AD 2008-23-10 Airworthiness Directives; Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D, 747-400F, and 747SR Series Airplanes

Models named: 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D, 747-400F. Read the applicability below — it usually turns on serial or part numbers too.

This AD applies to Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D, 747-400F, and 747SR series airplanes, certificated in any category; as identified in Boeing Service Bulletins 747-27A2398, Revision 1, dated July 31, 2008; and 747-27A2421, Revision 1, dated July 10, 2008.

You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done. Modification (f) Do the following, as applicable: At the time specified in paragraph 1.E. of Boeing Service Bulletins 747-27A2398, Revision 1, dated July 31, 2008; and 747-27A2421, Revision 1, dated July 10, 2008; except as provided by paragraph (g) of this AD, modify the outboard flap track and transmission attachments by doing all actions specified in the Accomplishment Instructions of the service bulletin. (g) Where Boeing Service Bulletins 747-27A2398, Revision 1, dated July 31, 2008; and 747-27A2421, Revision 1, dated July 10, 2008; specify compliance times relative to the date on the service bulletin, this AD requires compliance within the specified compliance time after the effective date of this AD. Credit for Actions Done According to Previous Issue of Service Bulletins (h) Actions done before the effective date of this AD in accordance with Boeing Alert Service Bulletins 747-27A2421 and 747-27A2398, both dated April 19, 2007, are acceptable for compliance with the requirements of paragraph (f) of this AD. Terminating Action for Certain Requirements of AD 2001-03-10 (i) Accomplishment of the modification specified in paragraph (f) of this AD terminates the requirements of paragraphs (a) and (b) of AD 2001-03-10, amendment 39-12114. Parts Installation (j) After completing the modifications required by paragraph (f) of this AD, no person may install a part identified in Table 1 of this AD on the modified airplane. Table 1—Parts Prohibited From Installation Part Part No. Hinge brace assembly for Tracks 1 and 8 65B15515-1   65B15515-2   65B15515-9   65B15515-10 Hinge brace assembly for Tracks 2 and 7 65B15525-1   65B15525-2   65B15525-7   65B15525-8   65B17092-1   65B17092-2 Support housing assembly for Tracks 1 and 8 65B81982-( ) Support housing assembly for Tracks 2 and 7 65B81950-( ) Alternative Methods of Compliance (AMOCs) (k)(1) The Manager, Seattle Aircraft Certification Office (ACO), FAA, ATTN: Doug Tsuji, Aerospace Engineer, Systems and Equipment Branch, ANM-130S; telephone (425) 917-6487; fax (425) 917-6590; has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. (2) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Before using any approved AMOC on any airplane to which the AMOC applies, notify your appropriate principal inspector (PI) in the FAA Flight Standards District Office (FSDO), or lacking a PI, your local FSDO. Material Incorporated by Reference (l) You must use Boeing Service Bulletin 747-27A2398, Revision 1, dated July 31, 2008; or Boeing Service Bulletin 747-27A2421, Revision 1, dated July 10, 2008; as applicable; to do the actions required by this AD, unless the AD specifies otherwise. (1) The Director of the Federal Register approved the incorporation by reference of this service information under 5 U.S.C. 552(a) and 1 CFR part 51. (2) For service information identified in this AD, contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207; telephone 206-544-9990; fax 206-766-5682; e-mail DDCS@boeing.com; Internet https://www.myboeingfleet.com. (3) You may review copies of the service information incorporated by reference at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the National Archives and Records Administration (NARA). For information on the availability of this material at 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 23, 2008. Ali Bahrami, Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. E8-26480 Filed 11-14-08; 8:45 am] BILLING CODE 4910-13-P

This AD results from a joint Boeing and FAA multi-model study (following in-service trailing edge flap structure and drive system events) on the hazards posed by skewing and failed flaps. This study identified the safety concerns regarding the transmission attachment design and the potential loss of an outboard trailing edge flap. We are issuing this AD to prevent certain discrepancies associated with this design (for example, a flap skew or lateral control asymmetry that can cause collateral damage to adjacent hydraulic tubing and subsequent loss of a hydraulic system), which could result in the asymmetric flight control limits being exceeded, and could adversely affect the airplane's continued safe flight and landing.