Airworthiness Directives; The Boeing Company Airplanes

FAA / Federal Register · 2023-27100

The FAA proposes to adopt a new airworthiness directive (AD) for all The Boeing Company Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes. This proposed AD was prompted by two engine fan blade-out (FBO) events that resulted in the separation of engine inlet cowl and fan cowl parts from the airplane. In one event, fan cowl parts damaged the fuselage, which caused loss of pressurization and subsequent emergency descent. This proposed AD would require replacing the fasteners on the fan cowl support beam hinge fittings for certain airplanes and, for all airplanes, would require modifying the radial restraint assembly and installing an external doubler at the starter vent, or as an option, installing a serviceable fan cowl. This proposed AD would also require revising the existing maintenance or inspection program, as applicable, to incorporate new airworthiness limitations. The FAA is proposing this AD to address the unsafe condition on these products.