AD 97-14-06 Airworthiness Directives; Boeing Model 747 Series Airplanes, Excluding Airplanes Equipped With Pratt & Whitney PW4000 and General Electric CF6-80C2 Series Engines

Models named: 747, 747-400 series. Read the applicability below — it usually turns on serial or part numbers too.

Model 747 and 747-400 series airplanes, line numbers 1 through 967 inclusive, and 969 through 992 inclusive; certificated in any category; excluding airplanes equipped with Pratt & Whitney PW4000 or General Electric CF6-80C2 series engines; and excluding airplanes on which the strut/wing modification has been accomplished in accordance with AD 95-13-05, amendment 39-9285, AD 95-13-07, amendment 39-9287; or AD 95-10-16, amendment 39-9233. Note 1: This AD does not require that the actions be accomplished on those airplanes having pylons on which 15-5 corrosion resistant steel (third generation) fuse pins are installed through the upper link of the inboard and outboard struts. Note 2: 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 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 (h) 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 prevent failure of the strut and loss of an engine due to corrosion or cracking of the fuse pins, accomplish the following: (a) For airplanes having bottle bore style fuse pins in the forward position on the upper link: Replace any bottle bore style fuse pin with a new bulkhead style fuse pin in the forward position, or with 15-5 corrosion resistant steel (third generation) fuse pins in the forward position, in accordance with Boeing Alert Service Bulletin 747-54A2166, dated April 28, 1994, or Revision 1, dated May 1, 1997, at the later of the times specified in paragraphs (a)(1) and (a)(2) of this AD. (1) Prior to the accumulation of 5,000 total landings on the fuse pin, or within 5 years since installation of the pin, whichever occurs first. Or (2) Within 6 months after April 13, 1995 (the effective date of AD 95-06-02, amendment 39-9172). Note 3: Third generation fuse pins are installed in pairs (in the forward and aft positions). Therefore, replacement of an individual upper link fuse pin in the forward position with a third generation pin also would necessitate replacement of the pin in the aft position. Note 4: The alert service bulletin references Boeing Service Bulletin 747-54-2155, dated September 23, 1993, as an additional source of service information for replacement of the fuse pins with 15-5 corrosion resistant steel (third generation) fuse pins. Installation of these third generation fuse pins is preferred over installation of bulkhead style fuse pins. (b) For airplanes having bulkhead style fuse pins in the forward position on the upper link: Perform a detailed visual inspection to detect corrosion of the pins, and a magnetic particle inspection to detect cracks, in accordance with Boeing Alert Service Bulletin 747- 54A2166, dated April 28, 1994, or Revision 1, dated May 1, 1997, at the earlier of the times specified in paragraphs (b)(1) and (b)(2) of this AD. (1) Perform the inspections at the later of the times specified in paragraphs (b)(1)(i) and (b)(1)(ii) of this AD. (i) Prior to the accumulation of 8,000 total landings on the fuse pin, or within 8 years since installation of the pin, whichever occurs first. Or (ii) Within 12 months after April 13, 1995. (2) Perform the inspections at the later of the times specified in paragraphs (b)(2)(i) and (b)(2)(ii) of this AD. (i) Prior to the accumulation of 5,000 total landings on the fuse pin, or within 5 years since installation of the pin, whichever occurs first. Or (ii) Within 90 days after the effective date of this AD. (c) For the inboard and outboard struts on airplanes other than those identified in paragraph (d) of this AD: If no corrosion or crack is found during the inspection required by paragraph (b) of this AD, repeat the inspection thereafter, in accordance with Boeing Alert Service Bulletin 747-54A2166, dated April 28, 1994, or Revision 1, dated May 1, 1997, at the time specified in paragraph (c)(1) or (c)(2) of this AD, as applicable. (1) For airplanes on which the initial inspection required by paragraph (a) or (b) of AD 95-06-02 has been accomplished prior to the effective date of this AD: Repeat the inspection within 1,000 landings since the last inspection in accordance with AD 95-06-02, or within 500 landings after the effective date of this AD, whichever occurs first, and thereafter at intervals not to exceed 500 landings. (2) For airplanes other than those identified in paragraph (c)(1) of this AD: Repeat the inspection thereafter at intervals not to exceed 500 landings. (d) For the outboard struts on airplanes equipped with Rolls- Royce RB211-524G or -524H series engines: If no corrosion or crack is found during the inspection required by paragraph (b) of this AD, repeat the inspection thereafter in accordance with Boeing Alert Service Bulletin 747-54A2166, dated April 28, 1994, or Revision 1, dated May 1, 1997, at the time specified in paragraph (d)(1) or (d)(2) of this AD, as applicable. (1) For airplanes on which the initial inspection required by paragraph (a) or (b) of AD 95-06-02 has been accomplished prior to the effective date of this AD: Repeat the inspection within 2,000 landings since the last inspection in accordance with AD 95-06-02, or within 1,000 landings after the effective date of this AD, whichever occurs first, and thereafter at intervals not to exceed 500 landings. (2) For airplanes other than those identified in paragraph (d)(1) of this AD: Repeat the inspection thereafter at intervals not to exceed 500 landings. Note 5: The outboard struts of airplanes equipped with Rolls- Royce RB211-524G or -524H series engines are equipped with thick wall ``4330 steel'' bulkhead style fuse pins in the forward position of the upper link. Crack propagation to critical length in these thick wall pins is slower than for pins installed on the struts of airplanes equipped with engines other than the Rolls-Royce RB211- 524G or -524H series. (e) If any corrosion or crack is found during any inspection required by this AD, prior to further flight, replace the corroded or cracked pin with either a new bulkhead style fuse pin in the forward position of the upper link, or with 15-5 corrosion resistant steel (third generation) fuse pins in the forward and aft positions of the upper link; in accordance with Boeing Alert Service Bulletin 747-54A2166, dated April 28, 1994, or Revision 1, dated May 1, 1997. Accomplish inspections, if applicable, as specified in paragraph (e)(1) or (e)(2). (1) If the corroded or cracked fuse pin is replaced with a new bulkhead style fuse pin, prior to the accumulation of 5,000 total landings on the new pin, or within 5 years since installation of the new pin, whichever occurs first, perform a detailed visual inspection to detect corrosion of the new pin, and a magnetic particle inspection to detect cracks of the new pin, in accordance with the alert service bulletin. Repeat these inspections thereafter at the interval specified in paragraph (e)(1)(i) or (e)(1)(ii) of this AD, as applicable. (i) For the inboard and outboard struts on airplanes other than those identified in paragraph (e)(1)(ii) of this AD: Repeat the inspections at intervals not to exceed 500 landings. (ii) For the outboard struts on airplanes equipped with Rolls- Royce RB211-524G or -524H series engines: Repeat the inspections at intervals not to exceed 1,000 landings. (2) If the corroded or cracked fuse pin is replaced with a 15-5 corrosion resistant steel (third generation) fuse pin, no further action is required by this AD. (f) Accomplishment of the strut/wing modification in accordance with Boeing Alert Service Bulletin 747-54A2166, Revision 1, dated May 1, 1997, constitutes terminating action for the requirements of this AD. [[Page 35956]] Note 6: Boeing Alert Service Bulletin 747-54A2166, Revision 1, references Boeing Alert Service Bulletins 747-54A2157, 747-54A2158, and 747-54A2159 as additional sources of service information for accomplishment of the strut/wing modification. (g) Installation of 15-5 corrosion resistant steel (third generation) fuse pins in the forward and aft positions of the upper link on the inboard or outboard strut in accordance with Boeing Alert Service Bulletin 747-54A2166, Revision 1, dated May 1, 1997, constitutes terminating action for the requirements of this AD. (h) 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 Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. 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 7: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO. (i) 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. (j) The actions shall be done in accordance with Boeing Alert Service Bulletin 747-54A2166, dated April 28, 1994, or Revision 1, dated May 1, 1997. The incorporation by reference of Boeing Alert Service Bulletin 747-54A2166, dated April 28, 1994, was approved previously by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51 as of April 13, 1995 (60 FR 13618, March 14, 1995). The incorporation by reference of Boeing Alert Service Bulletin 747-54A2166, Revision 1, dated May 1, 1997, was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 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. (k) This amendment becomes effective on July 18, 1997. Issued in Renton, Washington, on June 26, 1997. S.R. Miller, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 97-17284 Filed 7-2-97; 8:45 am] BILLING CODE 4910-13-U