Aviation safety issues and actions
Interim Recommendation issued to: Allied Signal Aerospace
|Date issued:||13 August 1999|
|Safety action status:|
|Background:||Why this Interim Recommendation was developed|
The Bureau of Air Safety Investigation recommends that the
engine manufacturer AlliedSignal determine the sensitivity of
turbine wheel seals to the initiation of fatigue cracks from slot
corners, as a function of slot corner radii.
As a result of investigation into this occurrence, the Bureau simultaneously issues the following interim recommendations and safety advisory notice:
The Bureau of Air Safety Investigation recommends that the engine manufacturer AlliedSignal audit the process employed to manufacture TPE 331 turbine wheel knife-edged seals to determine those factors that may lead to excessive variations in slot corner radii.
The Bureau of Air Safety Investigation recommends that the engine manufacturer AlliedSignal consider, during engine design and the formulation of continuing airworthiness instructions, the possibility that turbine wheel seal fatigue failure may result in hazardous modes of engine failure.
The Bureau of Air Safety Investigation recommends that the Civil Aviation Safety Authority Australia conduct an audit of that part of the aviation safety system that establishes the operational history of life-limited components, to establish why the operational history of second-stage turbine wheel, p/n 868272-1, s/n P03214C, could not be determined with certainty.
The Federal Aviation Administration should note the safety deficiency identified in this document and take appropriate action as considered necessary.
|Date issued:||21 October 1999|
|Response from:||Allied Signal Aerospace|
|Action status:||Closed - Accepted|
Please find attached AlliedSignal's planned actions and
AlliedSignal's Materials Analysis (MA) of the 2nd stage turbine
wheel from the subject incident.