Airworthiness Directives; Jetstream Aircraft Limited Model 3201 Airplanes

This amendment adopts a new airworthiness directive (AD) that applies to Jetstream Aircraft Limited (JAL) Model 3201 airplanes. This action requires repetitively inspecting the main landing gear (MLG) bay forward lower edge wing skin structure for cracks, replacing any cracked doubler with a joggled doubler of improved design to reinforce the area and prevent future cracking, and eventually incorporating these doublers on all affected airplanes. Cracking found at the MLG bay forward lower edge wing skin structure during fatigue testing of the JAL Model 3201 prompted this action. The actions specified by this AD are intended to prevent the MLG bay forward lower edge wing skin structure from cracking, which, if not detected and corrected, could cause failure of the wing structure and loss of control of the airplane.