Summary
This document proposes to adopt a new airworthiness directive (AD) that would apply to certain Jetstream Aircraft Limited (JAL) Model 3201 airplanes. The proposed action would require 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 airplanes prompted the proposed action. The actions specified by the proposed 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.