Airworthiness Directives; Bombardier Model DHC-7-100 Series Airplanes

This amendment revises an existing airworthiness directive (AD), applicable to all Bombardier Model DHC-7-100 series airplanes, that currently requires repetitive high frequency eddy current inspections to detect cracks on the locking pin fittings of the baggage door and locking pin housings of the fuselage; repetitive detailed inspections to detect cracks of the inner door structure on all four door locking attachment fittings; and corrective actions if necessary. In lieu of accomplishing the corrective actions, that amendment also provides a temporary option, for certain cases, for revising the Airplane Flight Manual and installing a placard. That AD was prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by that AD are intended to detect and correct fatigue cracking of the baggage door fittings and the support structure, which could result in structural failure, and consequent rapid decompression of the airplane during flight. This amendment extends the compliance time of the repetitive inspections based on test evidence and is intended to address the identified unsafe condition.