Contaminated Air and FAA Airworthiness
Source: Aviation Contaminated Air Reference Manual
US Airworthiness Directives © 10th April 2008 by Susan Michaelis Three ADs raised by the US FAA regarding potential contaminated air are worth highlighting. The first concerned specific maintenance actions rather than the obvious need for ADs to be raised, similar to those for the BAe 146 in connection with inspection and maintenance of possible oil contamination to all aircraft. The 2000 AD raised by the FAA covering the MD81-MD90 series aircraft required a specific action due to, ‘reports of smoke and odor in the passenger cabin and cockpit due to hydraulic fluid leaking into the APU inlet, and subsequently, into the air conditioning system.’ [85] The second one issued by the FAA covered certain Rolls Royce or Allison Engine turbofan engines in 2001. This AD covered the requirement for, ‘initial and repetitive inspections for bearing material contamination of the engine oil system. This amendment is prompted by reports of rapid failures of the No. 1 bearing. The actions specified in this AD are intended to detect the rapid failure of the No. 1 bearing, which could result in smoke in the cabin and an uncommanded in-flight engine shutdown.’ [86] The third AD issued by the FAA is interesting. While the FAA did not raise a similar AD to CASA and the CAA mandating the March 2001 BAe SB 21-150, it did however follow suit on the second one, albeit 18 months after the UK CAA and Australian CASA and the Canadian Regulator issued their AD against BAe SB 21-150. This significant mandatory FAA AD was issued in July 2004. [87]
‘This amendment adopts a new airworthiness directive (AD), applicable to all BAE Systems (Operations) Limited Model BAe 146 series airplanes, that requires repetitive detailed inspections of the inside of each air conditioning sound-attenuating duct, and corrective actions as necessary. This action is necessary to prevent impairment of the operational skills and abilities of the flight crew caused by the inhalation of agents released from oil or oil breakdown products, which could result in reduced controllability of the airplane. This action is intended to address the identified unsafe condition.’
It is noteworthy that the FAA has not implemented the other 2 ADs issued for the BAe 146 regarding oil contamination and parts that are connected to this as shown in Chapter 17. Additionally, it is of concern that such ADs have not been raised in the US, UK or anywhere else specifically dealing with contaminated air on other aircraft types, as it is now acknowledged that all aircraft leak oil to varying degrees as a part of the design of bleed air systems.
As of 2007 most of the key recommendations and stated objectives of the AOMs and the FODCOMS, including the further recommendations of FODCOM 21/2002, have not been actioned by airlines as they have not educated pilots and crews. Most crews are still uninformed of the content, objectives and recommendations of the FODCOMS, AOM and SBs. The FODCOM recommendation, ‘1.5.2 a) A commander’s review of the in-flight incident. This should include consultation with the flight and cabin crew,’ is simply not occurring apart from on very rare occasions. An example of the system failing to work is a fume event in late 2005 on an A320 on the UK contaminated air database. The pilot advises that oxygen was not used despite a, ‘strong smell of oil mist’ and that guidance is needed from the airline as it is a difficult decision to make to, ‘don oxy masks and divert, just for a 'smell'.’ The CAA messages are clearly not getting through as can be seen by closely reviewing the events on the UK contaminated events database in Appendix 2.
In 2004, one of the UK pilot unions, BALPA advised the CAA and UK Government at the Aircraft Health Working Group (AHWG) meeting that it was concerned about crews failing to report contaminated air events. More detail can be seen on this in Chapter 12 on the frequency of events. BALPA stated there was still strong evidence several years after the CAA had put out the FODCOMs and ADs relating to contaminated air, showing that the system was not working. BALPA asked the CAA to jointly run a, ‘Report it Campaign’ to educate all pilots on the need to report all contaminated air events. However, Mr Tom Hamilton of the CAA Safety Regulation Group advised that, ‘the CAA did not have any evidence of under reporting from aircrews and that the existing reporting arrangements appeared to be working satisfactory. He was concerned that the ‘Report it Campaign’ might undermine the current reporting process.’ [88] This clearly shows the CAA’s complete unwillingness to accept the system is not working despite strong evidence shown in Chapter 12 and Appendix 2. As the CAA fails to listen to union representatives it could therefore be assumed that the CAA is protecting the industry that it is entirely funded by.
Flight Safety Aspects of Contaminated Air
Reporting Contaminated Air Events with Samples of Known Events
FODCOM (Flight Operations Department Communication) number 17/2000
FODCOM (Flight Operations Department Communication) number 14/2001 and 21/2002
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References
85. FAA (2000) Airworthiness Directive (AD) 2000-15-17, MD series aircraft. US Federal Aviation Administration, Washington.
86. FAA (2001) Airworthiness Directive AD 2001-08-15: Rolls Royce 3007 series engines. US Federal Aviation Administration, Washington.
87. FAA (2004) Airworthiness Directive AD 2004-12-05: BAE Systems (Operations) Limited Model BAe 146 Series Airplanes US Federal Aviation Administration, Washington. July 14, 2004.
88. CAA: Tom Hamilton, SRG: Minutes of the AHWG meeting 27 October 2004. Available at: http://www.dft.gov.uk/stellent/groups/dft_aviation/documents/page/dft_aviation_612241.hcsp.
