ADs Seek To Tame Engine, APU Problems
The FAA has adopted and/or proposed a series of Airworthiness Directives (ADs) that will affect operators of Honeywell ALF502/507 and TFE731 engines and Sundstrand APUs. ALF502L-2 and L-2C engine compressor discs may have had too much disc balance material removed, which could cause premature fracturing of the disc. The FAA has already issued this AD as a final rule (AD2009-08-07) effective May 18. ALF502/507s would be subject to a proposed AD offering replacement of affected cracked fuel manifolds as a terminating action to replace repetitive inspection intervals. Honeywell TFE731 turbofans with certain low-pressure compressor rotor discs may be subject to an AD. The proposed AD stems from reports of cracked disc bores, “which could result in an uncontained failure.” Sundstrand Power Systems T62T-46C12 APUs would require updated Fadec software under a proposed AD resulting from two APU-compartment explosions. These occurred during the start sequence and were caused by over-fueling of the APU at low rpm. Comments on all three proposed ADs are due by June 12.