AD 2006-21-09 Airworthiness Directives; Boeing Model 777-200 Series Airplanes Equipped with General Electric GE90-94B Engines

Models named: 777-200 series. Read the applicability below — it usually turns on serial or part numbers too.

This AD applies to Boeing Model 777-200 series airplanes equipped with General Electric GE90-94B engines; certificated in any category; as identified in Boeing Alert Service Bulletin 777-78A0056, dated April 20, 2006.

You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done. General Visual Inspection/Investigative and Corrective Actions (f) Within 24 months after the effective date of this AD: Do a general visual inspection to determine the part number of the identification plate of the torque box on the TRs, and do all applicable investigative and corrective actions before further flight, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 777-78A0056, dated April 20, 2006. If any discrepancy is found and the service bulletin specifies to contact Boeing for appropriate action: Before further flight, repair the TR using a method approved in accordance with the procedures specified in paragraph (g) of this AD. Note 1: The Boeing service bulletin refers to Spirit AeroSystems Document MAA7-70023-1, dated November 22, 2005, as an additional source of service information for accomplishing the corrective actions. Alternative Methods of Compliance (AMOCs) (g)(1) The Manager, Seattle Aircraft Certification Office (ACO), FAA, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19. (2) Before using any AMOC approved in accordance with § 39.19 on any airplane to which the AMOC applies, notify the appropriate principal inspector in the FAA Flight Standards Certificate Holding District Office. (3) An AMOC that provides an acceptable level of safety may be used for any repair required by this AD, if it is approved by an Authorized Representative for the Boeing Commercial Airplanes Delegation Option Authorization Organization who has been authorized by the Manager, Seattle ACO, to make those findings. For a repair method to be approved, the repair must meet the certification basis of the airplane. Material Incorporated by Reference (h) You must use Boeing Alert Service Bulletin 777-78A0056, dated April 20, 2006, to perform the actions that are required by this AD, unless the AD specifies otherwise. The Director of the Federal Register approved the incorporation by reference of this document in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207, for a copy of this service information. You may review copies at the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street, SW., Room PL-401, Nassif Building, Washington, DC; on the Internet at http://dms.dot.gov; or at the National Archives and Records Administration (NARA). For information on the availability of this material at the NARA, call (202) 741-6030, or go to http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html. Issued in Renton, Washington, on October 10, 2006. Kalene C. Yanamura, Acting Manager, Transport Airplane Directorate; Aircraft Certification Service. [FR Doc. E6-17428 Filed 10-18-06; 8:45 am] BILLING CODE 4910-13-P

This AD results from engine certification testing which revealed that thrust reversers (TRs) on GE90-94B engines have inner walls that could develop disbonding in the upper bifurcation radii. Disbonding was found in an equivalent inner wall used during the testing. We are issuing this AD to prevent failure of a TR and adjacent components and their consequent separation from the airplane during flight or during a refused takeoff (RTO). These separated components could cause structural damage to the airplane or damage to other airplanes and possible injury to people on the ground. TR failure during a RTO could also cause the engine to produce forward thrust, resulting in asymmetric thrust and possible runway excursion.