Report from Mainz, 2020-01-28: Do toxic gases in planes harm personnel and passengers? ======================================================= My comment given on https://purl.org/cabinair/ard-report-video, 2020-01-29 (within the max. 2000 characters) - translated from German. Unfortunately, the comments on this page are merely routed to the TV station and are not displayed. --- It can already be seen from the technical drawings for the bearings of the engine shafts with the seals that small amounts of oil get into the compressor under normal conditions and thus into the cabin. The oil that emerges from the bearing housings can be compared a) with the oil consumption of the engine and b) with the concentration of hydrocarbons in the cabin. A calculation shows that the leakage at the seals in the engine accounts for approximately 1% of the engine's oil consumption. The pollution that accumulates over the life of the aircraft is visible (see video) when the pipes are made accessible. Here you can see clear differences between the pipes that carry bleed air compared to pipes that carry (unpolluted) fan air. Just as clear is the difference between polluted air-carrying air conditioning ducts compared to non-polluted air-carrying ducts for cooling the avionics - Skin Air Ducts (A320). Disregard of regulations: 1.) CS-25.1309 (c) Information regarding unsafe system operating conditions => sensors are required but not available. 2.) CS 25.831 Ventilation: (a) Each passenger and crew compartment must be ventilated ... to enable crewmembers to perform their duties without undue discomfort or fatigue. (b) Crew and passenger compartment air must be free from harmful or hazardous concentrations of gases or vapors. 3.) CS-E 690 (b) Contamination Tests of Bleed Air for Cabin Pressurization or Ventilation => Incoming tests are missing. Disregard of rules of "best practice" that engineers give themselves for their work (supported by companies): SAE AIR 1168-7: "Oil contamination ... can occur in using compressor bleed air from the main engines." "Popular opinion regarding the risk of obtaining contaminated air from the engine may preclude its use for transport aircraft, regardless of other reasons." (With this comment, I would like to briefly add the important things that unfortunately did not find a place in the report.) ---