AD 97-07-11 Amendment 39-9985

This amendment supersedes 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. This AD retains the repetitive inspections required by AD 81-20-01; requires 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 requires replacing any failed security bolts and adjusting any bolt with an improper torque level; and requires modifying the NLG retraction jack on all affected airplanes, as terminating action for the repetitive inspections. This AD results from reports of NLG jack mounting fitting failures on several of the affected airplanes, and the Federal Aviation Administration's policy on aging commuter-class aircraft. The actions specified by this AD are intended to prevent failure of the NLG caused by a cracked NLG actuator support structure or cracked front pressure bulkhead, which, if not detected and corrected, could lead to nose gear collapse and damage to the airplane.