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From:
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NTSB
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To:
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FAA
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Date:
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1/31/2013
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Response:
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On September 21, 2012, the FAA published AD 2012-19-08 as an immediate requirement. The AD, which applies to all GEnx-1B and GEnx-2B engines with certain FMS part numbers installed, requires an initial ultrasonic inspection (UI) of the FMS before further flight and repetitive UI of the FMS within every 90 days since the last inspection. Issuance of the AD fully satisfies Safety Recommendations A-12-52 and -53; accordingly, they are classified CLOSED—ACCEPTABLE ACTION.
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From:
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FAA
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To:
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NTSB
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Date:
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11/8/2012
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Response:
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-Michael P. Huerta, Acting Administrator: To address the safety issues identified in these recommendations, the Federal Aviation Administration (FAA) published the General Electric Company Turbofan Engines Airworthiness Directive (AD) Final Rule on September 21 , 2012 (77 FR 58471). This AD requires an initial ultrasonic inspection (UI) of the FMS before further flight and repetitive UI of the FMS within every 90 days since last inspection. This AD applies to all GE GEnx- l Band GEnx-2B engines with certain FMS part numbers installed. The affected FMS part numbers are susceptible to cracking and subsequent failure. The 90-day inspection interval is based on the crack propagation analysis performed by GE on the reported FMS failure and the report of a crack found in another FMS. The interval allows operators multiple opportunities to detect a crack before it reaches critical length and causes the FMS to fail. The FAA notes that this AD became effective on September 21, 2012, but we did provide the opportunity to submit comments by October 22, 2012. Based on the three comments that we received, we do not expect to revise the AD.
In the Board's September 14, 2012, letter, it stated that the damage noted on the photographs of the GEnx-2B engines that failed on September 11. 2012, in Shanghai, China, was consistent with that observed on the GEnx-l B engine that failed on July 28, 2012, in Charleston, South Carolina. However, preliminary inspections determined that the September 11 failure of the GEnx-2B engine was not the result of the FMS fracture. The FMS was later ultrasonically inspected and no fractures or cracks were found. Moreover, no axial shift in the LPT rotor was observed.
I believe the FAA has effectively addressed these safety recommendations and consider our actions complete.
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