Airworthiness Directives; de Havilland Model DHC-7 Series Airplanes

This amendment adopts a new airworthiness directive (AD), applicable to all de Havilland Model DHC-7 series airplanes, that requires certain structural inspections, and repair, if necessary. This amendment is prompted by a structural re-evaluation, which identified certain significant structural items to inspect for fatigue cracking as these airplanes approach and exceed the manufacturer's original design life. The actions specified by this AD are intended to prevent fatigue cracking in these areas which, if not detected and corrected in a timely manner, could reduce the structural integrity of these airplanes.