Summary
This document proposes the adoption of a new airworthinessdirective (AD) that is applicable to AlliedSignal Inc. (formerly Garrett Engine Division) TFE731 series turbofan engines. This proposal would require removing certain fan rotor disks from service in accordance with a drawdown schedule, and would establish new fan rotor disk life limits. This proposal is prompted after additional analyses revealed that stress levels in the fan rotor disk dovetail slots for the applicable engine models are higher than initially calculated. The actions specified by the proposed AD are intended to prevent uncontained failure of the fan rotor disk due to fatigue cracking in the dovetail slots, which can result in inflight engine shutdowns, severe secondary damage, and fan rotor assembly separation from the engine.