Action
Final rule; request for comments.
Summary
We are superseding Airworthiness Directive (AD) 2016-13-10, for certain The Boeing Company Model 737-300, -400, and -500 series airplanes. AD 2016-13-10 required repetitive external detailed inspections and nondestructive inspections to detect cracks in the fuselage skin along the chem-mill steps at stringers S-1 and S-2R, between station (STA) 400 and STA 460, and repair if necessary. AD 2016-13-10 also required a preventive modification of the fuselage skin at crown stringers S-1 and S-2R. This AD requires the same actions as AD 2016-13-10, and clarifies certain regulatory text. This AD was prompted by the determination that certain regulatory text in AD 2016- 13-10 requires clarification. We are issuing this AD to detect and correct fatigue cracking of the fuselage skin panels at the chem-mill steps, which could result in sudden fracture and failure of the fuselage skin panels, and consequent rapid decompression of the airplane.