Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to AlliedSignal Inc. TFE731 series turbofan engines. This proposal would require removal from service of certain low pressure turbine (LPT) seal plates prior to accumulating the new, reduced cyclic life limit, and replacement with serviceable LPT seal plates. This proposal is prompted by a report that the machined LPT seal plate geometry did not meet the design intent due to drawing ambiguity. The actions specified by the proposed AD are intended to prevent fatigue cracking and subsequent uncontained failure of an LPT seal plate.