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Interim Recommendation issued to: Federal Aviation Administration (FAA)

Recommendation details
Output No: IR19990152
Date issued: 07 October 1999
Safety action status:
Background: Why this Interim Recommendation was developed

Output text

The Bureau of Air Safety Investigation recommends that the Federal Aviation Administration reassess the appropriateness of the current maintenance procedures for the testing of automatically deployable passenger oxygen systems and cabin altitude alert systems, to ensure complete system operation.

As a result of the investigation into this safety deficiency, the Bureau simultaneously issues the following interim recommendations:

IR19990150

The Bureau of Air Safety Investigation recommends that Raytheon Aircraft develop and publish methods for the in-situ testing of the automatically deployable passenger oxygen activation system and the cabin altitude alert system on Beechcraft aircraft, to ensure complete system operation.

IR19990151

The Bureau of Air Safety Investigation recommends that the Civil Aviation Safety Authority reassess the appropriateness of the current maintenance procedures for the testing of automatically deployable passenger oxygen systems and cabin altitude alert systems, to ensure complete system operation.

IR19990153

The Bureau of Air Safety Investigation recommends that Raytheon Aircraft consider the incorporation of an audible warning to operate in conjunction with the cabin altitude alert system on all Beech aircraft so equipped.

IR19990154

The Bureau of Air Safety Investigation recommends that the Civil Aviation Safety Authority consider the incorporation of an audible warning to operate in conjunction with the cabin altitude alert system on Beech aircraft, and other aircraft so equipped.

IR19990155

The Bureau of Air Safety Investigation recommends that the Federal Aviation Administration consider the incorporation of an audible warning to operate in conjunction with the cabin altitude alert system on Beech aircraft, and other aircraft so equipped.

Initial response
Date issued: 31 March 2000
Response from: Federal Aviation Administration (FAA)
Action status: Closed - Accepted
Response text:

The Office of Accident Investigation convened a Safety Recommendation Review Board to review the enclosed responses to your safety recommendations. As a result, the Review Board classified your recommendations as follows:

(*IR19990152) 99.400 - "Closed - Acceptable Action"

This is in response to Safety Recommendation[s] 99.400, which pertain[s] to passenger oxygen systems and cabin altitude alert systems on Raytheon Model 200 Series aircraft. Safety Recommendation 99.400 requested a review of the appropriateness of the current maintenance procedures for the testing of automatically deployable passenger oxygen systems and cabin altitude alert systems to ensure complete system operation.

In assessing Safety Recommendation 99.400, the B200 Maintenance Manual procedures for functional testing of the oxygen auto-deploy system and the cabin altitude alert system were reviewed. The procedures were found to be acceptable with the exception of functional testing of the two barometric pressure switches (one for the oxygen system and one for the annunciator system) installed in the airplane. There is currently no provision to functionally cheek the operation of either switch to ensure that it would provide the required signal at the specified cabin altitude of 12,500 feet. To address this issue, Raytheon Aircraft Company has agreed to revise the affected maintenance manuals to add a procedure to functionally check both barometric pressure switches referred to above.

In conclusion, this office considers the actions identified in this letter to be satisfactory in addressing the safety concern. Raytheon Aircraft Company has committed to making the necessary changes to the maintenance manuals of the affected airplanes to verify that the barometric pressure switches will actuate at the required altitude.

Therefore, the Wichita ACO recommends that Safety Recommendations 99.400 be closed.

 
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Last update 01 April 2011