Contaminated Air and Oxygen Not Used
Source: Aviation Contaminated Air Reference Manual
Oxygen is Rarely Being Used © 10th April 2008 by Susan Michaelis The UK Government in 2004 and again in 2005 advised that oxygen was required to be as a precautionary measure in all cases of suspected contaminated air irrespective of the severity of the event. [101][109] However by carefully reviewing the contaminated air events listed in this manual and in the appendices, it is clearly evident that pilots are failing to use oxygen in most contaminated air events. When they are it is only for a short duration and often by 1 pilot only. The UK AAIB stated in a report regarding a B757 incident in 2003 (see Chapter 11) that with regard to the pilots decision to use oxygen, ‘experience shows that pilot's well-being and judgement can be affected by exposure to engine oil fumes. Had they not taken this action, the subsequent handling difficulties on the final approach to London Gatwick could have been further compounded, increasing the degree of risk.’
The Australian ATSB in a 2002 report noted pilot delay in using oxygen during a contaminated air event allowed the pilot to remain being, ‘exposed to potentially contaminated air, the PIC might have risked degradation of his faculties, which then may have reduced his ability to correctly determine if there was a flight hazard and respond appropriately.’ [6]
The Australian ATSB on commenting on cabin crew use of oxygen that, ‘The cabin crew oxygen is a, ‘diluter or therapeutic’ mask type. This design does not provide protection from smoke or fumes as most of the air mixture provided is ambient air. Under certain circumstances involving heavy contamination by fumes, the use of this type of mask might mislead the user into a false sense of protection and lead to the possibility of being overcome by the fumes. The limited protection afforded by this type of mask should be brought to the attention of cabin crew.’ [6]
By reviewing the UK contaminated air events database as well as other documentation describing events it is clear oxygen is rarely being used, despite the requirement to do so. This is the case whether the aircraft has the updated aircraft checklists or not, confirming again that education is vital to bring about change. Some of the events reporting oxygen is not being used state:
2002. B757: ‘… ongoing problem on this fleet re oily smells in the flight deck … Crew did not use 02 as advised by airline this meant declaring emergency and felt best not to do unless really violent effects from the smoke and used to bad smells on aircraft… P1 advised smelt perhaps 100 times on aircraft…’
2004. BAe 146: CAA MOR number 200402057. ‘Mayday declared on descent into Paris as thick blue smoke filled the cabin - Oxygen not used… Capt could barely detect smell or smoke and decided oxygen not required for crew or passengers…’
2005. A320: ‘Strong smell of 'oily mist' experienced on flight deck during Climb and descent… Flight continued to destination, no Oxygen used by flight crew… We do not have any guidance from (airline) on this issue... It would be nice to have an update to our SOPs from (airline), so that we don't feel 'pressured' to continue the flight… It’s a difficult call to make during a flight to don oxy masks and divert, just for a 'smell'!! (unless that’s what (airline) recommends).’
2005. B757: ‘Strong oil fumes … Oxygen not used as aircraft had a long history over several months and assumed must be safe or aircraft would not be flying… Unaware of need to use oxygen in all cases of contamination or suspected contamination…’
British Aerospace like the CAA advised in 2000 that with regard to emergency use of oxygen by the pilots, ‘An integral part of the way we design the aircraft and the way in which the operating drills are written is that oxygen masks are there for these kinds of circumstances and they should be used.’ [17]
Contaminated air event data clearly shows oxygen is rarely being used today, is ineffective for the cabin crew and non existent for the passengers. The BAe 146 checklist never advised its crews to use oxygen during fume events until 2001. The 1990 checklist advised oxygen was to be used during smoke and fire with the checklist only changing in 2001 (see All Operator Message Ref 01/004V). [29]
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
Aviation Regulators Misinterpret Main Ventilation Airworthiness / Safety Standard
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References
6. ATSB Report: Occurrence Brief 200205307. 11 January, 2002. Aircraft Registration: VH-NJD - BAe 146.
17. British Aerospace (2000) Hansard Evidence by British Aerospace to the Australian Senate inquiry into air safety (1999–2000) BAe 146 cabin air quality. Parliament of Australia, Canberra.
29. BAe (1990) BAe 146 Manufacturer’s Operations Manual: Emergency and Abnormal Procedures Check List/Smoke or Fire Protection. British Aerospace Systems, Hatfield.
101. UK House of Lords written question. Countess of Mar. [HL1763] 1November 2005.
109. UK House of Commons written question. Tyler P. MP [[202745], 7 December, 2004.
