Airworthiness Directives; Jetstream Aircraft Limited HP137 Mk1, Jetstream Series 200, and Jetstream Models 3101 and 3201 Airplanes

요약

This document proposes to supersede Airworthiness Directive (AD) 81-20-01, which currently requires repetitively inspecting the nose landing gear (NLG) actuator support structure and the front pressure bulkhead for cracks on Jetstream Aircraft Limited (JAL) HP137 Mk1 and Jetstream series 200 airplanes, and replacing any cracked part. The proposed action would: retain the repetitive inspections required by AD 81-20-01; require repetitively inspecting the NLG retraction jack upper mounting fitting and attachment hardware for security bolt failure and for bolts with improper torque levels on the HP137 Mk1, Jetstream series 200, and Jetstream Model 3101 airplanes, and require replacing any failed security bolts and adjusting any bolt with an improper torque level; and require modifying the NLG retraction jack on all affected airplanes as terminating action for the repetitive inspections. The proposed action is prompted by reports of NLG jack mounting fitting failures on several of the affected airplanes, and by the Federal Aviation Administration's policy on aging commuter-class aircraft. The actions specified in the proposed AD are intended to prevent failure of the NLG caused by a cr