Airworthiness Directives; The Boeing Company Airplanes

The FAA proposes to supersede Airworthiness Directive (AD) 2018-11-14, which applies to certain The Boeing Company Model 767-300 and -300F series airplanes. AD 2018-11-14 requires high frequency eddy current (HFEC) inspections for cracking of the lower outboard wing skin, and repair or modification if necessary. AD 2018-11-14 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. Since the FAA issued AD 2018-11-14, it was determined that, for certain airplanes, the area of the lower wing skin in the vicinity of the critical inboard end fasteners of installed repair doublers must be inspected. In addition, it was determined that airplanes who have installed Supplemental Type Certificate (STC) ST01920SE and removed the STC winglets are also affected by the unsafe condition. This proposed AD would continue to require the actions in AD 2018-11-14, add airplanes to the applicability who have installed STC ST01920SE and removed the STC winglets, and, for certain airplanes, would require repetitive internal and external HFEC inspections of the lower outboard wing skin common to the external doubler repair at stringer L-9.5 and repair if necessary. The FAA is proposing this AD to address the unsafe condition on these products.