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Recommendation issued to: British Aerospace Plc

Recommendation details
Output No: R19990053
Date issued: 06 September 1999
Safety action status:
Background: Why this Recommendation was developed

Output text

The Bureau of Air Safety Investigation recommends that British Aerospace Plc liaise with the engine manufacturer, AlliedSignal, to investigate failures within the engine that result in fumes entering the cockpit and cabin areas of BAe146 aircraft.

As a result of the investigation of this occurrence, the Bureau simultaneously issues recommendation R990052 to the Civil Aviation Safety Authority:

"The Bureau of Air Safety Investigation recommends that the Civil Aviation Safety Authority, in conjunction with the aircraft manufacturer, British Aerospace Plc, address deficiencies that permit the entry of fumes into the cockpit and cabin areas of BAe146 aircraft. These deficiencies should be examined by the regulatory authority as part of its' responsibilities for initial certification and continued airworthiness of the BAe 146 Aircraft".

Initial response
Date issued: 14 March 2000
Response from: British Aerospace Plc
Action status: Closed - Partially Accepted
Response text:

I am in receipt of the second draft of the above report, made available to me on 24 August. Whilst we are grateful for the opportunity to make verbal comments to you, we are dismayed at the time made available to us to do so, (i.e. by 9am Thursday August 25), especially given the time differences existing between me and my colleagues in the United Kingdom. Given the importance of the matter, I have set out below the substance of those comments, which in the time available, we have formulated:

1. Bae's Previous comments

1.1 As you are aware, BAe submitted a detailed response to the first draft of the report on 22 July 1999. Despite various requests, we were not afforded the opportunity to discuss our submission or the Report with you or any members of your team in person. Given the nature of the Report and its recommendations, we were surprised at this lack of consultation.

1.2 Similarly, we are also disappointed to note that the second draft fails to take into account or address the majority of our comments. In particular, it fails to answer the majority of the points we raised in paragraphs 1, relating to flight crew procedure, and 2, maintenance procedures, and why those procedures were not followed.

1.3 According to the Report, the cause of the incident was oil contamination of the air supply, (although there is no evidence of the investigative basis for this finding). BAe accepts that from time to time oil may leak into the air system. However, as we have previously advised, when it became evident that this was occurring, BAe in conjunction with Allied Signal in between 1991 and 1992, developed modifications to reduce the frequency of such leaks. A customer option of an oil filtration system was also introduced. No mention is made of such modifications in your Report, or even whether the aircraft in question was fitted with them. Given such modifications, we consider that the safety recommendations in your Report have already been complied with.

1.4 In any event, on the basis of the circumstances described in the Report, the sole reason why this incident occurred is because maintenance and operating procedures set out in the relevant MEL were not followed. Had the defective air supply been correctly labelled and isolated, the alleged oil contamination would not have occurred (as is demonstrated by the fact that when the flight continued the scheduled sectors with the number 4-engine bleed air system turned off, these were completed without incident). Further, the aircraft appears to have been operated for more than the ten-day period set out (recommended) in the MEL. Given these facts, we are surprised that these matters are not referred to in the Report.

1.5 Similarly, basic aircrewmanship dictates that in this type of situation oxygen masks should have been immediately donned. If this had been the case, the affected crewmembers would not have been prevented from properly carrying out their assigned duties, and hence there should have been no threat to air safety. We do not consider the comment "the crew did not consider the use of oxygen masks necessary in the situation", to be an adequate explanation of why this was not done.

2. Anecdotal Evidence

2.1 Much of the report relates to purely anecdotal evidence of other incidents. You seek to link these with the incident under investigation. While the nature of the Report makes it impossible for us to comment on or assess the further incidents referred to, it is our firm view that recent complaints regarding cabin air quality arise from circumstances largely unconnected to oil contamination and are not therefore relevant to the incident under investigation. Yet, not only does *the Report refer extensively to this anecdotal evidence, it fails to mention the additional customer optional modifications that BAe has recently developed in conjunction with Ansett Australia to address cabin air quality issues and which are currently being embodied on Ansett's fleet.

3. Failure to ICAO Practices

We have expressed our disappointment at your refusal to have a meeting with us to discuss this Report. We also understand that you failed to follow ICAO guidelines as set out in Annex 13, in that you failed to follow standard reporting layout and that you made no format notification to the UK Air Investigation Board. We understand that the AA1B have made separate representations to you to that effect. We also are led to believe that, at no stage, did you contact UK Civil Aviation Authority, the Design Authority for the aircraft.

4. Conclusion

In summary, our position remains that we continue to disagree with the substance or your Report. We again request the opportunity to meet with you and your team to go through the Report in detail.

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Last update 01 April 2011