Airworthiness Directives; Honeywell International Inc. TFE731-2, -3, and -4 Series Turbofan Engines

This amendment supersedes two existing airworthiness directives (ADs), applicable to Honeywell International Inc. (formerly AlliedSignal Inc. and Garrett Turbine Engine Co.) TFE731-2, -3, and -4 series turbofan engines. Those AD's currently require removing certain fan rotor discs from service in accordance with a drawdown schedule, and establishing new fan rotor disc life limits. This amendment requires stricter life limits for certain fan rotor discs. This amendment is prompted by the availability of an improved fan rotor disc and by a reduction in the probability of fan rotor disc failure by terminating the life of the older, high-stressed, fan rotor disc. The actions specified in this AD are intended to prevent failure of the fan rotor disc due to fatigue cracking in the dovetail slots, which could result in in-flight engine shutdown, uncontained engine failure, and damage to the airplane.