – Additional Ma t eri al • Sections e xpand ed and further e x amined • Neur olog y and neur ot o xici ty • Bes t collec tion times f or an tic holinest er ases • E ff ect of a n ticholinest er ases on dif f er ent ner vous s y s t ems • E ff ect of r ecurr ent a nd cumul a tive low dose e xposur e • E ff ect of ultr a fi ne (na noparticles) particles • Associa tion with f a tigue, sl eep disor der s, inf ection, ma lignancy , visual disturba nce, arthritic s ymp t oms • Other possible associa ted c onditions eg ma lignancy , chemical sens itivity Conclusi ons • Pr epar ati on of medic al pr ot oc ol publi c ati on • Long journe y by man y • Some pr evious Guidelines and Pr ot oc ols • None as c ompr ehe nsiv e as pr esent • Consensus documen t - Int ernati onally e xpert author s • Bookle t also pr epar ed f or Guidance (Wha t t o do) f or air cr e w • Be pa tien t – we ar e almos t ther e ! Aircraft Cabin Air Intern ational Conference 2021 (ACA 2021) – Proceedin gs Confer ence: Online , 15-18 March 2021 Confer ence D irector: Trist an Lor aine Publishe r: London, UK: G CAQE (ht tps://gcaqe.or g) Editor s: Diet er Scholz , Susan Mic haelis How to cite this pap er (ISO 6 90, Harvard) : CABLE , Tony, 20 21 . An Air Accide nt Investi gator's Perspecti ve . Aircraft Cabin Air In ternation al Conference 2021 (Onli ne, 15-18 March 2021) . Lo ndon, UK: GC AQE. Av ailabl e fr om: https://doi.org/10.5281/z enodo .5211948 Review proces s: Edito rial r eview. The co rresp onding autho r is mark ed with *. 1 An Air Accide nt Investiga tor's Pers pective CABLE , Tony 1* 1 Accident a nd Failur e Techn ical Analysis Lt d (AFTA), Camber ley, UK E-Mail : tony .cable @zen.co.uk Copyri ght © 20 21 by autho r This work is licensed under the Creative Commons Attri butio n 4.0 Inter national Li cens e ( CC BY ). https://cr eati vecommons. org /licenses / by /4.0 Abstract While most investigations fin d ev idence suggesting why mistake s happened, in s ome cases it seems impossible to envisage why flig ht c rew made the m is takes th at they did. Two accidents ar e briefly de scribed. In each o f th e cases it is difficult to envi s age how th e exp erienced cr ew could have made th e catastrop hic err ors that th e y d id, unless they were impaired in so me way. It appears possible that th is could have been th e result of ingesting oil p roducts . Keywords cabin air, fume s , contaminati on, oil , mental capacity , error, aircraft, crash, a cci dent 1 Introduction Multiple cases with piston -engine aircraft wher e carbon monoxide poisoning cau s ed pilot impairment an d/or inc a- pacitation have occurred. Ad ditionally, th e re is an appreci able in cidence o f airliners suffering con tamination of cabin air with fumes, oft e n apparently due to oil entering th e air bled from engines or APU ( Auxiliary Power Unit) for cabi n pressurisation and conditioning. It appears that syn thetic oils , conta ining organoph os phate compoun ds , are widely used in engine s and APUs. In some of th e fum e event s flight crews hav e reported experiencing severe degradation i n their mental capacity and performance, an d only becoming aware of this a fter s tarting to use oxygen masks. It appears th at toxicological asses s ments at post morte m during accident investigations do not often includ e looking for signs of oil product in gestion. This raise s th e qu e stion as to wh e ther cabin air con tamination with oil prod ucts might insidiously h av e seriou s ly impaired th e crew, and con se quently h av e been a sig nificant causal factor in some apparently inexplicable accidents. Perha ps accident in v estigators have generally paid insufficient attention to th is possibility? 2 Boeing 72 7, Flight D A1008, 25 April 19 80, Tenerife, Can ary Island s, Spain A possible exampl e: Boeing 727, Flight DA100 8 – crash during a landing attempt at Tenerife Norte Airport in 1980 . ( Spanish Civil A v iation Accide nt Commission 1981 ). An Air Accident Investi gator's Per spective 2 The flight crew con sisted of two pilots and a Flight Engine er. The Commander had an a ppreciable amoun t of flight experience. He h ad flown to Tener ife N orte 58 times, and th e Co -Pilot 9 times. It i s in escapable that the crew knew that there was serious high groun d ar ound th e airport, with th e 12,188 ft Mt Teide only a relatively short distance away. DA1008 descended towards the airport, navigating using radio beacons, probably mostly in clou d, intending to conduct a procedural app roach based on an NDB (Non - Directional Beacon , a type of ra dio beacon). De viation s in ai r- speed, flight pat h, and position reporting, suggested cre w perfor mance may hav e been degraded. The Air Traf fic Con troller (ATC) made a n umber of serious errors, including clearin g DA1 008 to descend to a d ange r- ously low altitud e, an d unexpectedly i nstructing it to enter a h olding pattern b ased o n an NDB, using con tradictory and con fusing terms. The hol d was unp ublished, and therefore not on th e crew’s charts. None of th e crew m embers knew h ow to enter the hold. They discus sed the matter for over 2 minu tes, plainly showing they kn ew that they d id not know, while wanderi ng roun d to h igh groun d. DA1008 was at 6,000 ft altitud e, while in a sector with a minim um safe altitud e of 14,500 ft. The Ground Pro ximity Warning System ( GPWS) activated. The cre w a pplied full thrust, bu t did not level the wings, as specified by the p rocedure for a GPWS warning, an d this seriou sly d egraded the climb performanc e. The aircraft impacted the moun tains, killin g all on boar d. 3 Boeing 75 7, Flight A A965, 20 December 1995, Valle del Ca uca, Colom bia A further possible exa mple: A Boeing 75 7, Flight AA965, which crashed during a night landing approach to Cali, C o- lumbia in 1995. ( Aeronautica Civil of The Repu blic of Colo mb ia 1996 , Ladkin 1996 ). The pilots w ere q ualified an d h ighly experienced and must have known of th e mount ainou s terrain around Cali. Their inadvertent s election of an incorrect radio beacon caused a major d eparture of th e aircra ft from th e intend ed flight pat h alon g a valley lead ing to the airport. On realising this, while kn owing that they were unc ertain ab out their position, th e crew headed directly b ack towards the inten ded flight path. They did n ot seek assistance from A TC. On ap proaching h igh ground, a GPWS warn ing triggered. The cre w executed th e escape manoeu vr e, but o mitted to retract airbrakes, severely d egrading climb performanc e. T he aircraft i mpacted the mou ntain s, killing a n umber of the occupants. 4 Summary In each of th e ab ove case s it is dif ficult to envisage how th e experienc ed crew could ha ve made th e catastrop hic e r- rors th at they did, u nless th ey were impair ed in so me way . It ap pears p ossible th at thi s could have be en th e re sult o f ingesting oil prod ucts. List of References AERONAU TICA CIVI L OF THE REPUBL IC OF COLOMBIA, 1996 . Aircraft Acciden t Report: Cont rolled F lig ht into T errain. A merican Airlines Flight 965. Boein g 757-223, N651 AA . Near Ca li, Col ombia . December 20, 1995 . Sant afe de Bogot a, D.C., Colombia: Aer onauti ca Civil . Available v ia : LADKIN, Peter, 1996 . AA965 Cali Accid ent Report: Near Buga, Colombia , Dec 20, 1995 . Bielefeld, Ge rmany: Universitä t Bielefe ld. Available from: https ://bit.ly/2TNhR Al [viewed 2021-07-10]. SPANISH CIVIL AVIA TION ACCIDENT COMMISSION , 1981. Report on the acciden t to Boeing 727 G -BDAN on Tenerife, Canary Island s, on 25 April 1980. London, UK : Her M ajesty ’s Stationer y Office . Avai lable from: htt ps://bit.l y/2T4iODW [viewed 2021-07-10 ]. About the Author Tony Cable rec eived his degr ee in a eronautical engineer ing from the Un iversity of Lon don , United Kingd om. He work ed for Bo eing and Bri tish Aerospac e for a total o f 9 years. As an Air craft Accident In vestigation Consulta nt, h e s erved 32 years with th e Air Accidents In vestigation Br anch (AAIB), investigatin g th e engine ering a spects of acc i- dents an d incidents to many ty pes of fixed wing and rotary -wing aircraft with the aim of improving flight safety. These Aircraft Cabin Air Inte rnational Con ferenc e 2021 3 include th e crashes of Pan Am Flight 103 Bo eing 747 at Lo ckerbie, the RAF Chinoo k on the Mull of Kintyre, an d th e Air France Con corde at Pari s. H e has been a Consultant o n E ngin eering Failures for Accident an d Failure Technical An alysis Ltd (AFTA) for aroun d 15 years, chiefly in relation to majo r pub lic transport accidents. He is a n Aircraft Accident Inve s- tigation Lecturer and Visiting Fello w at C ranfield Univ ersity and a l icensed fixed- wing and h elicopter pilot. Aircraft Cabin Air Inte rn ational C onfe rence 20 21 (ACA 2021) – Pro ceedings Conference : Online, 1 5 - 18 March 20 21 Conference Di rector: Tristan Loraine Publisher: Lon don, UK: GCAQE (https://gcaq e.org) Editors: Dieter S cholz , Susan Michaelis How to ci te this paper (ISO 690, Harvard): MA JOR, Kris , COATES, Eoi n, 20 2 1. ITF/E TF P erspective of C ontaminat ed A ir . A ircr aft Cabin A ir Inter national C onfer ence 2021 (Onlin e, 1 5 - 18 March 2021) . Lond on, UK: GCAQE. A vailable from: http s :// doi.org/ 10.5281/ zenodo.555 849 0 Revie w proc ess: Editorial review . The corresp onding author is m arked with *. 1 ITF /ETF Perspective of C ontami na te d Air MAJOR, K ri s * , COAT ES, Eoin European T ransport W orkers' Federa tion (ET F) E- Mail : kris. major@ hotmail.co. uk , e.coates@etf - europe. org Copyrig ht © 20 21 by author ( s) This w ork is licensed unde r the Crea tive Com mons Attribution 4.0 Internation al License ( CC BY ). http s :// creativ ecomm ons . org / licenses / by /4.0 Ab str ac t Essential ly the poi nt of this paper is t o exp ress wher e th e Eu ropean T ransport Workers’ Fe deration (ETF) and t he In- ternational T ransport Workers' Fe deration (IT F) are and why we are suppor ting the cam paign f or cle an airc raft ca bin ai r. Keywords oil fu mes, fum e even t, ga s, d isea se, risk , organophosphates , ai rcrew, ca bin, a ir, flight s afety , aviation , i ndustry 1 Coal Mines U sed Can aries – Aircrew : Are They the C anaries of Today? Can aries were o nc e us ed in mi nes t o d etect od ourl ess ga s a nd b eing so s mall and l ittle and frail they would die lon g befor e the l ev el of ga s bec ame a n is su e for t he min ers 1 ( Smi thso nian Ma gazine 2016 ). " Seals " is a play on words . Of cours e, it o nly works in En glis h . I did c heck and f ind that in Spani sh the wor d for a (mechan ical) " sea l " is not the same as the S panish word f or " seal " t hat live i n th e sea and flap s it s fli pper s. A s eal a s we also k now is a mechanical pi ece of equipment th at restri cts gases and liqu ids from mov in g thr ough d ifferen t pa rts of an engin e or p iece of mechan ical engin eering. The m etapho rical refer ence to canaries an d their cre w just leads on to the w ord seal a nd why not jux tapositi on the wo rd betw een a m echani cal sea l and a living crea ture. Ev idence is co mpelling th e eviden ce is stro ng we have p eople that work on aero planes becoming sick . S t udies such as the Har vard proje ct indic ate that airc rew have a much incre ased risk o f deve loping certain c onditions and disease s than the g ener al populati on ( McNeely 2018 , H arvard T.H. Chan 2018 ) . Some of these conditions are also conditions that are linke d to exposure to organophosp hates and other c hemi cals found i n oil ope rating at hig h tempe rature s. 1 See also: BEAUM ONT, Bearnardine, 2 019 . Tomb in the Sky – Avi ation’ s Wounde d Ca narie s . Lond on, UK: Bowker. Availa ble from: https://www.amazon .com/dp/09 93302548 LA FAY ETTE , P orter, 201 7. Canary in t he Cabin . Availa ble fr om: https://a viationtravelw riter.com /201 7/04/02 /canary - in - the - cabin/ ITF/ETF P erspective of C ontami nated A ir 2 Now we a re no t sc ienti sts or engin eers or do ctor s th is c onference h as many of th os e offerin g in - depth detai le d chem- istry , b iolo gy and p hysi cs. I am su re th ey will offer co mpel li ng evi denc e tha t will o nce a gain reaffirm t he ab so lute n eed to d ig deep er r esea rch , mor e redo ubl e our ef for ts a nd n ot l et Cov id b eco me a convenient blanke t wi th whi ch to co ver this issue. Not only are we aircr ew , bu t we repr es ent t he air cre w. For us thi s is a really simp le ser ies o f ques tio ns , do es oi l at very hi gh te mperatur e get in to cabin ai r throug h the bl eed system? Does the oil that comes in to the cabin a ir sys tem have a w arning on the tin that says inhali ng this pr oduc t whe n used at high te mpe ratures c an le ad to de ath? Are we seeing peop le with illnes ses link ed to those ch emicals? Are we seeing people d ie with co ndition s linked to those wa rn- ings? 2 An Artifi cia l Envir on ment Other than a fe w w arning signs abo ut ke epi ng yo ur seat b e lt f astene d, not to smo ke, tu rn yo ur pho ne off and the od d sou nd of bells ringing t here is very little an d delibera tely s o to tell y ou exactly what airc r aft is do ing to keep y ou aliv e ( Fig ure 1 ). The truth is , we are in a c om ple tel y artif ic ial m anufac tured e nvironm ent de signe d to k ee p a human be ing alive and make t hem feel co mfo rtab le ( Fi gu re 2 ) . Even the l owest of t he lo w cos t ou tfits do n't med dle wit h that. But w e must unde rstand the exte nt to whi ch the environment t hat we are worki ng in i s lethal to us . O nly then c an we ima gine t he co mp lexity of the ma chin ery t hat makes the en vir onmen t on e we can s ur viv e in. Furthermore , we must also u nder stand that mo st air lines operat e the s ame ai rcra ft. Th e i ndu st ry is sava ge, co mpe- tition is fierce , an d margins are slim . T h erefo re , the rules and r eg ulations that w e f lyby have to be not j ust m ini mum standard s wit h no mar gin f or the odd fai lure or sli p. As we h av e alr e ady hear d , ther e ar e two d ist inct iss ues . O ne issue is the fai lure of a mec hanical part and a f ume even t of a vary ing degree. Th e oth er issue is being e xposed t o low - dose bur nt eng ine o il eve ry sing le da y , the cum ula- tiv e effect s of t hat over many year s. Th e lo w - do se cu mula ti ve eff ect is what conce rns us so de eply. Fi gure 1: Air trav el as we exp eri ence it . Ai rcraf t Cabi n Ai r Inte rnati onal Confere nce 20 21 3 Fi gure 2: Air trav el as it is . 3 Dange rous Chem ica l s Alrea dy the s cien ce o f thi s campaign has taken us on a jou rney , and it ha s led t o n ew revel ati on ( Fi gure 3 ). W e ha ve foun d t ha t th ere a re cert ain peo ple wi th c er tai n DN A th at will rea c t wor se t han mos t . W e wi ll find mor e ev iden ce t hat proves or g oes beyo nd re asona ble doubt – reasonab le medical dou bt – that the c hemica ls th at airc rew ar e brea th ing in , day after day , after day are af fe cting t heir heal th. Fi gure 3 Only a selectio n o f prese ntations del iver ed by scientist s at t he Ai rcra ft C abin Air Inter national Conf ere nce . ITF/ETF P erspective of C ontami nated A ir 4 We have so many yo ung wo me n work ing in this industr y at the poi nt of w hic h they are m ost li kel y to have c hildr en and they be ing e xpose d to these g ases. No , I don't know whether or not it is because I wor k in an industr y with l ots of wome n that we hea r of so m any ha ving i ssue s and pr oble m s wit h preg nancy f rom miscarr iage s, still births, ina bilit y to get preg nant and e ven losi ng babie s ? Or there is a problem that t his ind ustry is creating? Depr ess ion an d men tal illn ess is com monp lace in th is ind ust ry. No w I know th at we are a s a s ociety b ecoming more awar e of menta l ill nes s , h owe ver , I am still s eeing increas ing nu mbers of p eople tha t need mental clin ical help. This is the 21st - ce ntury w e do not nee d to ri sk othe r h uman be ing ' s healt h. Commercia l av iatio n is a relativ ely new business ; ther efore w e are o nly jus t seein g th e lon g - t erm effect s o f bein g in th is i ndu s try ( Fig ure 4 ). W e are onl y just hav in g peo ple h ave a 4 0 year career . W e'r e onl y ju st s ee ing peo ple i n ret iremen t dev elo pin g illn ess es in great er nu m- bers. W e have known t hat th e c hemic als that w e ar e using are dange rous . T he only que stion is b y how much c an we be exp os ed, reall y? Fi gure 4: Lon g term e ffe cts of ch emi cal exp os ure. Are we look ing at th is p roperly ? We know the che micals whe n inhale d are dange rous . T he onl y question i s how m uch. And are ther e al terna tive s to not brea thing i n the se c hem icals ? Yes , there are . Histo ry wi ll judg e the peo ple tha t think they a re v ery clev er , very big , v ery wise , and the ones wi th all the excuses to say " no , we mus t car ry on th ere is n oth - ing t o s ee here ". We ha ve s ys tems th at p reven t h uma n b eings fro m b eing ex p osed to thes e ch emic als . T here is no real reason on this planet to prev en t applying th ese system s. W hat we s us pec t is that it is about la wyers , abou t litigati on an d cos t which prev ent s t hes e sy stems t o b e us ed. 4 Delay s A gain and A gain Loo k we a ll k no w tha t t her e a re co mp an ies d esi gnin g s en so rs a nd filt ers . W e know that t hey c an be r et rofit ted . W e know that they wi ll work. Is it be yond re ason th at w hat is ac tually hap pening he re is dela y , the ta ctics of d elay! T his is a n industry issue not just a n individual operator is sue , whilst indi vidual o pera tors are faced w ith this . T h ere isn't glo bal p roactiv e dire ct ion fr om the bodies as it should be . So, we will continue to see the industry do eve rything they can to pu sh a solution of the problem into the future. Ai rcraf t Cabi n Ai r Inte rnati onal Confere nce 20 21 5 As a pragmatist you woul d say: H ow ca n w e con fir m ther e i s a pro blem ? And: Do we have a solution ? This is a mu ltibil - lion d ollar ind ustry . C an we conceivably stop peop le flying , if there i s a problem and we do not have a solution? W ell , yes , we ju st hav e – look what has happe ned with Cov id . I fe el t hat industry an d re gulato rs are e mpl oying dra g anchor s to s low d own a solution . T he appl ication of s enso rs and fil ter s seem like an oppo rtuni ty t o make thi s a hi storica l i ssue only. The future is safe and w e can hand this over to sc ie ntists and l awyer s to t hrash this ou t for year s to come. An d wh ils t th at mig ht s eem prefer abl e p arti cula rly b ecau se fume even ts mi gh t be r are r a nd ther efore not as many pa ss engers will be a ffe cted – it doesn’t fully resolv e th e pro b- lem o f lo w do se, c ont i nual exposure . The crew again are Canarie s being expose d to fumes until the sci ence c an catc h up and be ac cept ed as dama gi ng to our health. Ev ery d ay we dela y, more ai rcraft roll off th e pro du ction l ine with bleed air s ystems . E ach air craft means 20 years o r more t o con tami nat e aircr ew ju st b eginn in g thei r career s. Cost aside , the re i s little re ason for doi ng anything other than cha nging t he cabin air we breat he by chang ing how it is provided onboard . 5 Conclus ion With t he ev iden ce we have seen over the y e ars , it is difficult to suggest we as E TF a nd t he IT F shouldn’t be s uppo rting this campaign for clean cabin air with ever yth ing we h av e. I ha v e been flyin g for over 22 y ears – I hear an awful lot of counter evidence based on a lack of scie nce , or in conclu - s ive d ata , or new resea rch insti gate d by industr y , or regulators ha ve n ot detec ted anythi ng we should w orry about. In 22 ye ars a nd my positio n t hat put s me in contac t w ith cre w al l over the w orld, I hav e not hear d a s ingle crew memb er t ell th at t hey have bee n involve d in any ma jor study aim ed at l ooking at their he alth re lati ng to this to pic from any sourc e othe r than by unio ns an d group s wor rie d about the e ff ect s of cabi n air qualit y. I am not s uggestin g that indu stry ha s not underta ke n serio us studie s, only t hat the data I have see n prese nted by the co ncer ned gr oups is far mo re co mpell in g an d co mpreh ens ive . List o f Referen ces HARVAR D T. H. CHAN , 201 8. U.S. Fl ight A ttendants at Ele vated Risk of Seve ral For ms of C ancer . Ava ilable fr o m: https://www. hsph.harvard.edu/news/press - releases/flig ht - attend ants - can cer - risk , Archived at: https:// bit.ly/3is 6rem . MCNEEL Y, E ileen , MO RDU KH OVIC H, I rin a , STAF FA, S teven et al. , 20 1 8. Cancer P revalence amon g Flight Attend ants Com pared to the General Popula tion . In: E nvironm ental He alth , v ol. 17 , n o. 49. June 201 8 . Ava ilable from : https ://doi.or g/10.1186/s12 940 - 018 - 039 6 -8 . SMIT HSONIAN MAG AZI NE, 201 6. The Story of the Real Canar y i n th e Coal M ine . Availa ble from: https ://www.smithsonianmag. com/smart - news/story - real - ca nary - coal - min e - 180961 570 , Archived at: https:// bit.ly/3m nj1Nf . Aircraft Cabin Air Intern ational Conference 2021 (ACA 2021) – Proceedin gs Confer ence: Online , 15-18 March 2021 Confer ence D irector: Trist an Lor aine Publishe r: London, UK: G CAQE (ht tps://gcaqe.or g) Editor s: Diet er Scholz , Susan Mic haelis How to cite this paper (ISO 690, H ar v ard): SURI , Kanwar, GAO , Michael , CONRAD, David, 20 21. Advanced Technolo gy Filtration For A Better Crew And Passenger Experie nce. Aircraft Cabin Air Interna tional Conf erence 2021 (Onlin e, 15-18 Mar ch 2021) . Lond on, UK: GCAQ E. Available from: https://do i.org/10.5281/z enodo.489 8883 Related Pre sentation : htt ps://doi.or g/10.528 1/zenodo .4730410 Review proces s: Edito rial r eview. The co rrespo nding author is marke d with *. 1 Advanced Tec hnology Filtra tion For A Bett er Crew And Passenger Experience SURI, Kanwar 1 * , GAO, Michael 2 , CONRAD , David 3 1 Senior VP En gineeri ng , PTI Techno logies Inc . , Oxnard , CA, US A 2 Directo r of Enginee ring , PTI Techn ologie s Inc., Oxnard, CA , USA 3 VP Business D evelo pment , PTI Tech nol ogies Inc ., Oxnard, CA, U SA E-Mail : ksur i@pti technolo gies.com , mgao @ptit echnol ogies.co m , dconrad@ptit echno logies.com Copyri ght © 20 21 by autho rs This work is licensed under the Creative Commons Attri butio n 4.0 Inter national Li cense ( CC BY ). https://cr eati vecommons. org /licenses / by /4.0 Abstract Cabin air on comme rcial aircraft today is typically supplied b y b le ed air s ystems from engines or APU’s or ram air. Thi s input air contain s contamination, which may in clude hydraulic fluids, engine oil s , pyroly s is products, multip le ty pes of volatile organ ic co mpou nds ( VOC’s), ozone an d p articulates. For th e safety an d well -b eing of crews and passengers , removal of th ese type of these conta minan ts as w ell a s o dors fro m bleed air an d/or r e -circulat ed air i s essential to improve cabin air qu ality. Thinking of air qu ality as a matter of safety, as opposed to sim ply comfort, has dramatically changed the way that airline s make d ecisions regarding th e produ cts and serv ices u sed t o attain clean air in the cabin of the aircraft. Thi s is even m ore importa nt today as we work to provide a safe cabin en vironment to remove bacteri a and viruses. Airlin es, OEM’s a nd the tra veling p ublic are ju st now starting to realize ho w important cabin air qualit y is to the aviation in dustry. PTI Technologies ha s been in vesting in advanc ed designs an d new techn ology to m eet thi s need, an d has been testing this aga inst existing industry stan dards. Our presentation will shar e the results of this work and h ow it can positively impact the commercial a viation ind ustry by providing quality cabi n air for a better crew an d passenger exp erience. Keywords PTI, PTI Technologi es, cab in ai r , bleed air, contaminat ion , VOC, p articulates, ozo ne , safet y, cabin, environment 1 Introduction The cabin air on commercial aircra ft today is typically supplied by two sources – 50% from recirculated air and 50% by bleed air taken fro m th e com pressor s ection o f the engine s or AP U’s. The on e exc eption to day is th e 787, which use s compressed ram air. The 50 % of th e cabin air th at comes from the bleed air conta ins cont amination, which may i n- clude hyd raulic fluids, engin e o ils, pyrolysis produ cts, multi ple typ es of volatile o rganic co mpounds an d particu lates, as well a s ozon e. For the health , safety an d w ell -being of cre ws an d pas sengers, r emoval of these ty pe of contam inants Advanced Tec hnology Filtrati on For A Better Cr ew And Passenger Exper ience 2 as well a s o dors from b leed a ir and /or re -circulat ed air i s e ssential to impro ve cab in air quality . Thinking of air q uality as a matter of flight safety an d health, as opposed to simpl y comfort, has d ramatically c han ged th e way that airlines make de cision s r egarding the products and services used to attain clean air in the cabin of the airc raft. This is e ven more importa nt tod ay as we work to provide a safe cab in environment to remove b acteria an d virus es. Airline s, OEM’s, regulators an d the tr avelin g p ublic ar e just n ow s tarting to real ize ho w import an t cabin air quality i s to the aviation indu stry. PTI fir st succ essfully ap plied cab in air filtration technology in 1989 on the B -2 program, an d this has continu ed in a number of o ther military and manne d space program s. Durin g th is ti me, PTI’s engineering team has in vested in the development of special filter media by collaboratin g with media comp ani es to meet o u r cu stomer’s challenging r e- quirements and specifications . These application s required cu stom IP adsorb ents to ca pture gases such a s:  Ammonia  Phenol  Indole  Skatole  Butyric acid  Methyl Mercaptan  Hydrogen Sulphide PTI’s de velopment of cabin air filters for mil itary program has required developm ent of special cu stom ad sorbent s to capture Chemical Wa r Agent s (CWA) to pro tect cabin air in clu ding:  VX gas  Soman gas  Mustard gas PTI’s integration o f ad vanced integrated HE PA technology with adsorb ents i mpregnated p roprietary media technology is used today to meet perfor mance re quirement s of military and ma nned space cab in air filtratio n applications. In addition , PTI’s newest CabinS afe® HEPA te chnology h as been in service since 20 12 with global airlines for the recirc u- lation air loop on a nu mber of Boeing and Airbu s commercial aircraft. For bleed air applications, PTI has designed, manufactured and sup ported APU bleed air re moving liquids and p articulates o n a number of engine ap plications for P&W, Hon eywell, Lockheed, R olls- Royce, Airbu s, Embraer a nd militar y cu stomers. Over th e la st few years b ased on cust omer inputs, P TI Tech nologies began in vesting in a dvanced filter d esigns an d new technology to meet cu stomer needs in pro viding a higher level of filtration for Fue l Tank Inerting Systems (F TIS) to extend the life of th e air separation modules. PTI engin eering t eam h as now developed patented integrated F TIS filtration designs, which offer improved p erformanc e in ca pturing aerosols (liquid an d particu lates), Volatile Organic Compounds (VOC’ s) an d oth e r con taminants as well a s p roviding ozo ne conv ersion. P TI has manufactur ed the se FTIS filter designs an d tested the m in -hou se and at ind ependent th ird party lab oratories to EN an d ISO stan dards an d the results, show significant promise for improved filtration performance as discus sed below. During this techno logy d e- velopment and test programs, PTI also began to understand th at this technology was directly ap plicable to th e cha l- lenge of filtering the bl eed air portion o f aircraft cabin a ir. This technical p aper w ill show PTI’s d esign ap proach and results of our work on this in tegrated filtration technology and how it can po sitively imp act the co mmercial aviation i ndustry b y providing quality cab in air for a safer an d more healthy environm ent in th e aircraft a s well a s a b etter crew and pas senger exp erience. This paper will al so focus on how cab in air filters affect the quality of cab in air and how air filters can b e used to limit crew and passenger exposure to aerosols, VOC’ s, contaminan ts an d ozone. It will al so cover filter efficiency and explain why PTI is rec o m mending certain levels of fi ltration to achieve optimum r esults. Aircraft Cabin Air In ternation al Conference 2021 3 2 Ba ckgroun d Aircraft cabin air q uality and safety has ne ver been under such a stro ng public focu s as it is today, du ring the COVID -19 pandemic, especially given stron g evidence that these viruses can spread as aerosols thro ugh the air. However, in reality, the subject of aircraft cabin air quality has been a topic of discussion in the ind ustry since the 1950’s when Boeing first recognized the need for filtration, but did not have the filtr at ion technology to answer the problem. Al t- hough we have evolved techn ology an d slowly brought HEPA filtration to com mercial airc raft today , it has only b een a partial answer. With in the ind ustry, there h ave been a n umber o f issues and incident s where cabi n air quality h as affected the health of crew, flight safety fro m the incapacita tion of crew, as well as negative effects on p assengers. In doing design o f filter s to a ddress cabin air quality , there are many facto rs to consider . Aerosols ar e so s mall that buoyan t forces overcome gra vity, allowing t hem to say suspended in the air for lon g peri ods, or they e vaporate before they h it the floor, leaving th e solid particulat e (“droplet nuclei”) free to float very lon g distances, causing what we often re fer to as “airborne” transmission. There is g rowing evidence that in addition to contact and droplet spr ead, the tran smission o f aerosol s is plau sible und er fa vorable conditions, particularly in r elatively confined settings with poor ventilation and long dur ation e xpo sure to high concentration s of aerosols. A s we a ddress viru ses, the virus may attach to smaller o r lar ger p articles ( solid or liquid), so a wi de range of particle sizes hav e to be considered fro m som e micrometers down to the nan oscale. P TI’s advanc ed fi lter technology was de ve loped t o remove aero sols and viru s carrying par ticles to impro ve cabin a ir quality. Bleed air is o utside air and in theory it should be fresh and clean. However as it pas ses throu gh the compressor se c- tion of the engines or APU, it becomes contaminated with aerosol droplets or vapors o f engin e oil, hydraulic fluids, other organ ic o r inorganic co mpound s, carb on dioxide or other b y -prod ucts of co mbustion as they enter th e ai rcraft. The recirculat ed portion of ca bin air is not fresh an d given the p otentially large numbers of p asse ng ers on an aircraft, there are h igh concentratio ns of particulat es. These p articulates includ e fiber s, dust, skin par ticles , b acteria (up to 30,000 bact erial organ isms p er minute p er pas senger cou ld be relea sed in to the cabin environment), a s w ell as odors in the air in side an aircraft. Bacteria th rive in high hu midity, an d viruses thrive in lo w humid ity - both conditions can b e found on commercial aircraft. All of these conta minants are all a p otential risk to crews an d passengers. If we think of cabin air quality as a matter of flight safety an d h ealth, as opposed to simply passe nger comfort, it dramatically changes the way th at con sumers mak e decisio ns regarding the p roducts an d services u sed to attain clean air. Using an air filter with a higher Minimum Effici ency Repo rting Value (MERV) rating th an what a system is designed for, can actually impair its p erformance. The smaller pores i n more h ighly rated air filters create resistance to air flow, can lower the sy stem's efficie ncy and put strain on the overall system. Cabin air con tamination comes in t wo different forms: 1. Solid particulates (dust, polle n, smoke particles, du st mites). HEPA filters are u sed to filter solid par ticulates out mechanically. 2. Gaseous air p ollutants (odors, smells, VOCs, cigarette smoke smell, kitch en oil smell, etc.). The job of re moving this falls on the acti vated adsorbent portion of an air filter. The co mbination of HE PA filt ers and activat ed adsorbent filters workin g in tan dem i s n eeded to solve th e complex problem of cabin a ir quality - they are the two most i mportan t air purifier filters. Odors, smells, and Volatile Organ ic Compounds (VOC’s) just pass through HEPA filt er media as they are gases - a mechanical barrier does not stop th em. Rather, a pro cess o f adsorptio n to an activat ed ad sorbent material stops them. During the ad sorption p rocess, the gas molecule s ad here to a so lid surface of ad sorbents. PTI filters techno logy addresses th is issue b y u sing advanced integrated HE PA t e chnology, which integrate s HEPA filters with adsorbent impregnated proprietary media technology . Advanced Tec hnology Filtrati on For A Better Cr ew And Passenger Exper ience 4 3 PTI Advance d Integr ated HEPA Tec hno logy PTI’s current in -servic e cabin air filters are High Efficiency Particulat e Air (HEPA) filters and are manu factured u sing recommended practic es as p ublished in E nvironmental Technologies, not ASHRAE. PTI advanced integrated HEPA technology filters im prove s air quality by adding new technology to reduce VOC’s, minimizing ad verse h ealth effects such as head aches, n ausea an d nose/throat irritation or discomfort. Ou r integrated HEPA technology filters also r educe severe od or incidents thereby reducing unschedu led mainten ance and repairs and keeping flight s on schedule. These filt ers were develop ed w ith exten sive work con duct ed b y PTI’s Engine ering team in partnership with media man u facturers an d OE M’s. T ests con ducted b y independent labs h ave shown that Cabin Safe® advanced integrated HE PA filters with ozon e catalytic converters can reduce VOC’s and ozone concentra tions in the cabin thus keeping a h ealthy cabin air q uality for the crew and p assengers. T hese filters are engin eered with a mult i- layer media enab ling to t rap t he dirt an d large par ticles b efore the air r eache s the final fil ters downstrea m, whi ch then remove the small er par ticles. This multi -filter syst em extend s the lif e of th e filt ers, leadi ng to ov erall cost saving s. P TI advanced integ rated HEPA t ech nology filters can perfor m better for same basis weight and pressure drop a s other filters in the market. 3.1 Performance Test Data For Integrated Filter Elem ents PTI ad vanced integrated HE PA technology filters were tested p er E N 4618. Figure 1 shows the aeroso l (liquids and particulates) e fficiency ver sus particle siz e. Figure 1 Aerosol efficiency versus parti cle diame ter. The filter element was th en t ested a gainst single challeng e gases per E N 4618. The first challenge gas was for mald e- hyde :  Air Flow Rate: 45.7 5 cfm (3.5 l bs/min)  Upstream Conc entration: 38 p pb  Temperature: 160 °F ( 71 °C) The results of thi s testing are show in Fi gure 2 . Aircraft Cabin Air In ternation al Conference 2021 5 Figure 2 Adsorption cu rve : Efficiency versus time. PTI’s integrat ed filter elemen t was also sub jected to ozon e testing to det ermine perfo rmance of the ne w catalytic converter te chnology b eing used. This test was to deter mine both efficiency o f the converter an d performan ce at various temperature s. The test was performed at:  Air Flow Rate: 58.8 cfm (4.5 lbs/min )  Upstream Conc entration: 9.5 ppm  Temperature: 160 °F ( 71 °C) The results of thes e tests are sho wn in Fi gure 3 an d Figure 4 . Figure 3 Adsorption cu rve : Efficiency versus time. Advanced Tec hnology Filtrati on For A Better Cr ew And Passenger Exper ience 6 Figure 4 Efficiency versus te mperature . The filt er e lement was te sted against a mix o f five chall enge gases per E N 4618. The gas mixture wa s Butan e, Forma l- dehyde, N aphth alene, Toluene and Ozone. The te st condition s were:  Air Flow Rate: 45.7 5 cfm (3.5 l bs/min)  Upstream Conc entration: 13 p pm  Temperature: 72.3 °F ( 22.4 °C ) The test results are shown in Figure 5 . Figure 5 Adsorption cu rve: Efficiency v ersus time. 4 Conclusion s  PTI offers ad vanced HEPA filt er technology b est integrated solution for th e remo val of aerosol, air particu lates and VOC redu ction includ ing ozon e. Aircraft Cabin Air In ternation al Conference 2021 7  PTI’s Integrated Filter Mo dular Design 1. Used as a cabin air filter will eliminate adv erse h ealth effects for cr ew an d passengers, or if used in a FTIS a p- plication, in crease prote ction for the Air Separation Module (ASM) . 2. Provides low pre ssure drop . 3. Keeps energy co sts low and can be easily adapted for use in existing air s y stems. 4. Lightweight and long life. 5. Ensures econ omical operating costs . About the Authors Kanwar Suri h olds a MS (E ngineering) and DE R FAA c ertification for PTI Technologi es. He is th e Senior Vice Pr esident of Engineering with over 35 year s’ exp erience in hydraulic and filtration industry. He was a chairman of Vice Chairman of SAE Con tamination Committee and Secretary of NFPA Com mittee. He is acti vely involved in several SAE & NFPA tec h- nical committees and guides them to develop ind ustry standards, has writ ten an d presented technical pap ers to IN DA and FILTECH filtratio n conferen ces an d holds se ve ral US pat ents in the field of hyd raulic filtration and press ure s ensing devices. Michael Gao recei ved his B.E . and M.E. degre e in Mechanical Engineering from Zhe jian g University, Hangzhou , Pe o- ple’s Republic of China in 1989 and M.S. degree in En gineering Mathematic s from Claremont Grad uate University, Claremont, California in 1996. From 1996 to 2000, he was a De sign Engineer; Project E ngineer with Western Filter Corp. (now Donald son). Since 2001, he has b een a Sr. Des ign Engineer, Sr. Project E ngineer, Engineering Man ager and the cu rrent position of Direct or of E ngineering with PTI Te chnologies Inc. He i s a voting committee member of S AE A - 6C1 Contaminat ion & Filtrat ion Group, SAE AE -5D Fuel Tank Flammability Reduction Systems Grou p and has au thored numerous SAE docum ents for pub lications. Mr. Gao hold s f our US Patent s and is an exp ert in the a erospace filtration industry. David Conrad recei ved the B.S. degree in Chemical an d Petro leum R efining Engine ering from th e Colorad o School of Mines, Golden, Colora do in 1979. Curr ently, he is the Vi ce Presid ent, Bu siness De ve lop ment at PTI Technologies based in Oxnard, California. Before joining PTI, h e was with Zodiac Water & Waste Aero Syst ems as Vice President, Sales Marketing and Customer Ser vice. H e sp ent three years a s the Director In ternational Sale s & Ma rketing of Guangzh ou Aircraft Maintenance and Engineering Co., Ltd (GAMECO ) in Guangzh ou, Peopl e's Rep ublic of China . He has also served as the Vice Pre sident, Sales, Marketing and Customer Service as well a s G eneral Man ager, PSI at Rexno rd Aer o- space, as well as p ositions with Goodrich Cargo Systems ( based in B eijing, China), an d AeroUnion Corpora tion. He began h is car eer p rogressing through a number of b usiness de velopment an d leadershi p positions in Honey well/ A l- liedSignal. Mr. Conra d holds o ne US Patent. ESCO Aerospace & De fense PTI Technologies Inc. Advanced T echnology Filtr ation f or a Better Crew a nd Passenger Experience Air cr a f t Cabin Air In t erna tional Con f er ence 2021 18 Mar ch 2021 Warning: Information Subject to Ex port Control Laws This document is co ntroll ed under jurisdictio n of Export Admin istration Regulations (EAR), 1 5 CFR parts 7 30 to 77 2. Diversion contr ary to U.S. law is prohibi ted David Conrad Company Private – © PTI Techno logies 2021 ESCO Aerospace & Defense PTI Technologies Inc. Situa tion And Nee d – Our Vie w  Air c r aft c abin air c omes fr om two sour ces • 50% - “Fr esh” Air (bleed air fr om eng ine / APU compr essor section) o Ex ception is 787 – r am air • 50% - R ecir culat ed A ir fr om cabin  The R ecir c ulat ed Air is tr ea t e d t oda y – H EP A Filter s • R emov es particulat es, viruses, bac t eria, fungu s • Does not h andle gas es/ odor s – need second media ( activ a ted carbon)  How ev er , “ Fr esh” Air r eal ly has no tr eatmen t e x cept O z o ne  The “ Fr esh” A ir co mponen t is the driv er of ai r qualit y • Cont ains aer osols, VOC ’ s, particula t es and o z one • Cr eat es h ealth/ saf e ty issues f or fligh t c r e w • Degr ades passenger e xperience • No filtr a tion/r emo v al and low o z one con v er sion a t low er t emper a tu r es 2 An E ff ectiv e S olution F or Blee d Air Fi ltr a tion Is Ne eded Company Private – © PTI Techno logies 2021 ESCO Aerospace & Defense PTI Technologies Inc. P ot en tial V OC ’ s In Engine Bl eed Air 3 Man y P o t en tial V OC ’ s In Bleed Air – Comple x Pr oblem T o R emove All Company Private – © PTI Techno logies 2021 ESCO Aerospace & Defense PTI Technologies Inc. Situa tion And Nee d – Our Vie w  Wha t ar e the challe ng es f o r e f f ectiv e solution f or Bl eed Air ? • Which V OC ’ s t o r emov e – which possible ones to choose? • How t o b es t r emov e aer osols (liquids, particulat es)? • How t o ge t b et t er oz one con v er sion - especially a t low temper atur es? • P ac k aging filte r f or air c r aft (f ootprint, w eigh t, certifica tion, lif e)? • How t o mak e inst alla tion eas y (new , e xis ting) ? • How t o mak e cos t ef f ectiv e t o ins t all, op er a t e and main t enance?  F ortunat ely , ther e is a solution • New t echnology f or b leed air in F uel T ank Inerting S y s t ems (F TIS) • Simple d esign, low er wei ght, long lif e, economical cos ts • Handles aer osols, VOC ’ s , an d o z one in a single en v elope • Combined with r ecir c filter s – b et te r cabin air qu ality  Filt er design tes t ed – r eady t o fit t o air cr aft, w orking with partner s 4 T echnology Now T es ted And In Hand F or Bleed Air S olution Company Private – © PTI Techno logies 2021 ESCO Aerospace & Defense PTI Technologies Inc. Wha t ’ s A t St ak e  Our industry – flight cr ews • Cont aminat ed air h as impair ed an d incapacita ted fligh t / cabin cr ew  Our industry – passenger s • Exposur e to chemicals, fumes an d oz one – public health risk  Our industry - ma nuf actur e r s • Idea of filtr a tion now ne w – consider ed since 1 950’ s bu t lack of solutions  Air Accide n t In v es ti g a to r s globally and Law Courts • Cont aminat ed air e xposure - ri sk t o fligh t saf ety , cre w and pub lic health • Under st anding of chemicals pr esen t during these e xposure e v ents • Incr eased financial and leg al liability • Call on re g ula tor s / Gov ernmen ts t o manda te ef f ectiv e “bleed air ” filte r s and cont amina t ed air w arning sensor s on passenger air cr aft 5 Call T o Action – Solutions Nee ded F or C r ew And P assenger s Company Private – © PTI Techno logies 2021 ESCO Aerospace & Defense PTI Technologies Inc. PTI’ s P edigr ee In Air F iltr a tion  Who is PTI T echnologies • W orld leader in a via tion/ aer ospace filtr ation f or o v er 6 0 year s • Filtr ation f or all air cr a ft fluids – h ydr aulics, air/bleed air , fuel, w at er , lube  Our e xperience and pe digr ee in air fil tr a tion • W e h a v e supp lied air filtr a tion f or milit ar y aircr aft sinc e the 198 0’ s o Special media developed to captur e danger ous gases/ chemicals/particul a t es • Continued de v elopment f or milit ary toda y – cabin air an d br ea thing air • Dev eloped / certified of air filtr ation f or Sp ace Launch Sy s tem (gas es) • Dev eloped / certified / in-ser vice HEP A Cab in Air Filt er s f or airl ines • Dev eloped / c ertified / in-service eng ine / APU bleed air filtr a tion • Dev eloped / t es ted filtr ation c ombined with cus tom absorben ts • Dev eloped / t es ted pat ent ed FTIS filtr a tion (Aer osols, VOC ’ s, HEP A, Oz one) 6 PTI Has P edigree And T echnology F or Bleed Air So lution Company Private – © PTI Techno logies 2019 ESCO Aerospace & Defense PTI Technologies Inc. Aer ospa c e Pr oduct Applic a tions 7 Flight Contr ol Fil tr a tion  Rudder Co ntrol  Elev ator s  Ailerons  Ground Spoilers  Thrust Re versers Main Hy d r aulic Sy st ems  Multi-component Manif olds  Pressure  R etur n  Case Dr ain  S yst e m Fill Auxiliar y Pow er Uni t  Fuel  Lube  Bleed Air Liquid Coo ling Sy st ems  A vionics  Radar  Galley Engine Filtr ation  Fuel  Main Lube  Sca veng e Lube  Bleed Ai r En vi r on men tal  Cabin Air  Electronic cooling  W ast e sy stem  P otable W ater Electric S ys t e ms  IDG Lube  CSD Sca veng e Company Private – © PTI Techno logies 2021 ESCO Aerospace & Defense PTI Technologies Inc. PTI’ s Solution T o Ble ed Air Filtr a tion  Solution – Adv ance d T echnology Fi ltr ation de v e loped f or FTIS • R emov es Aer osols (Liquids, P articula t es), Gases/V OC ’ s, Oz one + HE P A • Incorpor a t es multila yer media, activ e absorben t and oz one con v er sion • Pr ov en pat en t ed technology and designs  T es ted t o E N / ISO St andar ds • Aer osols ( Liquids, P articula t es) • Challenge Gases – sing le and mix ed • Oz one con v er sion 8 Company Private – © PTI Techno logies 2021 ESCO Aerospace & Defense PTI Technologies Inc. Bleed Air Filtr a tion T es ting – EN 4618-2009 9 Company Private – © PTI Techno logies 2021 ESCO Aerospace & Defense PTI Technologies Inc. T es ting R esults 10 GAS ADSORPTION AER OSOLS ( fine solid particle s / liqu id dr o plets) O Z ONE Company Private – © PTI Techno logies 2021 ESCO Aerospace & Defense PTI Technologies Inc. Wha t ’ s Ne xt  Ne x t s t ep is to bring blee d air fil tr ation in-ser vic e to airline s • Specifica tions (bleed air , filtr a tion) to optim iz e d esign / perf ormance • Pr ototypes / fligh t tes t pr ogr am • Certific ation – ST C an d / or OEM • R e tr ofits / ne w pr oduction  Need airl ine par tner s - collabor a t e on de sign/ins talla tion/t est  Need OEM suppo rt f or s imple solution • Certify acr oss p la tf orms • Cr ea t e aft ermark et support – docu men t a tion, manuals 11 T ec hnology Is In Hand T o Addr ess The Bleed Air Filtr a tion Ne ed Company Private – © PTI Techno logies 2021 ESCO Aerospace & Defense PTI Technologies Inc. F or Mor e In f orma tion / P a rtnering 12 C ONT A C T : Da vi d Conr ad , VP , Business Dev elopmen t dconr ad@p tit echnologie s.c om +1 (805) 604-3844 Aircraft Cabin Air International Confe rence 2021 (ACA 2021) – Proceedin gs Confer ence: Online , 15-18 March 2021 Confer ence D irector: Trist an Lorai ne Publishe r: London, UK: G CAQE (https ://gcaqe.or g) Editor s: Diet er Scholz, Susan Micha elis How to cite this paper (ISO 690, Harvar d): FURDAL DAMM , Gitte, 20 21. Patching up Risks? – A View on Human Factors and Toxic F umes . Aircraft Cabin Air Internat ional Conferen ce 2021 (Onli ne, 15-18 March 20 21) . Londo n, UK: GCAQE. Av ailabl e fro m: https://doi.org/10.5 281/zenodo.5515 475 . Related pres entation: ht tps://doi .org/10.5281/zeno do.551539 9 Review proces s: Editor ial r eview. 1 Patching up Risks? – A View on H uman Fac tors and To xic Fumes FURDAL DAMM, Gitte Human Fact ors Cons ultan t at "About Human Facto rs" E-Mail : info @abouthu manfacto rs.dk Copyri ght © 20 21 by autho r(s) This work is licensed under the Creative Commons Attribu tion 4.0 Internat ional Lic ense ( CC BY ). https://cr eativeco mmons. org /licenses/ by /4.0 Extended Abstract Historically a viation is kn own for improving an d enhancin g th e de sign of air craft, from the 19 80’s Ground Pro ximity Warning Syste m ( GPWS) un til to day's a dvanced automatio n with reduced separation allowing for more traf fic. So m e- times howe v er , the sy stem b ehaves in ways th at the d esigners d id not think o f – an example of th is i s the B737 MAX , or an oil leak af fecting the air quality and the people workin g onb oard an aircraft. Very often th e design is finished by the most ada ptive element in a system – the p eople, an d we may not even n otice that th e design was fla wed in th e first place. But what assumptions lie aro und risk, when we talk abou t to xic fumes in the aircraft? Di ane Vau ghan ( 1986 , p. 62) tells us that “Risk is in th e ey e of the beholder” an d it seem s that the risk associated with toxic fum es d epends on the eyes looking at it. From a regu latory p oint, th ere s eems to b e different views on the ri sk associated with toxi c fu mes. While ICAO ( 2015 , p. 1) states: “ … particu lar concerns hav e been raised r egarding the n egative impact on flight safety when cr ew member s ar e exposed to oil or hyd ra ulic fluid fu mes or smoke and experien ce acute sym p to ms in flight”, EASA 2017 seem s to come f r om a d ifferent perspectiv e: “ Contaminated air is not a flig ht safety issue. Th e air q uality on a p assenger jet aircraft is si milar or better than what is o bserved in n ormal indoor environments”. Yet, an increa se in repo rts of smell, smoke an d fumes have increased over the la st fiv e years ( AAIB 2020 ) an d from investigating numero us fume events, com mon featu res ha ve b een identifi ed. These co mmon feature s sugges t a sy s- temic d esign flaw not presen tly accounted for, an d for the p eople involved this emergent syste m property changes the risk profile. Humans ad apt to make th ings work. Mo st of the tim e things go well, b ecause h umans i n th e system are fan tastic, through their ab ility to adapt and adju st their per formance to pat ch up system s imper fections and messy d etails th at seems to go beyon d th e designs in th e system, in ultimately sustaining the daily o peration. But this ad apta bility is f i- nite ( Woods 20 15 ) and suscep tible to o uter factors in fluencing. H umans make an enor mou s contribution to safety, b ut certain de signs in work struct ures, equip ment and tools needs to be in plac e for th e sharp end peop le to do their jo b in a safety critical en vironmen t. Checklist serves to aid th e pilots a s simpli fied mean s in abn ormal situat ions, lik e a toxi c fume event. Toxic fum es are often no t asso ciated with sm oke b ut smell, and often ap pear suddenly with rapid effect on the crew. The design of Patching up R isks? – A V iew on Hum an Factor s and Toxic Fumes 2 some checklist in regard s to smok e/ fume s therefore seem s to be incomp lete a s these ar e “ geared towards identifi c a- tion an d isolation of an y p ossible sourc e of smoke in the a irplane. Ther efore it is not suited to determine an d eli m i- nate the various caus es of s mell” ( BFU 201 5 ). From AAI Bulletin ( AAIB 2000 ) an example of how the pilo ts patch up the deficiencies of the sy stem seems to rely on their previous experience. The report states that both pilots had been exp osed to toxic fumes before, which they had discussed the evening befo re. “ The flight crew’s previo us experience suggested th at if the smell was going to r e- occur, it was most likely to occur wh en thrust was reduced for descent, so during the cru ise th ey discu ssed their a c- tions if the smell retu rned an d reviewed the SMOKE/F U ME S/AVNCS C hecklist” ( AAI B 2020 , p. 2). On e may ask wh ether we can rely on sufficient exp erience being pres ent o n the fli ght deck to prevent harm ? An d whether this responsibil ity should be p laced in the h ands of the p ilots? What perhaps seem s to go unrecognized i s ho w peopl e are the most ad aptab le element in a complex work system, and what th is means to the wider syste m – like system s safety. “ People are th e most ad aptable element in any co m- plex work syste m. This ad aptability is essential in making th ings work, both in ordin ary b ut especially in extraordinar y circumstance s” ( Wear s 2013 , p. 338). Safety is not someth ing we ha ve, safety i s so mething we do, and d ependent upon the adap tive cap acity present. One may wonder, are we willing to trad e this ad ap tive cap acity and ignore the signals of risk from the sharp end p eople, research and investigation s, at the expense of safety and employe e's h ealth and well being? This text suggests that d esign impro vement i s required, in order not to jeopar dize the h ealth and well-b eing o f the employees. “ Users should n ot have to adap t to support systems, rather sy stems sh ould ad apt to supp ort users” ( Wears 2013 , p . 1). Keywords risk, human fact ors, fume even t, toxic fumes , flight saf ety , health , adapta bility List of References AAIB, 2020. A AIB Bul letin: 9/2020. G-EUYB. AAIB- 26125 . Availab le fr om: https://bit.l y/3lI54sW . BFU, 2015. B undest elle für Fl ugunfalluntr suchung. Inve stigati on Report B FU15 -006- PX . Availab le fr om: https ://www.bfu-web.de/EN/ Public ations /Investi gation%20Report /2015/Beric ht_15- 0006 -PX_A321_Ha mburg_ Smell.pdf EASA, 2017. C AQ – Preliminary Cabin Air Quality Measurement C ampaign. Cologne, Germany: European A viati on Safety Agency (EAS A). P rojec t partne rs: F raunhofer ITEM, H annover Medical School (MHH), Lufthansa Te chnik AG / D eutsche Lufthansa AG, Condor Flugdiens t GmbH, B ritish Airways. Avai lable from: htt ps://bit.ly/2U8ZpyF , Archive d at: ht tps://perma.cc/PW6Y-7S9U . ICAO, 201 5. Cir 344-AN/202: Guide lines on Educ ation, T raining and Report ing Practices rel ated t o Fume Eve nts. Mont réal, Qu ebec, Canada: Interna tional Civi l Aviatio n Organization ( ICAO). Available from: https ://bit.ly/3k Oi8v8 , Arc hived at: https ://perma.cc/PM X5-PPY7 . Vaughan, D., 1996 . The Chall enger. C hicago, USA. The Univer sity o f Chicago Press. Avail able f rom: https://www.amazo n.com/dp/B00 EKYGU2Y . Wears, R., Hettinger, Z., 2013. The Tragedy of Adaptabili ty. A nnals of Emergency Medicine , v ol . 63, no. 3, March 2014, pp. 338 -339. Availabl e from: https ://doi.org/10.1016/j.anne mer gmed.2013.10. 035 . Woods, D., 2015. Four Concept s for Resilienc e and the Implications for the Future of Resilience Engineeri ng. Re liabilit y Engineering and Syste m Safety , vol. 141, Septe mber 2015, pp. 5-9. Available f rom: htt ps://doi.or g/10.1016/j.ress .2015.03.018 . About the Author Gitte Fu rdal Da mm is a former captain on the A TR 72 - 600 and has been working at variou s Dani sh Airlin es such as Cimber Air an d Jettime. Sin ce 2015 she has be en a CRM Trainer and is the o wner of Abo ut Human Factors, whi ch pr ovides CRM courses in a viation . Sh e is curr ently also a ttend ing th e MSc p rogra m in Hu man Facto rs and System Safety at Lun d University. Page 186 could not be converted This page was skipped, but the rest of the document is available. Response ended prematurely Page 187 could not be converted This page was skipped, but the rest of the document is available. Response ended prematurely Page 188 could not be converted This page was skipped, but the rest of the document is available. Response ended prematurely Page 189 could not be converted This page was skipped, but the rest of the document is available. Response ended prematurely Page 190 could not be converted This page was skipped, but the rest of the document is available. Response ended prematurely Page 192 could not be converted This page was skipped, but the rest of the document is available. Response ended prematurely Page 193 could not be converted This page was skipped, but the rest of the document is available. Response ended prematurely Page 194 could not be converted This page was skipped, but the rest of the document is available. Response ended prematurely Page 195 could not be converted This page was skipped, but the rest of the document is available. Response ended prematurely Page 196 could not be converted This page was skipped, but the rest of the document is available. Response ended prematurely Page 197 could not be converted This page was skipped, but the rest of the document is available. Response ended prematurely Page 198 could not be converted This page was skipped, but the rest of the document is available. Response ended prematurely Page 199 could not be converted This page was skipped, but the rest of the document is available. Response ended prematurely Aircraft Cabin Air Intern ational Conference 2021 (ACA 2021) – Proceedin gs Confer ence: Online , 15-18 March 2021 Confer ence D irector: Trist an Lor aine Publishe r: London, UK: G CAQE (ht tps://gcaqe.or g) Editor s: Diet er Scholz , Susan Mic haelis How to cite this paper (ISO 690, Ha rvar d): DIAMOND , Marc us, 20 2 1. Cabin Air Quality Mo nitoring – Organophosphat es Sampling during Fume Events in Australia . Aircraft C a bin Air Interna tional Conference 2021 (Online, 15-18 March 2021) . London, UK: GCAQE. Availab le from: https://do i.org/10.5281/z enodo.556 7738 . Review proces s: Edito rial r eview. Related presentat ion: ht tps://doi .org/10.5281/ze nodo.5567722 . 1 Cabin Air Quality Mo nitoring – Orga nophos phates Sampling duri ng Fume Events in Australi a DIAMOND , Marcus Safety & Technical , Austr alian Federation of Air Pilots, M elbourne , Australia E-Mail : marcus@af ap.org .au , Copyri ght © 20 21 by autho r(s) This work is licensed under the Creative Commons Attri butio n 4.0 Inter national Li cens e ( CC BY ). https://cr eati vecommons. org /licenses / by /4.0 Extended Abstract Purpose: The Australian Federatio n of Air Pilot s (AFAP) pre s ent ed the re sults of organoph osphate analysis from cabin air sampling on VH -registered aircraft durin g pilot - reported fume e vents. A s part of a wider Global Cabin Air Re porting System (GCARS) study, AFAP pilot members undertook a small -scale initial trial of the new GC ARS reportin g tool. Traces o f th e neurotoxin T ri cresyl Phosphate ( T CP) had p re viously been found in air samples taken on b oard various aircraft in other studie s . Th e AFAP an d its pilot members have an ongoing interest in cabin air quality and better unde rstanding the extent and frequency of the incidence of TCP an d other organo phos phates in reportable fume events. Methodology: Cabin air samples were coll ected by pilots during a repo rtable fume event u sing a small p ersonal air monitor device – th e ‘VN sa mpler’ . This small air samplin g syst em em ploying standard air filter sa mpling technolog y was used to monitor cab in air in do mestic pas senger air craft flying domestically within Australia o ver the trial p eriod from July 20 18 to June 2019 . The device i s a small AB S con structed cylinder (5 cm d iameter x 9 cm height) that can b e readily op erated by pilots who were i nstruct ed to op en the sampler if they detect ed a reporta ble fume e vent and co l le ct a mbient cab in air for up to one hour. On ce acti vated, the sa mpler wa s in operat ion for the du ration o f the flight or for the li fe of the batteries (ap proxi mately 1 hour), whiche ver is shorte st. The VN samp lers were r eturned to a laborato ry where the standar d 37 mm filter s (onto which volatile compounds had adh ered) we re removed and any organop hosphates prese nt we re an alysed b y gas chromatograp hy -mass spectro metry (GC-MS). The only air sampler to be approved by the Federal Aviation Administration , the VN sampl er has previously been shown to be capab le of monitoring air concentratio ns of TCP isomers in aircra ft above 4.5 n g /m 3 ( van Netten 2009 ). Note: ng, nanogram , 10 − 9 g. Findings: A set o f 20 samples taken by pilots du ring Australian do mestic flights an d an alysed by G C- MS, s howed th e presence of o rganoph osphates in 16 (80%) samples . Sample s were ta ken on r easonab le suspicion of a fume event th at would be “ reportable” , u sually (but n ot always) resulting from a no table odou r (or s moke in more o bviou s incident s). Often the notable odou r was so mild as to be imperceptible to some crew members. For instance, sample 115 was collected when only o ne cr ew m ember dete cted a very mild s mell . This aircra ft had an other fume event six week s Cabin Air Qu ality Monitor ing – Organop hosphate s Sam pling during Fume Events in Aust ralia 2 later which engineers attribu te d to oil leaking from the auxiliary power unit ( APU) into its air in take. Analy sis o f this set o f samples ind icated expo sure to Tricresyl Phosph ate ( TCP) lev els ran ging from LOD to 3872 ng /m 3 (d et ection li mit < 4.5 ng /m 3 ). Of the total sa mples analy sed, 80 % conta ined significan t/high con centra tion s of Tricresyl Phosphate (TCP) and other organophosphates including T ri butyl Phosphate (T B P) . Given le vels of T BP and TCP in normal flights are usually close to or below our detection limit, all th e collected and analy sed sample s (except sa mple 83 ) id entified that th ese organophosphat es were present in signifi cant concentra tions. Research Limitations: Th is small-scale trial was only a study of a limited number of reporta ble fume events (n=20). To obtain a better in dication o f t he incidenc e of organoph osph ates during fume e vents, a la rger study wou ld be r equired. Elevated lev els of Tributy l Ph osphate ( TBP) have be en as sociated with the u se o f th e aux iliary power unit (APU) in th e aircraft. A larger -scale, contro lled experiment d esigned to ad just for other variable s such as this would b e required . Practical Implications: Tricres yl Phosphate (TCP) i s an indicator of bleed air con tamination of aircraft cabin air. It was noted th at a naly sis of sa mple 119 gav e one o f th e h igher r esults for TCP (and TBP) yet there was b arely a detectable odour during th e flight. The implications for further research are significant. This d ata appears to ind icate th e value o f continuou s real-time air qu ality monitoring in the cabin to reveal any fume events that may escape repo rting reliant on rudimentary d etection by air crew through a n oticeable odour o r smoke. Social Implications: The outcome s of this study have been pres ented to airline execu tives and others within the Aviation indu str y in attend ance at t he 2021 ACIAC. Value and Origina lity: Th is trial stud y is the first multi-scale collection of r eal-ti me cabin air sampled by pilo ts during (rather than following ) repo rtab le fume event s (and sub seq uently an alysed to collect TCP isomers an d TBP data ). Keywords cabin air sampling, personal air mon itor , organ ophosphates, air pollutan ts analysis, indoor air pollution , aircraft standards, air mon itoring, gas chromatograp hy, mass sp ectrometry List of References VAN NETTEN, C. , 2009. Desig n of a Small Personal Air Moni tor an d it s Applica tion in Aircraft . In: Scienc e of T he Total Environment , v ol . 40 7, no. 3, pp. 1206 - 1210 , 15 Januar y 2009 . Avail able from: htt ps://doi.or g/10.1016/j. scito tenv.2008.07.067 , Arc hived at: htt ps://perma.cc /HK88-TUVD . Acknowledgements The autho rs acknowl edge th e financial support and other resource s of the Au stralian Federation of Air Pilot s which made this work possible . The au thors grateful ly ackno wledge the contribu tions from Pro fessor Chri stiaan van N etten, Professor Emeritu s at the Sch ool of Population and Pub lic Health, Faculty of Medicin e, University of British Columbia, Vancouver, Canad a. The auth or d eclares th at no con flict of interes t exists with the results and con clusions pr esented in th is paper . Pub lication ethics h ave been observed . About the Author Marcus Diamon d rec eived the B.Sc. d egree f rom the University of Melbourne , Victoria, Australia (1986) an d later a Commercial Pilot L icence and an Air Transport Pi lot Lic ence (1 996). H e has worked a s a n airline cap tain in Australia, New Zealand and Papua New Guinea and is currently the Safety & Technical Manager at th e Australian Fe deration of Air Pilots in Melbourn e, Australia . Captain Diamond also serves on the AusALPA safety an d technical committ ee and has attended p as t Aircraft Ca bin Air con ferences. Cpt Marcus Diamond Cabin Air Quality Monitoring – Or g anophospha tes Samplin g during Fume E v en ts in Aus tr alia International Aircraft Cabin Air Conference 2021 Online, 15-18 March 2021 Do z ens of c oncerned and af f ected pilots Ther e ar e unansw er ed questions Unactioned findings fr om Go v ’t r evie w s & enquir y R efut able st at emen ts in other sampling s tudies Adding t o the da t a Our industry needs to ackno wledg e the problem and impr ov e WHY SAMPLE? // 2000 AUSTRALIAN SENA TE ENQUIR Y // The c ommit t ee r ecei ved consider able evidence cri tic izing aspects of the regula t ory r egime f or the air cr a ft and f ocusing on issues that should be tak en up by r egula tor s, such as: • Oil leak s & e xposur e to oil fume s • R es ponses t o cr e w complaints • T esti ng pr ocedur es f or c abin air • Modific ati on me asur es necessary t o r emedy fume c ont amina tion (b) Cr ew and pas senger c ompartment air must be free fr om harmful or hazar dous c oncentr ati ons of g ases or v apour s … (c) Ther e must be pro visions made to ensur e that the conditi ons described in par a B … ar e me t aft er r easonably pr obable f ailur e or malfunctioning of the venti la ting , heati ng , pr essuriz ati on or other s ys t ems and eq uipment. RECOMMENDA TIONS // CASA ’S VIEW // CASA outl ined in a submission its vie w s on air quali ty on the Bae 146 air cr aft. Acc or ding t o the authority: A t eam of Austr alian medic al e xperts r eview ed the tes t methods and results and has declar ed that ther e is no con taminan t pr es ent in the cabin envir onment that will induce an y long term or permanent ef f ects on the passenger s or cr ew s. In partic ular , at no time w as tricr e s ylphosph at e (T CP) ever id entified in an y sample g ather ed in an Austr alian air cr aft. It is beli ev ed the quality of the air to meet certific ati on st and ar ds f or this type of air cr aft should be t est ed by Gas Li quid Chr omatogr aph y to det ermine lev els of or g anophosphat es and their int er action with h y droc arbons/volati le org anic c ompounds in the ambient cabin air . Action R ecommend ed: EP AAQ FORMED 2007 // EP AA Q w as unable to r each definitiv e conclusions sa ying it is an ar ea of r esea r ch wher e “r ea sonable people’ s views c an diff er ” . CASA consider ed it wouldn’t pr opose an y major poli cy or r egulat ory decisions bas ed on that evidence. It also not ed man y of the EP AAQ’ s r ecommendati ons f ell outside the ambit of CASA ’ s functi ons set out in the Civil A viation Act 1988 (Cth) Civil A viation Adviso ry Publication (CAAP) advises: (c) smok e, to xic or no xious fu mes inside the air cr aft is c onsider ed a major def ect F AA r e sponse to 2002 CA QPCCA r eport acknowledg e s: “F AA rulemaking has not k ept pace with public expect ation and c oncern abou t air quality and does not af f or d expli cit pr otect ion from part icula t e mat ter and other chemic al and biologic al hazar ds. No pr esent airplane de sign fulfills the int ent of 25.831 because no airplane design incorpor at es an air c ont aminant monit oring s ys t em to ensur e the air pr ovided is fr ee of haz ar dous c ont aminants. ” (F ed er al A via tion Adminis tr ati on, 2005) EP AA Q r eport, CASA said: Cont aminati on of air cr aft c abin air b y bleed air – a r evie w of the evidence (up t o Sept ember 2009) The panel’ s inability t o r each definiti ve concl us ions highlights the f act that this i s an ar ea of resear ch wher e r easonable people’ s view s can diff er . In the ci rc ums t ances, E ASA f ound: • a c aus al r elationship betw een the r eported he alth s ymptoms and oil /h ydr auli c fluid c ont amination has not be en est ablished. REGULA T OR RESPONSES // OTHER REPORTS // Cr anfield Univ ersity : Ar e ther e org anophos ha t es in cabin air? • In o ver 95% of the cabin air samples, wer e f ound. . E AS A s tudy 2017: Final R eport Pr eliminary Ca bin Air Quality Measur emen t Campaign • Study r es ults indic at e that under r outine air cr aft oper ations, • In mor e than 95% of all cabin air samples, • In c onclusion: “ ... A conti nu ati on of the pr evious mea sur ement series is also not c ons ider ed as cons tructive, since T CAC- , which needs to be in ves tig at ed in or der to answer some of the que s tions, …” Is this a “pr e tended” pr oblem? Do we know the isomer s to look f or? SENA TE’S FINDINGS - A TTITUDE OF AIRLINES T O ST AFF’S REA CTIONS T O FUMES // The r es ponse to employ ee s showing s ymptoms of to xicity showed a Inf ormation i ssued to s t af f on the issue has at t empt ed to The basic approach to injur ed st aff appear s to be St af f ha ve bee n . W ork er s ha ve been in conditions that c ontinue to St af f ha ve been , and genuine at t empts at r eh abilit ati on hav e been lacking. A TSB – 32 3 REPORTED EVENTS IN 20 18 // WHY SAMPLE FOR TCP? // T ricr e s yl Pho sphat e ( T CP) is an indicat or of blee d air cont amina tion of air cr aft air • Highly specific to mos t jet turbine oils T o assess risk, ne ed to measur e the lev e l of exposur e to bleed air compo nents • T CP and its isomer s are kno wn neu r oto xins • Import ant indic at or of the pr es ence of all other pyr olysis p r odu cts Because the engine oil manuf actur er s appe ar t o r eport the T CP c ont ent of their products unevenly , Pr of e ssor Chris v an Net ten of the Univer sity of British Columbia analysed the actual T CP con ten t – both tot al T CP s and the rela tive amounts of f our T CP isomer s – in samples of eigh t a viati on eng ine oils and thr ee avia tion h ydr aulic fluids. The t ot al T CP c ont ent of the eight oils r anged f r om 2.2 t o 5.2% (by weigh t), and the tot al T CP c ont ent of each h ydr aulic fluid w as z er o. TCP ISOMER P A TTERNS FROM JET TURBINE OILS // Co n tam i n a ted cabi n a i r sa m p l i n g r e p or t (V N Sa m p l e r ): Please fill in this report if y ou have activat ed the VN S ampler devic e within an air craft cabin /flight deck. Name or Sam pler # Approx’ month ly crew hours flown Approx’ monthly aircraft cycles flown 107B 60 37 Date LCL 2018 A/C type NB Jet Route or FLT No x xxxxxxxxxxxxxx Time of activation LCL 50 min A/C Reg VH - _ _ _ Company report reference , e.g Maint l og, safety report cccccc Phase of flight e.g GND, Eng st art, taxi, cli mb, cze, dsc , app/ldg Cruise & descent Bleeds On or Off On APU, On or Off Off Odour comments Oil, skydrol, fuel , dirty s ocks, gym bag, electr ical etc Oil/dry heated dust Fume comments e.g visible , haze, not visible etc Not visible Contamination comments Likely bleed air? IFE/equipment ? Ovens? et c Likely bleed air or ECS oil contamination Short report: This A/C has ex hibited oily odours late on descent re cently, includ ing on both sectors today . Not noti ced by crew othe r than the Captain. The se mild odou rs are generally trea ted as norm al. This A/C has had recent fume events in volving oil found lea king from the APU. A ir sample take n based o n reasonab le suspicion of the presence of oi l in the air con ditioning. Request con firmation of oil presence in this sample. Post flight, Ca pt’ had an aggravated ches t & dry cough which persisted throu gh the nigh t. Sampling commenced in cruise……… …….. AFAPSTCAS1.0 V an Net t en: Given le vels of TBP & T CP in normal fligh ts ar e us ually close to or below our det ection limit, almost all samples, ex c ept #83, identify a pr oblem. Sample #119. The exposure was calculated on the basis of 64 minutes. It appears however, from the pilot’s no tes, that the bulk of the TCP and TBP might have been collected du ring the last segment of sampling. If this was indeed the case, and using the 35-minute sampling period, the ex posure could have been as hig h as 708 1.4 nanogr am of T CP /m3 and 25 42.9 nanogr ams of TBP / m3. CABIN AIR SAMPLING RESUL TS // Showing maximum total T CP lev el s de tected Study Y ear Country / R egion Ma x. lev el TCP μ g / m3 Number of samples number of aircr a ft number of ev ents Denola 2011 Austr alia 51.3 78 46 individual a/ c 9 incidents smok e odo ur Fo x (PhD) 2012 US 100 ? Single engine study Cr anfield 2011 UK 37.7 100 5 a/ c types ‘minor' fumes in 25 flights Hanhela 2005 Austr alia 49 80 3 a/ c types no c orrelation, but some samples tak en with canopy open Fo x / Malmo 1999 Sw ed en 20.3 1 1 (1) engine test AF AP 2018/19 Austr alia 3.872 19 7 a/ c, 1 type 19 STUDIES MEASURING TCP // 300 di ff erent subs tances – cabin and bl eed air studies Pyrolysed oil 127 + (EASA 20 17) V an Net t en: T CP mak es up only 3% of jet turbine oil - the r ep ort ed v alues should be multiplied by 33 to obt ain exposur e to all engine oil c omponents PILOT EXP ANDED REPORTS // Sample 119 - This sample shows on e of the higher results f or TBP and T CP ye t there w as barely a det ectable odou r during the sampled flight. None of the cabin c rew det ected an odour a t all and the pilots detect ed it only mildly . This air cr aft had a leaking h y dr aulic pressure line, with extensiv e h ydr aulic oil evid ent on the belly of the airc r aft, as sh own in the imag es. Note that the airc r aft had been cleaned only 2 w eek s earlier . P ost incident this air cr aft w as design at ed f o r a furth er w ash " at c omp any con venience". On furth er inv estig ation, en gine oil w as found to be present in the APU compartment dr ain and fumes w ere noted b y the engineers when the APU inlet door was open ed. 5 days later a signifi cant oil fumes event occurred whic h invo lved an a ir return . No cau se was fo und and it was suggested that the odo ur may have been due to "smelly pa ssengers" . One crew member showed a slightly elevate d carboxy haemoglob in level (carbon monoxide) when tested sev eral hours after the event. This air cr aft had also been r eported f or a str ong oily odour on 2 previous recent occ asions. Af ter one of the events, en ginee r s assessed the odour to be due to a tmosph eric oz on e in acc ordance w ith the T rouble Shootin g Man ual. Sample 115 - This sample was tak en on reasonable suspicion of a pr oblem due to recen t occ asional sporadic oily smells. Only one crew member de tected a very mild "dusty" or "dry musty" smell durin g the sampling period. No other cr ew member s d etect ed any odour . Th is air cr aft subsequently had a fumes ev ent 6 w eek s lat er with the crew d escribing a mild "hea ted du st-lik e" odour and then a moder at e "sw eaty sock s" odou r . Upon inv estig ation engineers discov ered o il leaking fr om the APU into the APU air intak e. Contaminated cabin air sam pling report (VN Sampler): Please fill in this report if y ou have activat ed the VN S ampler devic e within an air craft cabin /flight deck. Name or Sam pler # Approx’ month ly crew hours flown Approx’ monthly aircraft cycles flown 114 65 35 Date LCL Oct 2018 A/C type NB Jet Route or FLT No x xxxxxxxxxxxxxx Time of activation LCL 34 min A/C Reg VH - _ _ _ Company report reference , e.g Maint l og, safety report cccccc Phase of flight e.g GND, Eng st art, taxi, cli mb, cze, dsc , app/ldg Cruise & descent Bleeds On or Off On APU, On or Off Off Odour comments Oil, skydrol, fuel , dirty s ocks, gym bag, electr ical etc Bleach/chll rin e like cleanin g fluid Fume comments e.g visibl e, haze, not visibl e etc Not visible Contamination comments Likely bleed air? IFE/equipment ? Ovens? e tc Possible cleaning agent, possible oil Short report: Cabin crew repo rted bleach o r chlorine like od our in fo rward cabin.Fro m row 5 forward. Not dete cted in t he flight de ck. ……… Odour detected in cruise and present until after land ing. One cab in crew also detected a “ sweaty so cks smell”, thi s cab in crew felt nau seous soon after t /off. Ano ther cabin ce w had a hea dache. Neither pilot could smell anythin g unusua l. The VN sampler was startd ap prox’ 10 m in’s before descent un til arrival at the gate. The sampler was run for 34 min’s. The cause was late r attributed by engineer ing to mix ing of twosoap s in the for ward lavatory. Ho wever Captain suspect s contamina ted air . …….. AF APSTCAS 1 . 0 V an Ne t t en: Sample #114 Significan t TBP w as det ect ed as well as a tr ace of T CP . Ag ain, as abov e, a high acut e e xpos ur e could hav e been present during the s ampling time. APU h y dr auli c oil ing estion aligns with det ected TBP APU HYDRA ULIC OIL INGESTION // RA W DA T A SECOND SAMPLE SET // ng /filt er TBP m-TCP mmp -TCP mpp-TCP p-TCP Sample 102 SIM 57.15 5.76 12.88 7.31 2.63 Sample 68 SIM 96.30 <LOD <LOD <LOD <LOD Sample 69 SIM 68.08 <LOD <LOD <LOD <LOD Sample 71 SIM 68.87 0.96 2.00 1.19 <LOD Sample 81 SIM 83.17 <LOD <LOD <LOD <LOD Sample 163 SIM 112.84 1.87 7.09 7.62 3.87 Sample 112-1 SIM 165.19 <LOD <LOD <LOD <LOD 1-Con(Process control) SIM 51.32 <LOD <LOD <LOD <LOD Blank 1 <LOD <LOD <LOD <LOD <LOD Blank 2 <LOD <LOD <LOD <LOD <LOD Blank 3 <LOD <LOD <LOD <LOD <LOD Blank 4 <LOD <LOD <LOD <LOD <LOD LOD: 2.08 0.92 2.36 1.83 0.43 LOSS OF MEDI CAL – REPORT EXTRACTS // Hair sampling confirming a presence of chemic als incl uding tri -cresyl phosphate (T OCP) in his sy stem, I found of fered hi story mos t compel ling and could not exclude the possibil ity of a s y ndrome secondary to c hronic airborne chemi cal exposure. report by Dr propos ed a link between exposures derived from his employment and hi s subsequent symptoms, and concluded with the recommendation that should not fly agai n in an aircraft in w hi ch fume events were possibl e, Report: Opinion: T reating doctor correspondence, Serial cons ultations Enduring and fluctuating sym pt oms of cough and w heeze, but additional non-spec ific, systemic s y mptoms such as malaise and headache. …there w as ev idenc e of tri -c resy l phosphate exposure and organophosph ate exposure in specialist pathology sampling.. Although not a generally acc epted term,…case is consis tent the diagnosis of " aerotoxic syndrome". There are am ple grounds to surmise that s y mptoms are consist ent w ith airborne chemical fumes used in the av iation. There is evidence that in some cases , sym pt oms can endure indefinitely . T reatment is supportiv e. Study o n Aircraft Blee d Air Contaminatio n by Engine Oil Experiment al and Numeric al Investigation of Disperse d Ai r - Oil Two - Phase Flow throug h the Environment al Control System M. Di Matteo, O. Berten, and P . Hendrick Speaker: Mariano Di Matteo [email protected] Air cr a ft C abi n Air Int ernational Co nf erence 2021 15 - 18 Mar ch 2021 Outline 2 In tr od uc tio n Me thodol og y Te s t r e s u l t s Con clu s ion s 3 In tr oduction - En vir on ment al Contr ol S y st em su pplies th e cabin with fr esh air a t a cert ain pr essur e and t e mper a tur e - The air us ed by E CS is obt ained by fil t ering and cool ing the aer o - engin e co m p r es s o r b l e ed a ir - Bl ee d a ir is e xtr act ed fr om the c ompr essor of the aer o - en gin es or th e A PU - A c once rn i s the c on t ami na tion o f the ble ed air by ae r o - engi ne oil 4 In tr oduction Bearing compar tments T GB AGB De - Oiler Scavenge Pumps Overboard V ent P ressur e F ilter P ressur e Pump FC OC AC OC Scavenge F ilter P ressur e Oil Line Scavenge Oil Line V ent Line T GB AGB AC OC FC OC T ransf er GearBox Ac cessor y GearBox Air Cooling Oil C ooling F uel Cooling Oil C ooling Oil T ank De - aerato r Thr ee oil subs ys tems: Stor ag e and supply s ys t em Sca veng e s ys tem V en ting Sy st e m F ailure a t the lev el of the bear ing chamber seal s can lead to con tamination 5 In tr oduction Origin of the tw o- phase flo w of oil and air Aim of this s tudy is t o in ves tig a te t he air - oil tw o - phase flo w t hr ough the full piping s y s t em Pr essuriz ing port c an beco me the pr oblem during tr ansi ents … 6 In tr oduction Ther e ar e thr ee diff er ent e xits f or the air - oil tw o -phase flo w: Engin e le v el: Pr essuriz a tion pipe Ve n t l i n e Air cr aft lev el: En vir onm en t al C on tr ol S y s t em 7 Method ol o gy Experiment al phase: - Dr oplet siz e measur ement a t inlet and outlet of piping s y s t em using t he laser diffr ac tion t echnique P artic le Measur emen t: - Laser Helos -V ario /KR - Measur e dr oplet siz e fr om 0,5 /0,9 t o 175 µm (diamet er) 8 Method ol o gy Experiment al phase Pip in g s y s te m Pip e d iam e t er [mm ] Liqu id (oi l and w at er) flow ra t e [ k g /s ] Air f low r at e [g / s] Str aight 0.5 [m] 38 – 15 – 12 0.007 – 0.014 – 0.028 – 0.083 20 – 25 Str aight 1 [m] 38 – 15 – 12 0.007 – 0.014 – 0.028 – 0.083 20 – 25 Str aight 1.5 [m] 38 - 15 0.028 – 0.083 20 – 25 Str aight 2.5 [m] 38 0.028 – 0.083 20 – 25 Str aight 3 [m] 38 0.028 – 0.083 20 – 25 Str aight 3.5 [m] 38 0.028 – 0.083 20 – 25 Str aight 5 [m] 38 0.028 – 0.083 20 – 25 1x cur ve 90˚ 38 0.007 – 0.028 – 0.083 20 – 25 2x cur ves 90˚ 38 0.028 – 0.083 20 – 25 Method ol o gy Experiment al phase: - Description o f the gr anu lometr y usi ng th e Ro s i n - Rammle r (RR) dis tribution 𝑌 = 1 − 𝑒𝑥𝑝 −𝑥 𝑥 ! " 9 10 -7 10 -6 10 -5 10 -4 10 -3 Droplet size [m] 0 10 20 30 40 50 60 70 80 90 100 Cumulative distribution [Q 3 /%] Exp Theoretical 10 Method ol o gy Experiment al phas e: - Iden ti fica tion of distribution k ey par ameter: - Mean dia met er 𝑥 ! - Spr ea d par amet er n 𝑥 ! Corr esponds to the diameter f or which the 63.2% o f part icle s are smaller 𝑌 = 1 − 𝑒𝑥𝑝 −1 " = 0. 632 𝑛 = 𝑙𝑛 − ln (𝑌 ) 𝑙𝑛 𝑥 𝑥 ! 63. 2% 10 -7 10 -6 10 -5 10 -4 10 -3 Droplet size [m] 0 10 20 30 40 50 60 70 80 90 100 Cumulative distribution [Q 3 /%] Exp Theoretical 63.2% 11 Method ol o gy Numeric al Study The inlet p article siz e dis t ribut ions meas ur ed a r e used as boundary c ondit ions fo r t h e n u m e r i c a l com p u tati o n s . The outlet p article siz e dis t ribut ions ar e used a s va l i d a t i o n d ata for t h e out come of the CFD Case Str aight pipe 0.5 [m] dia met e r 38 [mm] Solver Ans ys F lue nt Tu r b u l e n c e m o d e l 𝑘 − 𝜀 Re a l i za b l e Tu r b u l e n c e m u l t i p h a s e m o d e l Disper s ed Disc r et e phase DPM and DDPM Inlet BC Ve l o c i t y m a g n i t u d e o f c o n t i n u o u s p h a s e Disc r et e phase w all B C W all - film Cont inuous phase ti me St eady Disc r et e phase t ime Tr a n s i e n t 10 -7 10 -6 10 -5 10 -4 10 -3 Droplet size [m] 0 10 20 30 40 50 60 70 80 90 100 Cumulative distribution [Q 3 /%] Inlet Exit pipe 1 m Exit pipe 1,5 m Exit pipe 5 m 12 Re s u l t s Experiment al anal y sis: The str aight pipes slightly impact the dr oplet siz e The pr ese nce of a 90˚ curve r educes the siz e of the dr oplets 13 Re s u l t s 10 -7 10 -6 10 -5 10 -4 10 -3 Droplet size [m] 0 10 20 30 40 50 60 70 80 90 100 Cumulative distribution [Q 3 /%] Exit pipe 0.5 m Theoretical Numerical Experi ment al a nd nu merical re s u l t s at t h e ex i t o f t h e 0 . 5 m st rai g h t p i p e . The nume rical cur v e is obt ained by using the mean diame t er and the s pr ead par ame t er r esult ing fr om the CFD t o define the RR dis tributi on. A good p r ed icti on is shown : The spr ead par amet er pr es ent s a 5 % dif f er ence with the ex pe riment al dat a. 14 Conclusion s and Furthe r Activities Experiment al capabiliti es outc omes: - Str aigh t pipe has s light impact on dr oplet siz e - Pr esence of bends r educes t he siz e of dr oplets - The R osi n- Rammler distribution show s a go od fit with the experimen t al r esult s. This le ads to the identifica tion of the RR par amet er s 𝑥 " and 𝑛 . Ther e f or e, it is possible model the dr oplet dis tributi on whit thes e par a met er s, and it can be used as BC and v alidation f or the numeri cal analysis Numerical out co mes: - The e xperiment al RR distribution is the BCs f or the inlet of the DPM - The pot ential of CFD in pr edicting the dro plet siz e di s tribut ions is pr ov e n - The abili ty to ha v e a distribution at the e xit of the pipe giv es the poss ibili ty to pr edict dr oplet beha v ior f or a complet e cir cuit Furthe r acti vities : - Simul ation of a mor e comple x cir cuit and e xplor e dif f er en t oper ating conditions - Explor e the possibil ity to pr edict in-flight c onditions using si mulations. Aircraf t Ca bi n Air Interna ti onal Conference 2021 (AC A 2021 ) – Proceedin gs Conf erence : On line, 15 - 18 M arc h 202 1 Conf erence Director: Tris tan Loraine Publisher: London, UK: GCAQE (htt ps://gcaqe.org) E dito rs : Dieter Scho lz , Susan Mich aelis How to cite this paper (ISO 690, H arvar d): D UM ALIN , D aniel , 20 2 1. A ircr aft Cabin Air – N euroto xicity: Upd ate and in - de pth analysis . A ircraf t Cabi n A ir Int e rnat ion a l Con fer ence 2021 ( On lin e, 15 - 18 Ma r ch 2021) . Lond on, U K: GCAQE. Availab le from: https : / /doi.o rg / 10.5 281 /ze nod o.4904 610 Rel ated p resen tation: h ttps: //doi. org / 10.52 81/ze nod o. 473 04 1 2 Revi ew p rocess: E ditorial re view . The corre sponding author is marked with *. Pr e vi ous pr e se nta tio n: P reliminary results on 30 subject where pres ented at t he A ircr aft Cabin A ir Int ern ational Conf ere nce 2019 . London, UK: GCAQE. Availab le from : https : //do i. org /1 0.52 81/ze nod o. 4464 5 26 1 Airc r aft Ca bin A ir – Neu rotoxic ity : U pdate and in -D epth A nal ys i s DUMALIN , D a n i el 1* 1 AZ Sint - Jan Brugg e - Oostende AV, Campus Henri Serruys, L ab of Neurophys iology, Department Neurology - Ps ychiatry, O s ten d, B elg ium E-M ail : aerotoxbrain @ pro ximus.be Copyright © 20 21 by author(s) Th is w ork is licensed under the Creative Commons Attri bu tion 4.0 Interna tional License ( CC BY ). http s : // creat ivecommon s . org / licenses /by /4. 0 Abst ra ct Purpose : T he ma jor obj ect i v e of thi s st udy w as t o ex pl ore for p os s i bl e c omm on abnormal qua nti t at ive EEG (qEEG ) and Low - Res ol ut i on El ec trom ag ne ti c Tomog rap hy (L ORETA) measures i n a sel f - selected popula ti on ex pe rie nci ng heal t h proble m s related to cabin air con taminati on . Me th odol og y: Th e EEG w as re c orde d f rom 19 s cal p l oc at i on s , accordi ng to t he I nte rnat iona l 1 0 – 20 Sy s te m, from 70 parti ci pa nts rang i ng i n age from 25 t o 67 ye ars . T he ma jori t y we re pil ot s and fl ig ht a tte ndant s wi th 2 to 42 y ea rs fl y i ng experience wh o wer e s till ac tive or n on - act iv e fo r 6 m onths u p t o 22 y ears . A s mal l g roup of the part i ci pants w ere ei the r freque nt fl y ers o r gr ound c re w. I ndi vi dua ls w ere rec or ded d uring eyes - clos ed (EC B ) a nd e y es - opene d ( EO B ) bas el i nes . Eac h ECB rec o rding w as v i sua lly i ns pected a nd cl as s i fied accor di ng t o the pe rcent ti m e of al pha appea rance and di s tri buti on a cr oss t he s cal p. Q EEG a nal y si s was performed , ca lcula ting g lob al ab solu te and re l at ive powe rs for the del ta , the ta , a l pha and be ta ban ds and int er - an d i nt ra - hemi s pheri c ampli tude asymmetries , coher ences and phas e l ag . LO RETA current s our ces we re als o comput ed fr om 1 t o 3 0 Hz . Fi ndi ng s: A compar ativ e i nte r - indi v i dual study of the EEG , qE EG a nd LORE TA res ul te d i n ide nti fy i ng 4 di st i nct groups . Each part i ci pant co ul d be a ss i g ned t o a pa rti cul ar g roup bas ed on thei r pe rcent ti me o f al pha appea rance a nd di s tri bu- ti on acros s the s cal p i n the EC B EEG an d al pha ba nd pe ak freq uency s ou rce pow er di s t ribut i on. G ro up 1 can be cha rac- terized by a dom i nant post eri or al pha rhyt hm an d show s a max imum al pha band pea k f requency s ource p ow er di s t ri- buti on at the ri ght pos tce ntra l a nd ri ght s uperi o r te mpo ral a reas . Group 2 ca n be cha ract eri z e d by a s ubd omi nant post eri or al pha rhy thm and s hows a m ax i mum a lpha band pe ak fre quency s ource pow er di s tri buti on at the r ight po s t- cent ral and ri g ht s uperi o r te mporal a reas . G roup 3 is repre se nte d by a rare or a bse nt a l pha p res e nce and s h ow s no qEEG o r LO RET A abnormal activ ity i n the al pha b a nd. Group 4 i s repres e nte d by a di ffuse al pha a ct i vit y and a maxi - mum al pha band pe ak freq ue ncy s ou rce power di s t ribut i on i n the a nt eri or ci ng ul ate . Group 1 an d 2 c onta i ns t he l a rg- es t numbe r of s ubj ec ts (82. 9% ), f ol l owe d by g roup 3 wi t h 11. 4% of t he s ubje cts and grou p 4 w i th 5. 7% of t he subj ect s . Discu ssio n : Thes e res ul ts rai s e a l ot of que st i ons tha t ca n be sum mari z ed un de r tw o mai n he adi ng s ; where do the s e res ult s come from and w hat effe ct c an the y hav e ? S ubjec ts ex pos e d to a i rcraft ca bi n ai r can e x peri ence a varied n um- ber of s ym ptoms . Thi s res earc h f ocus es on h ow t he affected corti cal areas may cont ri but e t o s ev eral of t hes e s y mp- Aircr af t Ca bin Air – Neurotox ici ty: Update and in - depth analysi s 2 toms. Fo r this we loo k at th r ee maj or bra in syste ms or n etwo r ks: cognitive br ain netwo r ks, cent ra l v es tibul ar sys tem and l ang uage sy st em. Fir st , t he ar eas wi th the m axi mum source powe r di s tri buti on of g r oup 1, 2 and 4 bel ong to the three core c ogni ti ve brain ne twork s. From th is v i ew poi nt we can e xpe ct cog nit i ve dy sfunc ti ons t hat can v ary a cc ording whi ch areas and the numbe r of a reas that a re a ffect ed i n t hes e net works . S econd ly , t he areas wi th the maximum source pow er dis tri buti on of gr oup 1 an d 2 a re part o f t he cent ral v es ti bul ar sy stem i n the non - domina nt ri gh t - hemi s phere . Th i s not onl y means tha t bal ance is sues c an ari se but al so hi gh - leve l co rtic al dy s funct ions i nvol vi ng spa - tial c ogn itio n, in clud ing self - body perce pti on, v erti cal ity percept ion, orie ntat ion, nav igati on an d spat ia l m emory . T h ir dly, w hen looki ng at t he l anguag e sys tem an d the resul ts we woul d not ex pect any l ang uag e rel ate d sy mptoms si nce l ang uage i s in t he domi nant left - hemi sphe re for the m aj orit y of pe opl e, ev en i n le ft - handed pe ople. Res earch has show n that ha nded nes s de termi ned by ques ti onnai res are n ot a re liable in d ica tor to de te r min e th e la te r alit y o f la ngua ge a nd that la nguag e repre sent ation ma y be bes t cons ide red as c onti nuous rat her than di c hotomous . MRI DT I tract ography st ud ies have demo nst r ated that ma ppi ng cort ica l pat hwa ys is a bet te r , non - in vasive m ethod, to d eter- mi ne l ate rality of l ang uag e and has s hown tha t lang uage can al s o be bil ateral ; ei the r bil a te ral l eft domi nant or s ym- metrical. In these l a t ter c ases we ca n expe ct l ang uag e recept ion a nd un de rsta nding dys funct ions f or subject s i n g roup 1 and 2. In s ummary thi s c an hel p to ex pl a in t he vari abili ty of s ympt oms a cross subj ects whi ch depends not onl y o n the number of a reas affect ed but a ls o o n the l at eral it y of l ang uag e and v esti bula r syst em. To try a nd answ er whe re these results come from a search o f li t erature re la ted t o the chol i nergi c s y ste m w as conducte d, s inc e it has been e s- tabl is h by ma ny aut hors tha t ex posure to organophos phat es, whi ch affe ct t he chol ine rgic s ystem, a re prese nt i n ai r- craft ca bin ai r. Many olde r e xperi ment al st udie s hav e s how n that acet yl chol ine modula tes the al pha rhy thm . I n sma ll dos e s t he frequency and am pli tude of alpha incre ase , w hile a la rge dos e suppres ses the alpha act ivi ty. S tudi es on acci dent al expos ure of organop hos phate ba se d pe st ici des hav e s hown t hat i n the acute p hase acet yl chol ine i n t he blood i s inc rea sed a nd t hat the E EG s hows a n a bs ence o f al pha act iv i ty. I n the recov ery pha se the bl ood lev el of ace- ty lchol i ne decre ases t o normal leve ls whil e a gradua l ret urn of alpha acti v it y is obse rved. Thes e fi nd i ng s a re con sis t ent wi th t he qE EG res ult s s howi ng vari ation i n al pha power a nd fre quency , and the p res ence o f or ab se nce of abn ormal current s ou rce dens it y i s relat ed to the pe ak a lpha frequency . Ot her st udie s on t he di st ributi on of choli nerg i c compo- nents seem to i ndi cate a rela ti onshi p bet wee n max imum regi onal di st ributi on and m axi mum a l pha ba nd peak fre - quency sou rce p owe r dis tri buti on . His toch emical studies i llustrate s that the maxi ma l re gion al d ist r ib u tio n of a cet yl - cho linest er ase (AchE) co rres ponds to t he max i mum s ource p ower i n gr oup 1 an d 2. A rec ent [1 8F ]F EOBV PET t race r study i l lus trates that the m a xima l r eg ion al dis tr ib ut io n of the v es ic u l ar ac et ylc hol i ne t rans port er (V AC hT) corre sponds to t he max i mum source powe r in g roup 4. Further, a clinical exampl e of a frequent fl y er se ems to i n di cat e t hat cont in- ued ex posure ov er a pe ri od of 6 y ears le ads t o chang es in t he EEG , qEEG and LO RE TA . Ini ti all y this subj ect showe d ch ar ac ter istic s typ ica l o f gr ou p 1 an d later on ch ara cter ist ic s of group 3. Sign if ican ce : The s e res ult s i n combi nati on wi th othe r studi es provi de s upport for biol og ica l proba bi lit y of chol ine rgi c dys functi on due t o expo su r e of o rganoph os phate s l eadi ng to dose depende nt neur ophys iol og ica l change s cons is te nt wi th current findi ng s a nd related cog nit i ve, l ang uage and v es ti bul ar dys functi ons. Research Limitati ons: In spi te of t he fact tha t thi s st udy pres ent s i nte rest i ng fi nding s consi stent wi th ot her rese arch int o the choli nerg ic s ys te m and i ts dys functi ons , i t ha s its lim ita t ion s. De spite th e fac t that it su gge sts a po ssible d o se depende nt rel at ions hip, the re is the lack o f availa ble data on the l evels to whi ch each m ember of t his popula ti on was ex posed. In orde r to furthe r ex pla in t he v ar i abi li t y of s ym ptoms addi tional analy sis of the dat a is n e eded t o rela te t he nature and deg ree of sy mpt oms t o the ex tent of a reas affect ed fo r each i ndiv i dual . Thi s w ill however ha ve its lim ita- ti ons due t o a l ack of r elia b le informa ti on on t he l ate ral ity of l ang uag e and v es ti bula r syst em. Keywords EEG , Q EEG , L ORETA , ac e tylch olin e, ac ety lcho line st era se, ve sicu lar , t rans port er, ch olin erg ic sy stem , n eu ro tr ansmissio n Airc ra ft C a bin Air In tern atio na l C onf er enc e 2021 3 Lis t of Symbol s Ach Ac ety lch o lin e AchE Ac ety lch o lin e ste r ase DTI Di ffus ion Te nsor Im ag ing ECB Eye s -C l os ed B ase lin e EEG Elect roencepha log raphy EOB Ey es - Opened B aselin e MRI Mag net ic Res onance I magi ng LOR ETA Low - Res ol uti on El ect romag ne ti c Tomog raph y QEEG Q uanti fi ed El ectroe ncephal ography VAC hT Ves i c ula r acet yl choline trans porter [18F]F EO BV 18F - fluor oe thox yb enz ove sa mi col 15 -18/03 /2021 1 Air cr a ft Cabin Air Conf er ence 2021 Aircraft Cabin Air – Neurotoxicity: Update and in-Depth Analysis Daniel Dumalin | [email protected] Lab of Neurophysiology | qEEG – ERP az sint-j an brugge-oostende av – campus Henri Serruys, Belgium 15 -18/03 /2021 2 Air cr a ft Cabin Air Conf er ence 2021 Neur oph y siology qEE G – ERP - EP • qEE G 15 -18/03 /2021 qEE G - Spe ctr al Analysis, T opogr aph y , Sour ce Localisati on 3 Neur oph y siology Amplitud e Asymmetry Absolut e Power Alpha Theta Delta Beta Eyes Closed Open 15 -18/03 /2021 4 Air cr a ft Cabin Air Conf er ence 2021 Pr eliminary R esul ts T ot al subjects: 70 15 -18/03 /2021 Neur oph y siology - Sub jects 5 • Subjects  70  Pilots, Fligh t A t t endan ts Fr equen t Fly er s, Gr ound Cr e w  25 -67 y ear s of ag e, a ver ag e 48 y ear s ( ± 10.5)  2-42 y ear s of fl ying  Activ e or Non-activ e f or 6 mon ths – 22 y ear s Neur oph y siology 15 -18/03 /2021 Gr oup 1 – Dominant Alpha 6 Gr oup 1 T ot al subjects: 37 of 70 The ta Alpha > 2.576 SD > 4.5 SD 8 Hz 8 Hz Eyes Closed Open Eyes Closed Open 15 -18/03 /2021 Gr oup 2 – Sub dominant Alpha 7 Gr oup 2 T ot al subjects: 21 of 70 > 2.576 SD Alpha Bur s t > 1.960 SD 11 Hz 11 Hz Alpha Full EEG α-Bursts Full EEG α-Bursts 15 -18/03 /2021 Gr oup 3 – Rar e Alpha 8 Gr oup 3 T ot al subjects: 8 of 70 Delta The ta Alpha Bet a Group 1 2 3 Group 1 2 3 > 1.960 SD > 2.576 SD 11 Hz 15 -18/03 /2021 Gr oup 4 – Diffuse Alpha 9 Gr oup 4 T ot al subjects: 4 of 70 > 2.576 SD 12 Hz Bet a 1 12 Hz T6 Fz T6 Fz 11 Hz Alpha 15 -18/03 /2021 Gr oup Dis tri bution 10 Gr oup Dis tribution T ot al subjects: 70 • Gr oup 3  Rare or ab sent Alpha  Pilot, Fligh t A t ten dan t Fr equen t Fl yer , Groun d Cr ew • Gr oup 2  Subdominant Alpha  R-P ost-cen tral, R-Superior T empor al  P eak Fr equen cy: 8-12 Hz  Pilot, Fligh t A t ten dan t Fr equen t Fl yer , Groun d Cr ew • Gr oup 1  Dominant Alpha  R-P ost-cen tral, R-Superior T empor al  P eak Fr equen cy: 7-14 Hz  Pilot, Fligh t A t ten dan t Fr equen t Fl yer , Groun d Cr ew 82.9% 52.9% 11.4% 30.0% 5.7% 52.9% 30.0% 11.4% 5.7% • Gr oup 4  Diffuse Alpha  Ant erior C ingula te  P eak fr equen cy: 9-12 Hz  Pilot, Fligh t A t ten dan t 15 -18/03 /2021 11 Air cr a ft Cabin Air Conf er ence 2021 Connecting the dots [Document text truncated for crawler view.]