Aircraft Cabin Air & Water Contamination/Quality – An Aircraft Systems Engineering Perspective

AIRCRAFT DESIGN AND SYSTEMS GROUP (AERO) Aircraft Cabin Air & Water Contamination/Quality – An Aircraft Systems Engineering Perspective QCAQE – Global Cabin Air Quality Executive SEVENTH ANNUAL FORUM and INFORMATION EXCHANGE London, 31st March – 2nd April, 2014 Dieter Scholz Hamburg University of Applied Sciences https://doi.org/10.5281/zenodo.17961958 GCAQE Annual Forum London, 31.03. - 02.04.2014 Dieter Scholz: Aircraft Cabin Air Contamination/Quality – An Aircraft Systems Engineering Perspective 01.04.2014, Slide 1 Aircraft Design and Systems Group (AERO) Abstract Aircraft Cabin Air & Water Contamination/Quality – An Aircraft Systems Engineering Perspective Air conditioning in jet aircraft depends today on bleed air from the engines or APU (apart from the B787). Engine oil with harmful anti wear additives can get into the cabin air. This can be a risk to passengers and crew. The question about "aircraft cabin air contamination" can be related to "aircraft potable water contamination". Aircraft water contamination can in theory be due to a potable water pressurization system with bleed air. Findings are that also the potable water on board can be contaminated from engine oil. It depends on the aircraft system architecture. Examples are given: Potable water contamination from engine oil via bleed air is possible on Airbus A320, A340, (not on the A380) and on Boeing 737, to name a few. Hydraulic reservoirs are connected via bleed lines with the potable water tanks. Pressurized air is in free contact with the hydraulic fluid surface. But, in flight, hydraulic fluid would need to flow upstream and opposite sense through two check valves to get into the bleed line (A320). This is not plausible. On the ground, however, contaminated air with remaining pressure in the reservoir (about 3.5 bar) could flow downstream – but only if check valves allow for wrong flow direction. This is unlikely. This seems to be the scientific way forward: Look for oil contamination in all rotating machinery: engine, APU, air cycle machine (ACM), electrical compressor (B787 has air bearings!). Look for all possible paths on which oil can get in contact with people on board. Today most engine oil contains harmful substances. As long as this is the case it has nothing to do in the aircraft when only the slightest chance exist these substances get in contact with people (via air, water, …). Take a systems engineering view: Think in system boundaries. Argue as simple as possible! GCAQE Annual Forum London, 31.03. - 02.04.2014 Dieter Scholz: Aircraft Cabin Air Contamination/Quality – An Aircraft Systems Engineering Perspective 01.04.2014, Slide 2 Aircraft Design and Systems Group (AERO) Contents Aircraft Cabin Air & Water Contamination/Quality – An Aircraft Systems Engineering Perspective • Introduction •Air and Water – Contamination Hazards • Aircraft Systems Investigated • Systematic Solution • Summary GCAQE Annual Forum London, 31.03. - 02.04.2014 Dieter Scholz: Aircraft Cabin Air Contamination/Quality – An Aircraft Systems Engineering Perspective 01.04.2014, Slide 3 Aircraft Design and Systems Group (AERO) Contents •Introduction • Air and Water – Contamination Hazards •Aircraft Systems Investigated • Systematic Solution • Summary Aircraft Cabin Air & Water Contamination/Quality – An Aircraft Systems Engineering Perspective GCAQE Annual Forum London, 31.03. - 02.04.2014 Dieter Scholz: Aircraft Cabin Air Contamination/Quality – An Aircraft Systems Engineering Perspective 01.04.2014, Slide 4 Aircraft Design and Systems Group (AERO) Introduction Definition: Aircraft Cabin Air A mixture of outside and recirculated and filtered air. In unpressurized aircraft cabins the air is at ambient pressure. In pressurized cabins the air is at a pressure equivalent to below 8000 ft (referring to the ICAO Standard Atmosphere). In most aircraft, the air temperature is controlled. Aircraft flying at high altitude usually show low relative humidity. Adapted from: http://aircrewhealth.com/Topics/hazards/cabinair.htm Definition: Aircraft Systems A combination of inter-related items arranged to perform a specific function on an aircraft. SCHOLZ, Dieter: Aircraft Systems. In: DAVIES, Mark: The Standard Handbook for Aeronautical and Astronautical Engineers. New York : McGraw-Hill, 2003 GCAQE Annual Forum London, 31.03. - 02.04.2014 Dieter Scholz: Aircraft Cabin Air Contamination/Quality – An Aircraft Systems Engineering Perspective 01.04.2014, Slide 5 Aircraft Design and Systems Group (AERO) Introduction Definition: Contamination The process of making a material unclean or unsuited for its intended purpose, usually by the addition or attachment of undesirable foreign substances. Adapted from: http://en.wiktionary.org/wiki/contamination The presence of a minor and unwanted constituent (contaminant). Related to health: A harmful intrusion of toxins or pathogens e.g. in food, water, or air. Adapted from: http://en.wikipedia.org/wiki/Contamination Definition: Quality Degree to which a set of inherent characteristics fulfills requirements. ISO 9000 GCAQE Annual Forum London, 31.03. - 02.04.2014 Dieter Scholz: Aircraft Cabin Air Contamination/Quality – An Aircraft Systems Engineering Perspective 01.04.2014, Slide 6 Aircraft Design and Systems Group (AERO) Introduction http://bloga350.blogspot.com.ar/2012/11/a350-xwb-cabin-air-quality-will-make.html GCAQE Annual Forum London, 31.03. - 02.04.2014 Dieter Scholz: Aircraft Cabin Air Contamination/Quality – An Aircraft Systems Engineering Perspective 01.04.2014, Slide 7 Aircraft Design and Systems Group (AERO) Introduction Requirement: SAE 1796: Engine Bleed Air Systems for Aircraft (1987, A in 2007, B in 2012) Bleed Air Quality : Requirements should be imposed on the engine manufacturer regarding the quality of the bleed air supplied to occupied compartments. Under normal operating conditions: The engine bleed air shall be free of engine-generated objectionable odors, irritants, and/or toxic of incapacitating foreign materials. Following any type of engine … failure , the engine bleed air shall not contain the above substances to a harmful degree. … or bleed air systems should incorporate a bleed air cleaner. Other Requirements: FAA Part 25 / CS-25, SAE AIR 1539: Environmental Control System Contamination. Not further discussed here. GCAQE Annual Forum London, 31.03. - 02.04.2014 Dieter Scholz: Aircraft Cabin Air Contamination/Quality – An Aircraft Systems Engineering Perspective 01.04.2014, Slide 8 Aircraft Design and Systems Group (AERO) air air, combustion products air fueloil gray water water Think: system boundaries Think: systems engineering food radiation waste hydraulic fluid Introduction bleed air systems GCAQE Annual Forum London, 31.03. - 02.04.2014 Dieter Scholz: Aircraft Cabin Air Contamination/Quality – An Aircraft Systems Engineering Perspective 01.04.2014, Slide 15 Aircraft Design and Systems Group (AERO) Aircraft Systems Investigated - Bleed Air to Cabin Overview (1) cabin cabin GCAQE Annual Forum London, 31.03. - 02.04.2014 Dieter Scholz: Aircraft Cabin Air Contamination/Quality – An Aircraft Systems Engineering Perspective 01.04.2014, Slide 16 Aircraft Design and Systems Group (AERO) Aircraft Systems Investigated - Bleed Air to Cabin Overview (2) Adapted from FCOM A320 50 % 50 % recirculation outflow valve hot cold warm GCAQE Annual Forum London, 31.03. - 02.04.2014 Dieter Scholz: Aircraft Cabin Air Contamination/Quality – An Aircraft Systems Engineering Perspective 01.04.2014, Slide 17 Aircraft Design and Systems Group (AERO) Aircraft Systems Investigated - Air Conditioning Pack (1) AMM A320 Liebherr Aerospace GCAQE Annual Forum London, 31.03. - 02.04.2014 Dieter Scholz: Aircraft Cabin Air Contamination/Quality – An Aircraft Systems Engineering Perspective 01.04.2014, Slide 18 Aircraft Design and Systems Group (AERO) Air Cycle Machine Aircraft Systems Investigated - Air Conditioning Pack (2) AMM A320 • An Air Cycle Machine (ACM) is a high energy rotor device. • An ACM may need some form of lubrication (=> oil) • Lubrication needs will be much smaller than in aircraft engines. • Use of air bearings is possible. GCAQE Annual Forum London, 31.03. - 02.04.2014 Dieter Scholz: Aircraft Cabin Air Contamination/Quality – An Aircraft Systems Engineering Perspective 01.04.2014, Slide 19 Aircraft Design and Systems Group (AERO) Aircraft Systems Investigated - Engine Overview K. Aainsqatsi, Wikipedia.org GCAQE Annual Forum London, 31.03. - 02.04.2014 Dieter Scholz: Aircraft Cabin Air Contamination/Quality – An Aircraft Systems Engineering Perspective 01.04.2014, Slide 20 Aircraft Design and Systems Group (AERO) Aircraft Systems Investigated - Engine Overview GCAQE Annual Forum London, 31.03. - 02.04.2014 Dieter Scholz: Aircraft Cabin Air Contamination/Quality – An Aircraft Systems Engineering Perspective 01.04.2014, Slide 21 Aircraft Design and Systems Group (AERO) Aircraft Systems Investigated - Engine Overview A320 Training Manual: CFM 56-5 GCAQE Annual Forum London, 31.03. - 02.04.2014 Dieter Scholz: Aircraft Cabin Air Contamination/Quality – An Aircraft Systems Engineering Perspective 01.04.2014, Slide 22 Aircraft Design and Systems Group (AERO) Aircraft Systems Investigated - Engine Overview RR Trent 900 GCAQE Annual Forum London, 31.03. - 02.04.2014 Dieter Scholz: Aircraft Cabin Air Contamination/Quality – An Aircraft Systems Engineering Perspective 01.04.2014, Slide 23 Aircraft Design and Systems Group (AERO) Aircraft Systems Investigated - Labyrinth Seal A380 Technical Training Manual Positive air pressure and flow against the oil pressure should prevent the seals from leaking. The CAA has already taken remedial action to help operators of particular aircraft reduce the incidence of fume events e.g. engine oil servicing procedures and engine sealing modifications. https://www.gov.uk/government/publications/cabin-air-quality-faq GCAQE Annual Forum London, 31.03. - 02.04.2014 Dieter Scholz: Aircraft Cabin Air Contamination/Quality – An Aircraft Systems Engineering Perspective 01.04.2014, Slide 24 Aircraft Design and Systems Group (AERO) Aircraft Systems Investigated - Engine Air and Oil System FCOM A340: Engine Air System FCOM A340: Engine Oil System GCAQE Annual Forum London, 31.03. - 02.04.2014 Dieter Scholz: Aircraft Cabin Air Contamination/Quality – An Aircraft Systems Engineering Perspective 01.04.2014, Slide 31 Aircraft Design and Systems Group (AERO) Aircraft Systems Investigated - Cabin Air Distribution GENFAM A320: Cabin Air Distribution GCAQE Annual Forum London, 31.03. - 02.04.2014 Dieter Scholz: Aircraft Cabin Air Contamination/Quality – An Aircraft Systems Engineering Perspective 01.04.2014, Slide 32 Aircraft Design and Systems Group (AERO) FCOM A340: Potable Water System Description Aircraft Systems Investigated - Potable Water System GCAQE Annual Forum London, 31.03. - 02.04.2014 Dieter Scholz: Aircraft Cabin Air Contamination/Quality – An Aircraft Systems Engineering Perspective 01.04.2014, Slide 33 Aircraft Design and Systems Group (AERO) Aircraft Systems Investigated - Potable Water System A380 GCAQE Annual Forum London, 31.03. - 02.04.2014 Dieter Scholz: Aircraft Cabin Air Contamination/Quality – An Aircraft Systems Engineering Perspective 01.04.2014, Slide 34 Aircraft Design and Systems Group (AERO) Aircraft Systems Investigated - Potable Water Tank Pressurization Training Material A320: Potable Water System pressurization. GCAQE Annual Forum London, 31.03. - 02.04.2014 Dieter Scholz: Aircraft Cabin Air Contamination/Quality – An Aircraft Systems Engineering Perspective 01.04.2014, Slide 35 Aircraft Design and Systems Group (AERO) Aircraft Systems Investigated - Potable Water Tank Pressurization • Possible bleed air contaminations could reach the potable water passing a filter and a check valve (in flow direction). GCAQE Annual Forum London, 31.03. - 02.04.2014 Dieter Scholz: Aircraft Cabin Air Contamination/Quality – An Aircraft Systems Engineering Perspective 01.04.2014, Slide 36 Aircraft Design and Systems Group (AERO) Aircraft Systems Investigated - Hydraulic Reservoir Pressurization • Hydraulic reservoirs are connected via bleed lines with the potable water tanks. • Pressurized air is in free contact with the hydraulic fluid surface. • In flight, hydraulic fluid would need to flow upstream and opposite sense through two check valves to get into the bleed line. • On the ground, contaminated air with remaining pressure in the reservoir (≈3.5 bar) could flow downstream – but only if check valves allow for wrong flow direction. GenFam, A320 GCAQE Annual Forum London, 31.03. - 02.04.2014 Dieter Scholz: Aircraft Cabin Air Contamination/Quality – An Aircraft Systems Engineering Perspective 01.04.2014, Slide 37 Aircraft Design and Systems Group (AERO) Aircraft Systems Investigated - Hydraulic Reservoir Pressurization GenFam, A320 Reservoir Pressurization Manifold GCAQE Annual Forum London, 31.03. - 02.04.2014 Dieter Scholz: Aircraft Cabin Air Contamination/Quality – An Aircraft Systems Engineering Perspective 01.04.2014, Slide 38 Aircraft Design and Systems Group (AERO) Aircraft Systems Investigated - Bleedless B787 Boeing: AERO GCAQE Annual Forum London, 31.03. - 02.04.2014 Dieter Scholz: Aircraft Cabin Air Contamination/Quality – An Aircraft Systems Engineering Perspective 01.04.2014, Slide 39 Aircraft Design and Systems Group (AERO) Aircraft Systems Investigated - Bleedless B787: APU GCAQE Annual Forum London, 31.03. - 02.04.2014 Dieter Scholz: Aircraft Cabin Air Contamination/Quality – An Aircraft Systems Engineering Perspective 01.04.2014, Slide 40 Aircraft Design and Systems Group (AERO) Contents • Introduction • Air and Water – Contamination Hazards • Aircraft Systems Investigated •Systematic Solution • Summary Aircraft Cabin Air & Water Contamination/Quality – An Aircraft Systems Engineering Perspective