Contaminated Air Service Bulletin

Source: Aviation Contaminated Air Reference Manual

Service Bulletin 21-156 ©	10th April 2008
by Susan Michaelis

On 31 October 2002, British Aerospace BAe 146 issued another Service Bulletin (SB) numbered: ISB.21-156. This was intended to complement the previous service bulletin raised in 2001 by British Aerospace that the Australian and UK regulators made mandatory as Airworthiness Directives. The statement that fumes had been seen as a nuisance in the past and must for the time being be seen as a potential threat to flight safety was repeated. The relevant extracts are shown below. The service bulletin was titled, ‘To inspect air conditioning sound-attenuating ducts for signs of oil contamination.’

British Aerospace BAe 146
Service Bulletin ISB 21-156
Date: 20 March 2001

Title: AIR CONDITIONING - TO INSPECT AIR CONDITIONING SOUND-ATTENUATING DUCTS FOR SIGNS OF OIL CONTAMINATION.

Reason: …In the past, oil leaks and cabin / flight deck odours and fumes may have come to be regarded as a nuisance rather than a potential flight safety issue…

…oil leaks and cabin / flight deck odours must be regarded as a potential threat to flight safety, they should not be dismissed as a mere nuisance and should be addressed as soon as possible.

Mandatory Inspection Bulletin ISB 21-150 was issued in April 2001 to inspect the engine oil seals, the APU and the ECS jet pumps and air conditioning packs for signs of oil contamination. Following further investigations of cabin air quality complaints by BAE SYSTEMS, this ISB is intended to supplement the ISB.21-150 by extending the areas inspected to include the sound attenuating ducting downstream of the packs under the rear cabin floor, either side of the mixing chamber duct/filter housing. It has been shown by recent inspection of in-service aircraft that sound attenuating material within these ducts has acted as an absorbent for oil contamination on some aircraft.

This ISB does not replace ISB.21-150, it must be complied with in addition to ISB.21-150.

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Flight Safety Aspects of Contaminated Air

• Emergency Checklists and Initial Crew Responses

• Defect Reporting

• Reporting Contaminated Air Events with Samples of Known Events

• Aviation Industry Could Have Acted

• Definition of Safety

• FODCOM (Flight Operations Department Communication) number 17/2000

• All Operators Message Ref 00/030V and Ref 01/004V

• Service Bulletin ISB 21-150

• Airworthiness Directive AD 002-03-2001

• When Change was Needed it did Not Occur

• FODCOM (Flight Operations Department Communication) number 14/2001 and 21/2002

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