Fire Protection in Aviation

AIRCRAFT DESIGN AND SYSTEMS GROUP (AERO) Fire Protection in Aviation Dieter Scholz Hamburg University of Applied Sciences https://doi.org/10.48441/4427.2348 Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, 06./07. März 2025 Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 2 Aircraft Design and Systems Group (AERO) Fire Protection in Aviation Abstract Fatalities on passenger aircraft have several reasons and occur with different numbers. Fire and smoke on board is not the worst in this comparison, but it deserves attention. Aircraft are designed with multiple redundancies, but undetected manufacturing defects or inadequate maintenance can still be catastrophic. Sorting with respect to flight phase, we have in-flight fires that need to be taken care of by an aircraft system itself. The system is called "Fire Protection" (ATA 26). A fire on the aircraft while it is on the ramp as well as a post-crash fire is taken care of by Aircraft Rescue and Firefighting (ARFF) located at the airport. In-flight fires can be hidden fires (electric circuit), visible fires in the cabin, or from the engine or Auxiliary Power Unit (APU) – a gas turbine in the tail of the aircraft that provides electric power and compressed air. Protection against fire and smoke on board is by prevention, slow growth policy (flame-retardants), detection, and extinguishing. Certification rules on fire protection are in place that regulate the design of the aircraft. Rules are from certification authorities (EASA, FAA, ...) and in addition from aircraft manufacturers (Airbus with its ABD0031). Certification rules on fire protection are revisited regularly and have been written more stringent, but ways to improve safety still exist. As often, a compromise between safety and economics must be found. EASA CS-25.803 "Emergency Evacuation" demands that an aircraft can be evacuated under simulated emergency conditions (doors on one side are closed, ...) within 90 seconds. This is a good but arbitrary standard. Its validity can be challenged, when looking at evacuation with fire and smoke and with other combinations of doors in use. Many emergency landings took place with smoke on board, where it turned out later that the smoke was not from a fire, but from engine oil transported into the cabin and cockpit by means of so-called bleed air from the engines. The problem is a fundamentally wrong design principle applied for the environmental control system (ECS) of all present passenger aircraft (except for the Boeing 787). It is wrong to use (unfiltered) compressed air from the engine (bleed air). Instead outside air must be compressed in dedicated compressors using air from a separate inlet. Smoke and fumes from the engine (or APU) does not require to land As Soon As Possible (LASAP) as in case of a fire. Nevertheless, pyrolyzed engine oil (and hydraulic fluid) is toxic and has caused crew and passengers to get acutely and chronically ill. Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 3 Aircraft Design and Systems Group (AERO) Contents Fire Protection in Aviation •Fatalities on Passenger Aircraft •Aircraft Fire & Smoke: Background •Chemicals / Flame-Retardants •Certification Rules •Airbus ABD0031 •Aircraft Fire Protection (ATA 26) •Safety in the Cabin – Critical Views: RAeS FOG •Aircraft Fire and Evacuation Simulation •Fume Events / Cabin Air Contamination Events (CACE) •Smoke Warning from Cargo Compartment, but No Fault Found (NFF) Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 4 Aircraft Design and Systems Group (AERO) Fatalities on Passenger Aircraft Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 5 Aircraft Design and Systems Group (AERO) 1. Terrorism/Hijacking •Why it ranks high: A few large-scale acts—particularly the events of September 11, 2001—caused extremely high casualties in a single day, overshadowing most other individual accidents. •Key points: Though rare, deliberate sabotage or hijacking can result in catastrophic loss of life. 2. Pilot Error and Loss of Control •Why it ranks high: Over the decades, human factors—including misjudgments, fatigue, poor decision-making, and inadequate response to emergencies—have been among the most persistent causes of accidents. •Key points: Ongoing improvements in training and cockpit automation help reduce such errors, but human oversight remains critical. 3. Controlled Flight Into Terrain (CFIT) •Why it ranks high: CFIT accidents occur when a fully functional aircraft is unintentionally flown into the ground, water, or obstacles. •Key points: Often stems from navigation errors, poor visibility, or breakdowns in pilot–controller communication. 4. Mechanical or Structural Failures •Why it ranks high: Failures in critical systems—engines, hydraulics, airframes—have led to major accidents over the history of aviation. •Key points: Aircraft are designed with multiple redundancies, but undetected manufacturing defects or inadequate maintenance can still be catastrophic. 5. Adverse Weather Conditions •Why it ranks high: Weather-related accidents can involve wind shear, icing, heavy storms, or turbulence. •Key points: Modern forecasting and onboard weather radar have reduced these risks, but sudden phenomena (e.g., microbursts) still pose hazards. Fatalities on Passenger Aircraft Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 6 Aircraft Design and Systems Group (AERO) 6. Fire/Smoke Onboard (In-Flight, On the Ramp, or Post-Crash) •Why it matters: In-flight fires or smoke can rapidly disable critical systems, fill the cabin with toxic fumes, or incapacitate the crew. Even if an aircraft lands safely, smoke and flames can hamper evacuation. •Examples: oIn-flight electrical fires (e.g., Swissair Flight 111) oCargo fires (e.g., ValuJet Flight 592) oPost-crash fires that spread quickly, making escape more difficult (e.g., Saudia Flight 163) 7. Runway Incidents (Excursions/Collisions) •Why it ranks here: Takeoffs and landings are high-risk phases of flight; runway overruns, undershoots, and collisions have led to numerous fatalities. •Key points: The deadliest accident in aviation history (Tenerife, 1977) was a runway collision. Improved runway safety areas, better airport lighting, and advanced alerting systems aim to reduce these incidents. Key points: •Aircraft are designed with multiple redundancies, but undetected manufacturing defects or inadequate maintenance can still be catastrophic. •Fire/Smoke does not cause highest number of fatalities, nevertheless it is important enough to get into the topic Fatalities on Passenger Aircraft Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 7 Aircraft Design and Systems Group (AERO) Important Notes •Overlap of causes: Many fatal accidents stem from a chain of errors or failures rather than a single cause. For example, a mechanical issue might lead to an in-flight fire, which in turn overwhelms the crew and results in a crash. •Statistical variability: The relative ranking can change based on time and location and whether you classify terrorism and sabotage separately from “typical” operational causes. •Continuous improvements: Aviation safety has significantly advanced in all these areas, making accidents increasingly rare despite growing air traffic. Fatalities on Passenger Aircraft Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 8 Aircraft Design and Systems Group (AERO) Aircraft Fire & Smoke: Background Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 9 Aircraft Design and Systems Group (AERO) Flight Phase, Type, Protection •Flight phase: •ramp fire => Aircraft Rescue and Firefighting (ARFF) •in-flight fire => Aircraft System: Fire Protection (ATA 26) •post-crash fire => Aircraft Rescue and Firefighting (ARFF) •Type of fire (in-flight): •engine fire or APU fire => remote extinguishing •hidden fire (e.g. electric circuit) => circuit deactivation •cabin fire => handled by cabin crew (fire extinguisher, smoke hood) •Protection against fire and smoke on board: •prevention •slow growth: flame-retardants (FR) •detection •extinguishing Aircraft Fire & Smoke: Background Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 16 Aircraft Design and Systems Group (AERO) https://www.easa.europa.eu/en/document-library/certification-specifications/cs-25-amendment-27 Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 17 Aircraft Design and Systems Group (AERO) https://www.easa.europa.eu/en/document-library/easy-access-rules/online-publications/easy-access-rules-large-aeroplanes-cs-25 Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 18 Aircraft Design and Systems Group (AERO) Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 19 Aircraft Design and Systems Group (AERO) Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 20 Aircraft Design and Systems Group (AERO) Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 21 Aircraft Design and Systems Group (AERO) Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 22 Aircraft Design and Systems Group (AERO) Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 23 Aircraft Design and Systems Group (AERO) Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 24 Aircraft Design and Systems Group (AERO) https://www.easa.europa.eu/en/document-library/easy-access-rules/online-publications/easy-access-rules-large-aeroplanes-cs-25?page=68 Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 25 Aircraft Design and Systems Group (AERO) https://www.fire.tc.faa.gov/pdf/25-853.pdf Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 32 Aircraft Design and Systems Group (AERO) Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 33 Aircraft Design and Systems Group (AERO) Example Airbus A321 Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 34 Aircraft Design and Systems Group (AERO) Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 35 Aircraft Design and Systems Group (AERO) Source: https://safetyfirst.airbus.com/do-not-wait-to-apply-the-engine-fire-procedure Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 36 Aircraft Design and Systems Group (AERO) There are two types of engine fire: an engine fire (nacelle fire) and tailpipe fire (internal fire). Both types of fire affect the core but must be treated differently. An engine fire (nacelle fire) affects the external part of the engine core but is contained within the engine nacelle. This type of fire can occur on ground or in flight and is usually caused by a malfunction or rupture of a component or pipe, which contains flammable liquids (high-pressure fuel, oil, hydraulic fluid). When these liquids come into contact with hot surfaces on the engine case, such as the high-pressure compressor, combustor, or turbine, they can self-ignite and cause a fire. This type of engine fire can also be caused by rupture of a part of the engine core causing damage to components and pipes, which can lead to a fire. Source: https://safetyfirst.airbus.com/do-not-wait-to-apply-the-engine-fire-procedure Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 37 Aircraft Design and Systems Group (AERO) A tailpipe fire (internal fire) occurs inside the engine core. This type of fire will only occur during the engine start or shutdown sequence. A tailpipe fire occurs when the engine rotates at a very low speed and residual fuel is present in the combustion chamber or turbine area, or if there is an oil leak in the tailpipe of the engine. The risk of tailpipe fire is higher in the case of a second engine start attempt, because residual fuel may remain in the engine after the first attempted engine start. The fire detection system does not detect tailpipe fires, because they occur inside the hot sections of the engine core, and therefore, are outside of the fire detection zone. Flight crews can detect tailpipe fires by observing any abnormal increase in Exhaust Gas Temperature (EGT) during the engine start sequence or if the EGT does not decrease after engine shutdown. Ground crew, cabin crew, or air traffic controllers may also observe a tailpipe fire and must inform the flight crew. In the case of a tailpipe fire, the flight crew must apply the ENGINE TAILPIPE FIRE abnormal procedure from the QRH. This will ventilate the engine, and the airflow will extinguish the fire and remove any residual fuel or vapor from the engine. Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 38 Aircraft Design and Systems Group (AERO) Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 39 Aircraft Design and Systems Group (AERO) Example of engine fire detection system on an A320 aircraft with CFM engines. Source: https://safetyfirst.airbus.com/do-not-wait-to-apply-the-engine-fire-procedure Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 40 Aircraft Design and Systems Group (AERO) Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 41 Aircraft Design and Systems Group (AERO) Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 48 Aircraft Design and Systems Group (AERO) Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 49 Aircraft Design and Systems Group (AERO) Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 50 Aircraft Design and Systems Group (AERO) Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 51 Aircraft Design and Systems Group (AERO) Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 52 Aircraft Design and Systems Group (AERO) Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 53 Aircraft Design and Systems Group (AERO) Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 54 Aircraft Design and Systems Group (AERO) Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 55 Aircraft Design and Systems Group (AERO) Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 56 Aircraft Design and Systems Group (AERO) Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 57 Aircraft Design and Systems Group (AERO) Aircraft Fire and Evacuation Simulation Prof. Edwin Galea, Director, Fire Safety Engineering Group, University of Greenwich https://doi.org/10.5281/zenodo.10730716 Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 64 Aircraft Design and Systems Group (AERO) Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 65 Aircraft Design and Systems Group (AERO) https://www.fzt.haw-hamburg.de/pers/Scholz/dglr/hh/report_2014_10_16_Fire_and_Evacuation.pdf Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 66 Aircraft Design and Systems Group (AERO) Fume Events / Cabin Air Contamination Events (CACE) http://CabinAir.ProfScholz.de Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 67 Aircraft Design and Systems Group (AERO) https://www.fzt.haw-hamburg.de/pers/Scholz/AircraftCabinAirContamination_Flyer.pdf https://www.amazon.de/dp/3446482059 https://d-nb.info/132870338X Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 68 Aircraft Design and Systems Group (AERO) Engine Bearings and Bleed Air From the Jet Engine into the Cabin Based on P&W 2014 Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 69 Aircraft Design and Systems Group (AERO) Lubrication and Sealing of Engine Bearings Based on Exxon 2017 Normal operation of engine seals: 1. The "drain" discharges oil. 2. The "dry cavity" contains oil. 3. Air and oil leak from bearings into the bleed air. => Engines leak small amounts of oil by design! From the Jet Engine into the Cabin Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 70 Aircraft Design and Systems Group (AERO) engine bleed airengine bleed air HEPA Filter HEPA Filter RecirculationRecirculation 50% of air via outflow valve 50% 100% 50% 50% Airbus A320 From the Jet Engine into the Cabin Air Conditioning System Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 71 Aircraft Design and Systems Group (AERO) Distribution of Fluids Engine Oil Hydraulic Fluid Deicing Fluid Fuel Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 72 Aircraft Design and Systems Group (AERO) Contaminants and Their Routes Into the Cabin Distribution of Fluids Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 73 Aircraft Design and Systems Group (AERO) Distribution of Engine Oil Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 80 Aircraft Design and Systems Group (AERO) Engine Oil Colors Cabin Air Duct Black Airbus A320 air conditioning air distribution duct in the cabin. The inside is black from contaminated bleed air. Distribution of Engine Oil Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 81 Aircraft Design and Systems Group (AERO) Engine Oil Colors Cabin Air Duct Black Left: A unused duct supplied new. Right: A ducts that had been installed downstream of the environmental control system air conditioning packs on a BAe 146 passenger aircraft after 26061 flight hours (CAA 2004). Distribution of Engine Oil Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 82 Aircraft Design and Systems Group (AERO) Flow Limiter in Air Conditioning Ducts Flow limiter clogged from pyrolysed engine oil in ducts of the air conditioning system of Boeing 757 aircraft with RollsRoyce RB211-535E4 engines operated by Icelandair (Hansen 2019) compared to a clean flow limiter (top). Distribution of Engine Oil Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 83 Aircraft Design and Systems Group (AERO) Engine Oil Colors Riser Ducts Black Riser ducts and lower cabin air outlet on an Airbus A320 aircraft. The red line close to the cabin floor shows, where the duct was separated and opened. It is black inside from engine oil residue. Video: https://bit.ly/2YXcL3a Distribution of Engine Oil Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 84 Aircraft Design and Systems Group (AERO) Black Residue Settles on the Overhead Bin's Surfaces Left: Cleaning on top of the overhead bins of an Airbus A320 brings to light dirt that is clearly more than dust. The black residue known from the ducts settles also on the bin surface. Picture source: Video: https://youtu.be/uQfA_DiMBS8 Right: Airbus A320 cabin cross section with the upper cabin air outlet releasing potentially contaminated air on top of the overhead bins (Airbus 1999). Distribution of Engine Oil Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 85 Aircraft Design and Systems Group (AERO) Smoke Warning from Cargo Compartment, but No Fault Found (NFF) https://purl.org/aero/PR2023-07-06 https://www.fzt.haw-hamburg.de/pers/Scholz/Aero/AERO_PR_A321-Kabinenluftkontamination/AERO_PR_A321-Kabinenluftkontamination_23-07-06.html Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 86 Aircraft Design and Systems Group (AERO) Cabin Air Contamination, but No Fault Found (NFF) 6 July 2023, Flight TK1668: Air Turnback of an Airbus A321 to Hamburg (HAM) Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 87 Aircraft Design and Systems Group (AERO) Top:2019-08-22, Hawaiian Airlines HA47, A321neo. Bottom: 2019-08-05, British Airways BA-422, Airbus A321. Cabin Air Contamination Event Due to Engine Oil After Technical Fault Other Examples: Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 88 Aircraft Design and Systems Group (AERO) Qe Cout(side) QeC S dt dC VCQCQS eoute =−+ S: source strength in kg/s Qe: effective air flow rate for ventilation in m³/s C: concentration of CO2 or any other substance in kg/m³ in the room Cout: concentration of CO2 or any other substance in kg/m³ outside of the room V: volume of the room SCHOLZ, Dieter, 2020. Aircraft Cabin Ventilation Theory, Memo. Hamburg University of Applied Sciences. https://doi.org/10.31224/osf.io/ac6p8 Ventilation Equation Cabin Air Contamination, but No Fault Found (NFF) Tagung und Fortbildung Brandschutz Rilano, Hamburg-Finkenwerder, Germany Dieter Scholz: Fire Protection in Aviation 06.03.2025, Slide 89 Aircraft Design and Systems Group (AERO) Cabin Air Contamination – Time History Assumed concentration of a contaminant (e.g. engine oil) in cabin air. Strong contamination could be present as visible smoke. The concentration increases over 10 minutes with constant source strength of the contaminant. After this, it is assumed that no contaminant enters the cabin anymore. Cabin ventilation washes the contaminant out. After another 10 to 15 minutes hardly any contamination is left in the cabin air. Cabin Air Contamination, but No Fault Found (NFF)