Summary
The FAA proposes to adopt a new airworthiness directive (AD) for Rolls-Royce Corporation (formerly Allison Engine Company) AE 3007A1, AE 3007A1/1, AE 3007A1/3, AE 3007A3, AE 3007A1E, and AE 3007A1P turbofan engines, with 1st to 2nd stage turbine spacers, part number (P/N) 23069627, 23070989, 23072849, or 23075364 installed. This proposed AD would reduce the life limit for 1st to 2nd stage turbine spacer, part number (P/N) 23072849, to a certain lower life limit, based on engine model. This proposed AD would also require a one-time fluorescent penetrant inspection (FPI) of 1st to 2nd stage turbine spacers P/Ns 23069627, 23070989, 23072849, and 23075364 before reaching the spacer life limit, within specified cycles-since-new (CSN), and would require replacement of the spacer if found cracked, or with bent or missing aft tangs. This proposed AD is prompted by a report that during a scheduled inspection, aft pilot tangs on a 1st to 2nd stage turbine spacer were found bent and cracked. The actions specified in this proposed AD are intended to prevent 1st to 2nd stage turbine spacer failure, leading to uncontained turbine failure, engine shutdown, and damage to the airplane.