Final rule · 2025-03395

Airworthiness Directives; The Boeing Company Airplanes

The FAA is adopting a new airworthiness directive (AD) for all The Boeing Company Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes. This 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 AD requires replacing the fasteners on the fan cowl support beam hinge fittings for certain airplanes and, for all airplanes, requires modifying the radial restraint assembly and installing an external doubler at the starter vent, or as an option, installing a serviceable fan cowl. This AD also requires revising the existing maintenance or inspection program, as applicable, to incorporate new airworthiness limitations. The FAA is issuing this AD to address the unsafe condition on these products.