AD FAA-2013-0330

We are adopting a new airworthiness directive (AD) for certain Tracor (Convair) Model 340 and 440 airplanes and certain Military Model C-131B, C-131D, C-131E, and C131F/R4Y-1 airplanes. This AD requires repetitive inspections of the lower skin of the wings for cracking around the inboard side of the wing station (WS) 6 and 7 access panel doubler fingers and between stringers 5 and 11; repetitive inspections of the lower skin of the wings for cracking around stringers 6, 8, and 10, and around the WS 6 and WS 7 access panel doubler fingers; and repair if necessary. This AD was prompted by a report of a crack found on the lower skin of the right-hand wing between WS 5 and WS 6. We are issuing this AD to detect and correct fatigue cracking of the lower skin of the wings, which could result in reduced structural integrity of the wings.