Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to AlliedSignal Inc. (formerly Textron Lycoming) T5311, T5313, T5317, and T53 series military engines approved for installation on aircraft certified in accordance with Section 21.25 of the Federal Aviation Regulations (FAR). This proposal would require removal and replacement of the N2 spur gear nut retainer (lock cup). This proposal is prompted by reports of N2 spur gear nut retainer (lock cup) separation. The actions specified by the proposed AD are intended to prevent N2 accessory drive assembly disengagement due to N2 spur gear nut retainer (lock cup) separation, which could result in an uncommanded engine acceleration.