Safety Recommendation a-12-052
Details
Synopsis: On July 28, 2012, a Boeing 787-8 airplane experienced a loss of thrust in the right engine—a General Electric (GE) GEnx-1B turbofan, engine serial number (ESN) 956-121—during a pre-first flight, low-speed taxi test at Charleston International Airport, Charleston, South Carolina.1 As the airplane was accelerating through 40 knots, the No. 2 engine’s N12 speed rolled back and the pilots retarded the throttles to abort the test. The airplane taxied back to the ramp, where the engines were shut down. A visual inspection of the engine during the NTSB’s investigation revealed the low pressure turbine (LPT) rotor had shifted aft and extensive damage to the LPT blades and vanes. Further examination of the engine revealed the forward end of the FMS was separated at the rear of the threads. The fractured end of the FMS with the retaining nut still in place was removed from the engine and sent to GE, Cincinnati, Ohio, for dimensional inspection and metallurgical examination. The engine was subsequently removed from the airplane and also sent to GE in Cincinnati for disassembly and examination. The engine had not yet been operated in flight, having only been operated during post-production tests at GE and post-installation ground runs at Boeing in Charleston.
Recommendation: TO THE FEDERAL AVIATION ADMINISTRATION: Issue an airworthiness directive to require, before further flight, the ultrasonic inspection of the fan midshaft in all General Electric GEnx-1B and -2B engines that have not yet undergone inspection. (A-12-52) (Urgent)
Original recommendation transmittal letter: PDF
Overall Status: Closed - Acceptable Action
Mode:
Location: Charleston, SC, United States
Is Reiterated: No
Is Hazmat: No
Is NPRM: No
Accident #: DCA12IA114
Accident Reports:
Report #: None
Accident Date: 7/28/2012
Issue Date: 9/14/2012
Date Closed: 1/31/2013
Addressee(s) and Addressee Status: FAA (Closed - Acceptable Action)
Keyword(s):

Safety Recommendation History
From: NTSB
To: FAA
Date: 1/31/2013
Response: 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.

From: FAA
To: NTSB
Date: 11/8/2012
Response: -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.