Airworthiness Directives; The Boeing Company Airplanes

We propose to adopt a new airworthiness directive (AD) for certain The Boeing Company Model 767-300 and -300F series airplanes. This proposed AD was prompted by reports of fatigue cracking on airplanes with Aviation Partners Boeing winglets installed. This proposed AD would require a high frequency eddy current (HFEC) inspection for cracking of the lower outboard wing skin, and repair or modification if necessary. This proposed AD would also require 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. We are proposing this AD to prevent fatigue cracking in the lower outboard wing skin, which could result in failure and subsequent separation of the wing and winglet and consequent reduced controllability of the airplane.