FAA has issued an Airworthiness Directive, ordering operators of certain Model 767-300 and -300F series airplanes to conduct checks on the wing structure following reports of fatigue cracking on airplanes with winglets installed.
Boeing launched certain models of 767-300 with winglets in 2007 and, later many airlines including American, Delta and United modified their planes and installed winglets.
FAA directive requires high frequency eddy current (HFEC) inspections for cracking of the lower outboard wing skin, and repair or modification if necessary.
The AD also requires one of three follow-on actions: Repeating the HFEC inspections, modifying certain internal stringers and oversizing and plugging the existing fastener holes of the lower wing, or modifying the external doubler/tripler and doing repetitive post-modification inspections.
According to FAA, this AD affects 140 airplanes of U.S. registry and would cost $71,400 for carrying out inspection and estimated Costs–On-Condition Actions would be $22,270.
Effective Date of the AD is July 10, 2018.