AD 97-20-01 Airworthiness Directives; Boeing Model 747 Series Airplanes

Models named: 747 series, JT9D-3, - 7, or -7Q, CF6 series. Read the applicability below — it usually turns on serial or part numbers too.

Model 747 series airplanes, having line numbers 1 through 500 inclusive, equipped with Pratt & Whitney Model JT9D-3, - 7, or -7Q engines, or having line numbers 202, 204, 232, or 257, equipped with General Electric Model CF6 series engines; certificated in any category; and on which the strut/wing modification has not been accomplished in accordance with either of the following AD's: AD 95-10-16, amendment 39-9233 (60 FR 27008, May 22, 1995), or AD 95-13-07, amendment 39-9287 (60 FR 33336, June 28, 1995). 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 (c)(1) 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 in the lower spar fitting lug or the lower spar fitting body, which could result in failure of the strut and separation of the engine from the airplane, accomplish the following: (a) Within 90 days after October 7, 1997 (the effective date of AD 97-20-01, amendment 39-10139) perform a detailed visual inspection and an ultrasonic inspection to detect cracks, corrosion, or damage of the lower spar fitting body and lug, as applicable, in accordance with Figures 9 and 10 of Boeing Service Bulletin 747-54- 2062, Revision 8, dated August 21, 1997. Note 2: This AD does not require an inspection of the inboard strut-to-diagonal brace attach fitting as described in Figure 1 of Boeing Service Bulletin 747-54-2062, Revision 8, dated August 21, 1997. However, this inspection is required to be accomplished as part of AD 95-20-05, amendment 39-9383 (60 FR 51705, October 10, 1995). (1) If no crack, corrosion, or damage is detected, repeat the detailed visual and ultrasonic inspections thereafter at intervals not to exceed 400 landings. (2) If any crack, corrosion, or damage is detected, prior to further flight, accomplish either paragraph (a)(2)(i) or (a)(2)(ii) of this AD. (i) Replace the lower spar fitting with a new steel lower spar fitting, in accordance with Part II of the Accomplishment Instructions of the service bulletin. Or (ii) Modify the nacelle strut and wing structure in accordance with AD 95-10-16, amendment 39-9233 (60 FR 27008, May 22, 1995), or AD 95-13-07, amendment 39-9287 (60 FR 33336, June 28, 1995). (b) Replacement of the lower spar fitting with a new steel lower spar fitting, in accordance with Part II of the Accomplishment Instructions of any of the following service bulletins listed below, or accomplishment of modification of the nacelle strut and wing structure required by AD 95-10-16, amendment 39-9233 (60 FR 27008, May 22, 1995), or AD 95-13-07, amendment 39-9287 (60 FR 33336, June 28, 1995); constitutes terminating action for the repetitive inspection requirements of this AD. Boeing Service Bulletin 747-54-2062, Revision 1, dated November 13, 1980; Boeing Service Bulletin 747-54-2062, Revision 2, dated March 19, 1981; Boeing Service Bulletin 747-54-2062, Revision 3, dated August 28, 1981; Boeing Service Bulletin 747-54-2062, Revision 4, dated June 30, 1982; Boeing Service Bulletin 747-54-2062, Revision 5, dated June 1, 1984; Boeing Service Bulletin 747-54-2062, Revision 6, dated October 2, 1986; Boeing Service Bulletin 747-54-2062, Revision 7, dated December 21, 1994; Boeing Service Bulletin 747-54-2062, Revision 8, dated August 21, 1997. (c)(1) 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. (2) Alternative methods of compliance, approved previously in accordance with AD 97-20-01, are approved as alternative methods of compliance with the requirements of this AD. Note 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO. (d) 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. (e) Certain actions shall be done in accordance with Boeing Service Bulletin 747-54-2062, Revision 8, dated August 21, 1997. The incorporation by reference of this document 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 October 7, 1997 (62 FR 49431, September 22, 1997). 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, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. (f) This amendment becomes effective on February 11, 1999. Issued in Renton, Washington, on December 30, 1998. Darrell M. Pederson, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 99-186 Filed 1-6-99; 8:45 am] BILLING CODE 4910-13-P