Aircraft Cabin Air – Quality or Contamination?

All aviation fluids (e.g. oil, fuel, hydraulic fluid) are spilled and subsequently ingested from the ground at airports. Jet engines leak oil internally in small quantities in normal operation by design and potentially in large amounts in failure cases. The oil gets into the engine compressor and via bleed air into the passenger cabin. The same is true for the auxiliary power unit (APU). Hydraulic fluids leak from the landing gear bay via the bottom of the fuselage into the APU inlet. As such, hydraulic fluids can also reach the potable water tank. Technical solutions are necessary: filtration in the recirculation path; better: complete air filtration; much better: a bleed-free air conditioning architecture. What can be done today? Crew members can get informed with a personal chemical detector. Cabin crew can get protected with a breathing mask, used in case of a fume or smoke event. In such cases, pilots can descend to 10000 ft to use direct venting of the cabin and cockpit to make a difference for passengers.