Summary
This document proposes to supersede Airworthiness Directive (AD) 80-22-04, which currently requires the following on The New Piper Aircraft, Inc. (Piper) Models PA31, PA31-300, PA31-325, and PA31-350 airplanes: Repetitively inspecting the upper section of Fuselage Station (FS) 317.75 bulkhead for cracks, and incorporating a certain reinforcement kit if any crack is found. The proposed action would require inspecting (one-time) the upper section of the FS 317.75 bulkhead for cracks, and incorporating one of two reinforcement kits depending on whether cracks are found in the FS 317.75 bulkhead area. Cracks found on airplanes in compliance with the inspection requirements of AD 80-22-04 and the Federal Aviation Administration's policy on aging commuter-class aircraft prompted the proposed action. The actions specified in the proposed AD are intended to prevent structural failure of the vertical fin forward spar caused by cracks in the FS 317.75 bulkhead, which, if not detected and corrected, could result in loss of control of the airplane.