AD 96-26-51 Airworthiness Directives; Boeing Model 747 Series Airplanes Powered By Rolls Royce Model RB211 Series Engines

Models named: 747 series, RB211 series. Read the applicability below — it usually turns on serial or part numbers too.

Model 747 series airplanes powered by Rolls Royce Model RB211 series engines, certificated in any category. Note 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been otherwise modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (d) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

Required as indicated, unless accomplished previously. To detect and correct cracking of the aft torque bulkhead, which could result in failure of a pylon and consequent separation of the engine from the wing, accomplish the following: (a) Prior to the accumulation of 12,000 total flight cycles, or within 10 days after the effective date of this AD, whichever occurs later, gain access to the aft torque bulkhead at each of the four engine pylons through the aft fairing doors. Prior to further flight after gaining access, accomplish paragraphs (a)(1) and (a)(2) of this AD. (1) Perform a one-time detailed visual inspection to detect cracks and corrosion of the external surface of the lower half of the aft torque bulkhead at all four engine pylons. Pay particular attention to the area near the diagonal brace fitting. (2) Perform a one-time detailed visual inspection to detect cracks and corrosion of the external surface of the inboard and outboard side skin for a distance of 36 inches forward of the plane of the aft torque bulkhead at all four engine pylons. (b) If any crack or corrosion is detected during any inspection required by this AD, prior to further flight, repair the cracked/ corroded pylon in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. (c) Within 10 days after accomplishing the inspections required by paragraphs (a)(1) and (a)(2) of this AD, submit a report of any findings to the Manager, Seattle ACO, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056, fax (206) 227-1181; and to the appropriate FAA Principal Maintenance Inspector. The report shall include the items specified in paragraphs (c)(1), (c)(2), and (c)(3) of this AD. Information collection requirements contained in this regulation have been approved by the Office of Management and Budget (OMB) under the provisions of the Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.) and have been assigned OMB control number 2120-0056. (1) Airplane serial number; (2) Total number of landings accumulated; and (3) Location, size, and orientation of each crack. (d) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Seattle ACO. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Seattle ACO. Note 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO. (e) This amendment becomes effective on January 13, 1997, to all persons except those persons to whom it was made immediately effective by telegraphic AD T96-26-51, issued on December 13, 1996, which contained the requirements of this amendment. Issued in Renton, Washington, on December 31, 1996. S.R. Miller, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 97-255 Filed 1-7-97; 8:45 am] BILLING CODE 4910-13-U