AD 2001-17-24

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 707 and 720 series airplanes, that requires a preventive modification of the front spar fitting on the outboard engine nacelle. This action is necessary to prevent fatigue cracking of the front spar fitting on the outboard engine nacelle, which could reduce the structural integrity of the nacelle, and result in separation of the engine from the airplane. This action is intended to address the identified unsafe condition.

Final rule.

2001-17-24 Boeing: Amendment 39-12415. Docket 2000-NM-378-AD. \n\n\tApplicability: Model 707 and 720 series airplanes, as listed in Boeing Service Bulletin 1541, Revision 3, dated February 15, 1967; certificated in any category. \n\n\tNote 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 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) 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. \n\n\tCompliance: Required as indicated, unless accomplished previously. \n\n\tTo prevent fatigue cracking of the front spar fitting on the outboard engine nacelle, which could reduce the structural integrity of the nacelle, and result in separation of the engine from the airplane, accomplish the following: \n\nPreventive Modification \n\n\t(a) Prior to the accumulation of 20,000 total flight cycles, or within 24 months after the effective date of this AD, whichever occurs later, install the preventive modification of the front spar fitting on the outboard engine nacelle. Do the modification (including replacement of the front spar fitting with a new, improved (stronger) fitting, and modification of the front spar chord to distribute stress loads over the entire front spar fitting) according to Boeing Service Bulletin 1541, Revision 3, dated February 15, 1967. \n\n\tNote 2: Modification of the front spar fitting on the outboard engine nacelle (including replacement of the front spar fitting with a new, improved (stronger) fitting, and modification of the front spar chord to distribute stress loads over the entire front spar fitting) accomplished prior to the effective date of this AD according to Boeing Service Bulletin 1541, dated July 1, 1962; Revision 1, dated January 29, 1963; Revision 2, dated February 11, 1964; or Supplement 1541(R-2)A, dated April 2, 1964; is acceptable for compliance with the requirements of paragraph (a) of this AD. \n\nSpares \n\n\t(b) As of the effective date of this AD, no person shall install a front spar fitting, part number 65-2532 or 65-2532-5, on the outboard engine nacelle on any airplane. \n\nAlternative Methods of Compliance \n\n\t(c) 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. 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. \n\n\tNote 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO. \n\nSpecial Flight Permits \n\n\t(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. \n\nIncorporation by Reference \n\n\t(e) The preventive modification shall be done in accordance with Boeing Service Bulletin 1541, Revision 3, dated February 15, 1967, which contains the following effective pages: \n\n\nPage No. \nRevision level shown on page \nDate shown on page\n1-4\n3\n\nFeb. 15, 1967.\n5-21\nSupplement 1541(R-2)A. \nApr. 2, 1964. \n\n\tThis incorporation by reference 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. \n\nEffective Date \n\n\t(f) This amendment becomes effective on October 3, 2001.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to certain Boeing Model 707 and 720 series airplanes was published in the Federal Register on June 5, 2001 (66 FR 30105). That action proposed to require a preventive modification of the front spar fitting on the outboard engine nacelle. \n\nComments \n\n\tInterested persons have been afforded an opportunity to participate in the making of this amendment. No comments were submitted in response to the proposal or the FAA's determination of the cost to the public. \n\nConclusion \n\n\tThe FAA has determined that air safety and the public interest require the adoption of the rule as proposed. \n\nCost Impact \n\n\tThere are approximately 13 Model 707 and 720 series airplanes of the affected design in the worldwide fleet. The FAA estimates that 3 airplanes of U.S. registry will be affected by this AD, that it will take approximately 64 work hours per airplane to accomplish the required modification, and that the average labor rate is $60 per work hour. Required parts will cost approximately $1,300 per airplane. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $15,420, or $5,140 per airplane. \n\n\tThe cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted. The cost impact figures discussed in AD rulemaking actions represent only the time necessary to perform the specific actions actually required by the AD. These figures typically do not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions. \n\nRegulatory Impact \n\n\tThe regulations adopted herein will not have a substantial direct effect on the States, on the relationship between the national Government and the States, or on the distribution of power and responsibilities among the various levels of government. Therefore, it is determined that this final rule does not have federalism implications under Executive Order 13132. \n\n\tFor the reasons discussed above, I certify that this action (1) is not a "significant regulatory action" under Executive Order 12866; (2) is not a "significant rule" under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it may be obtained from the Rules Docket at the location provided under the caption ADDRESSES. \n\nList of Subjects in 14 CFR Part 39 \n\n\tAir transportation, Aircraft, Aviation safety, Incorporation by reference, Safety. \n\nAdoption of the Amendment \n\n\tAccordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows: \n\nPART 39--AIRWORTHINESS DIRECTIVES \n\n\t1. The authority citation for part 39 continues to read as follows: \n\n\tAuthority: 49 U.S.C. 106(g), 40113, 44701. \n\nSec. 39.13 (Amended) \n\n\t2. Section 39.13 is amended by adding the following new airworthiness directive: