AD 2006-07-21 Airworthiness Directives; Boeing Model 757 Airplanes Powered by Pratt & Whitney Engines

Models named: 757-200, -200PF. Read the applicability below — it usually turns on serial or part numbers too.

This AD applies to Boeing Model 757-200, and -200PF airplanes, certificated in any category; having line numbers 1 through 639 inclusive; powered by Pratt & Whitney engines.

You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done. Inspections for Group 1 Airplanes (f) For airplanes identified as Group 1 in Boeing Service Bulletin 757-54-0042, Revision 1, dated July 7, 2005—which is referred to after this paragraph as “the service bulletin”: Within 18 months after the effective date of this AD, do general visual and detailed inspections for evidence of corrosion and/or cracking of the midspar fittings located in the nacelle struts, in accordance with the Accomplishment Instructions of the service bulletin. Repeat the inspections thereafter at intervals not to exceed 18 months until the requirements of paragraph (l) of this AD are accomplished. Note 1: For the purposes of this AD, a general visual inspection is defined as: “A visual examination of an interior or exterior area, installation, or assembly to detect obvious damage, failure, or irregularity. This level of inspection is made from within touching distance unless otherwise specified. A mirror may be necessary to ensure visual access to all exposed surfaces in the inspection area. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight, or droplight and may require removal or opening of access panels or doors. Stands, ladders, or platforms may be required to gain proximity to the area being checked.” Note 2: For the purposes of this AD, a detailed inspection is: “An intensive examination of a specific item, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate. Inspection aids such as mirror, magnifying lenses, etc., may be necessary. Surface cleaning and elaborate procedures may be required.” Inspections for Group 2 Airplanes (g) For airplanes identified as Group 2 in the service bulletin: Within 18 months after the effective date of this AD, identify the type of material used to make the midspar fittings, in accordance with Figure 4 of the Accomplishment Instructions of the service bulletin. (1) If all four midspar fittings are made of 15-5PH CRES material, no further action is required by this AD. (2) If any midspar fitting is made of 4330M material, do the inspections required by paragraph (h) of this AD. (h) For Group 2 airplanes with any fittings made of 4330M material: After identifying the fitting material as required by paragraph (g) of this AD, but before further flight: Do a general visual inspection and a detailed inspection of the 4330M midspar fittings for evidence of corrosion and/or cracking, in accordance with the Accomplishment Instructions of the service bulletin. Repeat the inspections for corrosion and/or cracking thereafter at intervals not to exceed 18 months until the requirements of paragraph (l) of this AD are accomplished. Cracking or Corrosion (i) For Group 1 and Group 2 airplanes: If any evidence of corrosion or cracking is found during any action required by paragraph (f) or (h) of this AD, before further flight, perform the corrective actions of paragraph (j) of this AD or the optional investigative actions of paragraph (k) of this AD. Corrective Actions (j) Replace the affected midspar fitting with a new midspar fitting by accomplishing all of the applicable actions in accordance with the Accomplishment Instructions of the service bulletin. Replacement of an affected midspar fitting terminates the repetitive inspections required by paragraphs (f) and (h) of this AD for that fitting only. Optional Investigative Actions (k) Perform one-time high-frequency eddy current (HFEC) and borescope inspections of any cracked or corroded bolt hole; and, before further flight, perform the applicable actions of paragraph (k)(1) or (k)(2) of this AD; in accordance with the Accomplishment Instructions of the service bulletin. (1) Repair corrosion damage or cracking of any bolt hole as specified in Figure 6 of the Accomplishment Instructions of the service bulletin; then accomplish paragraph (k)(1)(i) or (k)(1)(ii) of this AD as applicable. (i) Perform repetitive detailed inspections of any repaired bolt hole in accordance with Figure 7 of the service bulletin, at intervals not to exceed 300 flight cycles or 75 days, whichever occurs first, until the fitting is replaced as specified in paragraph (l) of this AD. Replace the repaired fitting with a new, improved fitting no later than 18 months after the repair of the bolt hole, or prior to further flight if any further evidence of corrosion or cracking is found in that fitting during any inspection required by this paragraph. Replacement of any fitting terminates the inspections required by paragraphs (f), (h), and (k)(1)(i) of this AD for that fitting only. (ii) Replace the midspar fitting with a new, improved fitting, in accordance with paragraph (j) of this AD. Replacement of any fitting terminates the inspections required by paragraph (f), (h), and (k)(1)(i) of this AD for that fitting only. (2) If any corrosion damage or cracking found during any inspection required by this AD cannot be repaired in accordance with paragraph (k)(1) of this AD, and the service bulletin specifies to contact Boeing for appropriate action, before further flight, perform the actions in paragraph (k)(2)(i) or (k)(2)(ii) of this AD, as applicable. (i) Repair the corrosion damage or cracking using a method approved in accordance with the procedures specified in paragraph (o) of this AD. (ii) Replace the midspar fitting with a new, improved fitting, in accordance with paragraph (l) of this AD. Optional Terminating Action (l) Replacement of all of the midspar fittings with new, improved midspar fittings in accordance with the Accomplishment Instructions of the service bulletin terminates the repetitive inspections required by paragraphs (f), (h), and (k)(1)(i) of this AD. Actions Accomplished Using Prior Version of Service Information (m) Replacement of the midspar fitting(s) with new, improved fittings before the effective date of this AD in accordance with Boeing Special Attention Service Bulletin 757-54-0042, dated May 13, 1999, is considered acceptable for compliance with the applicable action specified in this AD. Inspection of any fitting accomplished in accordance with Boeing Special Attention Service Bulletin 757-54-0042, dated May 13, 1999, before the effective date of this AD, with no findings of cracking or corrosion, are considered acceptable for compliance with the inspection required by paragraph (f) or (h) of this AD, as applicable, for that fitting only. Previous Nacelle Strut and Wing Modification (n) Accomplishment of the nacelle strut and wing modification required by AD 2003-18-05 is considered acceptable for compliance with the requirements of this AD. Alternative Methods of Compliance (AMOCs) (o)(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 14 CFR 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 replacement required by this AD, if it is approved by a Boeing Company Designated Engineering Representative who has been authorized by the Manager, Seattle ACO, to make those findings. Material Incorporated by Reference (p) You must use Boeing Service Bulletin 757-54-0042, Revision 1, dated July 7, 2005, 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 March 30, 2006. Ali Bahrami, Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 06-3381 Filed 4-10-06; 8:45 am] BILLING CODE 4910-13-P

This AD results from reports of corrosion and cracking on midspar fittings on the nacelle struts of several Boeing Model 757 airplanes. We are issuing this AD to detect and correct cracking in the midspar fittings of the nacelle struts, consequent reduced structural integrity of the struts, and possible separation of an engine and strut from the airplane.