FAA mandates Ultrasonic Inspection on all GE GEnx Engines

National aviation authority of the United States, Federal Aviation Administration(FAA) has issued Airworthiness Directive (AD) 2012-19-08, w...

National aviation authority of the United States, Federal Aviation Administration(FAA) has issued Airworthiness Directive (AD) 2012-19-08, which requires that all GEnx engines undergo ultrasonic inspection of the Fan Mid-Shaft(FMS) before further flight. The AD also establishes that the FMS be subject to recurring inspections that must be accomplished not more than 90 days between inspections.
According to Boeing and GE, the immediate initial inspections on all affected engines in-service were completed as of September 19, 2012.
The directive comes after an “urgent recommendation” from the U.S. National Transportation Safety Board (NTSB) for immediate and repetitive inspections on the GE GEnx engine family, which powers the Boeing 787 and 747-8.
The NTSB request followed an initial investigation into a contained GEnx-1B engine failure on a 787 while in ground testing in July at Boeing’s final assembly facility in Charleston, S.C.
The failure involved cracks in the fan mid-shafts (FMS) of the engine’s low-pressure turbine. An inspection of a second GEnx-1B on-wing in August also showed FMS crack.
Engine maker GE says it has introduced changes in the production process that “address environmentally assisted cracking, including changes to the dry-film coating applied to the mid-shaft at the manufacturing stage, as well as changes to the assembly lubricant used when the retaining nut is clamped to the mid-shaft.