Action
Final rule; request for comments.
Summary
We are adopting a new airworthiness directive (AD) for all CFM International S.A. (CFM) Model CFM56-7B engines. This AD requires initial and repetitive inspections of the concave and convex sides of the fan blade dovetail to detect cracking and replacement of any blades found cracked. This AD was prompted by a recent engine failure due to a fractured fan blade, that 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.