AD 97-06-04 Airworthiness Directives; Boeing Model 757-200 Series Airplanes

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

Model 757-200 series airplanes having line numbers 1 through 736 inclusive, powered by Rolls Royce 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 modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been otherwise 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 (i) 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 fatigue cracking of the lower spar chord, and consequent reduced structural integrity of the engine strut, accomplish the following: (a) Prior to the accumulation of 15,000 total flight cycles, or within 60 days after the effective date of this AD, whichever occurs later: Perform an eddy current inspection to detect cracking on the free edge of the tang, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 757-54-0031, Revision 2, dated December 19, 1996. Repeat this inspection thereafter at intervals not to exceed 3,000 flight cycles until the inspection required by paragraph (d) of this AD is accomplished. Note 2: The inspection required by paragraph (a) of this AD need not be performed on airplanes on which the inspection required by paragraph (d) of this AD is performed prior to the compliance time specified in paragraph (a) of this AD. (b) If any cracking is found during the inspection required by paragraph (a) of this AD, and the cracking is within the limits specified in the service bulletin: Prior to further flight, remove the midchord channels, stop-drill the cracking, and install a repair in accordance with the service bulletin. No further action is required by this AD. (c) If any cracking is found, and the cracking is outside the limits specified in the service bulletin: Prior to further flight, replace the lower spar chord with a new or serviceable chord in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. (d) Perform an eddy current inspection (bolt hole inspection) to detect cracking of the two fastener holes in the lower spar chord, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 757-54-0031, Revision 2, dated December 19, 1996, at the time specified in paragraph (d)(1) and (d)(2) of this AD, as applicable. Accomplishment of this inspection terminates the inspections required by paragraph (a) of this AD. (1) For airplanes on which the stiffening straps have been removed from the midchord in accordance with Boeing Service Bulletin 757-54-0028 prior to the effective date of this AD: Accomplish the inspection at the time specified in paragraph I.D. of Boeing Service Bulletin 757-54-0031, Revision 2, dated December 19, 1996. (2) For airplanes other than those identified in paragraph (d)(1) of this AD: Accomplish the inspection prior to the accumulation of 18,000 total flight cycles, or within 60 days after the effective date of this AD, whichever occurs later. (e) If no cracking is found during the inspection required by paragraph (d) of this AD, prior to further flight, increase the diameter of the holes by the dimensions specified in the Accomplishment Instructions of Boeing Service Bulletin 757-54-0031, Revision 2, dated December 19, 1996, and install new fasteners in accordance with the service bulletin. (f) If any cracking is found during the inspection required by paragraph (d) of this AD, prior to further flight, accomplish paragraph (f)(1), (f)(2), or (f)(3) of this AD, as applicable, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 757-54-0031, Revision 2, dated December 19, 1996. (1) If the cracking can be removed by increasing the diameter of the hole in accordance with the service bulletin: Increase the diameter of the hole by the dimensions specified in the Accomplishment Instructions of the service bulletin, and install new fasteners in accordance with the service bulletin. (2) If the cracking cannot be removed by increasing the diameter of the hole in accordance with the Accomplishment Instructions of the service bulletin, but the cracking is within the limits specified in the service bulletin: Install the repair in accordance with the service bulletin. No further action is required by this AD. (3) If the cracking is outside the limits specified in the service bulletin: Replace the lower spar chord with a new or serviceable chord in accordance with a method approved by the Manager, Seattle ACO. (g) Accomplish either paragraph (g)(1) or (g)(2) of this AD, as applicable, in accordance with Boeing Service Bulletin 757-54-0031, Revision 2, dated December 19, 1996. (1) If any fastener installed as a result of an inspection required by paragraph (d) of this AD has a diameter of \5/8\-inch or greater: Install the repair prior to the accumulation of the number of flight cycles specified in the ``Subsequent Inspection Interval'' column of the Threshold Table included in paragraph I.D. of the service bulletin. (2) If any fastener installed as a result of an inspection required by paragraph (d) of this AD has a diameter of less than \5/ 8\-inch: Repeat the bolt hole inspection required by paragraph (d) of this AD prior to the accumulation of the number of flight cycles specified in the ``Subsequent Inspection Interval'' column of the Threshold Table included in paragraph I.D. of the service bulletin until the repair specified in paragraph (h) of this AD is installed. (h) Installation of the repair in accordance with the Accomplishment Instructions of Boeing Service Bulletin 757-54-0031, Revision 2, dated December 19, 1996, constitutes terminating action for the requirements of this AD. [[Page 11763]] (i) 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 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO. (j) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished. (k) The actions shall be done in accordance with Boeing Service Bulletin 757-54-0031, Revision 2, dated December 19, 1996. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and CFR part 51. Copies may be obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124-2207. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. (l) This amendment becomes effective on March 28, 1997. Issued in Renton, Washington, on March 5, 1997. Darrell M. Pederson, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 97-6086 Filed 3-12-97; 8:45 am] BILLING CODE 4910-13-U