AD FAA-2018-0429

We are adopting a new airworthiness directive (AD) for CFM International, S.A., (CFM) CFM56-7B model engines. This emergency AD was sent previously to all known U.S. owners and operators of CFM CFM56-7B model engines. This AD requires a one-time ultrasonic inspection (USI) of the concave and convex sides of the fan blade dovetail. This AD was prompted by a recent engine failure due to a fractured fan blade, which resulted in the engine inlet cowl disintegrating and debris penetrating the fuselage, causing a loss of pressurization, and prompting an emergency descent. We are issuing this AD to address the unsafe condition on these products.