AD 2004-20-02

This amendment adopts a new airworthiness directive (AD), applicable to all Boeing Model 707 and 720 series airplanes, that requires an inspection of the main landing gear (MLG) lock support fitting and the wing fillet flap support link for damage, and corrective action, if necessary; and replacement of the bolts and bushings at the joint between the MLG lock support fitting and the wing fillet flap support link. This action is necessary to prevent stress corrosion cracking of the bolts and wearing of the joint between the lock support fitting and the support link, which could lead to failure of the joint and could cause the collapse of the MLG. This action is intended to address the identified unsafe condition.

Final rule.

2004-20-02 Boeing: Amendment 39-13807. Docket 2003-NM-44-AD. \n\n\tApplicability: All Model 707 and 720 series airplanes, certificated in any category. \n\n\tCompliance: Required as indicated, unless accomplished previously. \n\n\tTo prevent stress corrosion cracking of the bolts and wearing of the joint between the lock support fitting and the support link, which could lead to failure of the joint and could cause the collapse of the main landing gear (MLG), accomplish the following: \n\nService Bulletin References \n\n\t(a) The term "service bulletin," as used in this AD, means the Accomplishment Instructions of Boeing 707 Alert Service Bulletin A3511, dated January 23, 2003. \n\nInitial Inspection \n\n\t(b) Within 12 months or 1,000 flight cycles after the effective date of this AD, whichever comes first, perform a high frequency eddy current (HFEC) inspection of the MLG lock support fitting and the support link for cracks and corrosion in accordance with the service bulletin. \n\nCorrective Actions \n\n\t(c) If any crack or corrosion is found, during the HFEC inspection required by paragraph (b) of this AD, before further flight, rework the lock support fitting or support link, in accordance with the service bulletin, except as specified in paragraphs (c)(1) and (c)(2) of this AD. \n\n\t(1) If the service bulletin specifies to contact Boeing for rework limits: Before further flight, repair or replace the lock support fitting or support link per a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA; or per data meeting the type certification basis of the airplane approved by a Boeing Company Designated Engineering Representative who has been authorized by the Manager, Seattle ACO, to make such findings. For a repair/replacement method to be approved, the approval must specifically reference this AD. \n\n\t(2) Where the service bulletin specifies to rework the forward and aft lug bore and faces common to the lock support fitting of the MLG asgiven in Boeing Service Bulletin 707-2837, this AD requires rework to be accomplished only in accordance with Revision 5 of Boeing 707 Service Bulletin 2837, dated March 31, 1978. \n\nReplacement of Bolts and Bushings \n\n\t(d) Within 12 months or 1,000 flight cycles after the effective date of this AD, whichever comes first, replace the bolts and bushings at the joint between the lock support fitting for the MLG and the wing fillet flap with new CRES bolts and Cadmium-plated Al- Ni-Br bushings in accordance with the service bulletin. \n\nParts Installation \n\n\t(e) As of the effective date of this AD, only bolts specified in paragraph (e)(1) of this AD and bushings specified in paragraph (e)(2) of this AD, may be installed at the joint between the MLG lock support fitting and the support link, on any airplane. \n\n\t(1) CRES bolts, part number (P/N) BACB30LR10DK56 or P/N BACB30LR10DK62. \n\n\t(2) Cadmium-plated aluminum nickel bronze bushings as specified in the service bulletin. \n\nAlternative Methods of Compliance \n\n\t(f) In accordance with 14 CFR 39.19, the Manager, Seattle ACO, FAA, is authorized to approve alternative methods of compliance for this AD. \n\nIncorporation by Reference \n\n\t(g) Unless otherwise specified in this AD, the actions shall be done in accordance with Boeing 707 Alert Service Bulletin A3511, dated January 23, 2003. This 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 Airplanes, 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 National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call (202) 741-6030, or go to: http://www.archives.gov/federal_ register/code_of_federal_regulations/ibr_locations.html. \n\nEffective Date \n\n\t(h) This amendment becomes effective on November 4, 2004.

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 all Boeing Model 707 and 720 series airplanes was published in the Federal Register on February 13, 2004 (69 FR 7174). That action proposed to require an inspection of the main landing gear (MLG) lock support fitting and the wing fillet flap support link for damage, and corrective action, if necessary; and replacement of the bolts and bushings at the joint between the MLG lock support fitting and the wing fillet flap support link. \n\nComment \n\n\tInterested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the one comment received. \n\nRequest To Revise "Parts Installation" Paragraph \n\n\tOne commenter requests to revise "Parts Installation" paragraph (e) of the proposed AD. The commenter suggests including "and no person shall install a bushing other than an aluminum nickel bronze * * *." The commenter notes that the root cause of the unsafe condition of the proposed AD is corrosion and galling between the bolt and steel bushings. \n\n\tWe agree with the commenter. We inadvertently omitted the bushings from paragraph (e) of the proposed AD. As specified in paragraph (d) of the proposed AD, bolts and bushings are to be replaced with new CRES bolts and Cadmium-plated Al-Ni-Br bushings. The intent of paragraph (e) of the proposed AD was to prevent bolts and bushings other than CRES bolts and Cadmium-plated Al-Ni-Br bushings from being installed. We have revised paragraph (e) of the final rule accordingly. \n\nConclusion \n\n\tAfter careful review of the available data, including the comment noted above, we have determined that air safety and the public interest require the adoption of the rule with the changes previously described. We have determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD. \n\nCost Impact \n\n\tThere are approximately 230 airplanes of the affected design in the worldwide fleet. We estimate that 42 airplanes of U.S. registry will be affected by this AD, that it will take approximately 14 work hours per airplane to accomplish the required replacement and inspections, and that the average labor rate is $65 per work hour. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $38,220, or $910 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 accessand 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 ofit 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\nAccordingly, 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\n1. 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\n2. Section 39.13 is amended by adding the following new airworthiness directive: