AD 2000-07-13

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 757-200 and -200PF series airplanes, that requires repetitive detailed visual inspections to detect loose fuse pins in the outboard beam attachment and forward trunnion support on the main landing gear (MLG) and to detect corrosion on the structure adjacent to the fuse pin; and corrective actions, if necessary. This amendment also requires eventual replacement of the fuse pins with new corrosion resistant steel (CRES) fuse pins, which constitutes terminating action for the repetitive inspections. This amendment is prompted by a report of damaged fuse pins caused by corrosion. The actions specified by this AD are intended to prevent corroded fuse pins, which could result in the MLG separating from the wing, and consequent damage to the airplane and possible rupture of the wing fuel tank.

Final rule

2000-07-13 BOEING: Amendment 39-11667. Docket 99-NM-57-AD. \n\nApplicability: Model 757-200 and -200PF series airplanes, line numbers 1 through 806 inclusive; certificated in any category. \n\nNOTE 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 (e) 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\nCompliance: Required as indicated, unless accomplished previously. \n\nTo prevent corroded fuse pins, which could result in the main landing gear (MLG) separating from the wing, and consequent damage to the airplane and possible rupture of the wing fuel tank, accomplish the following: \n\nRepetitive Inspections \n(a)\tPerform a detailed visual inspection to detect loose fuse pins in the outboard beam attachment and forward trunnion support on the MLG and to detect corrosion on the structure adjacent to the fuse pin, in accordance with Boeing Alert Service Bulletin 757-57A0054, including Appendix A, dated November 5, 1998, or Boeing Service Bulletin 757-57A0054, Revision 1, including Appendix A, dated December 16, 1999; at the later of the times specified in paragraphs (a)(1) and (a)(2) of this AD. Thereafter, repeat the inspection at intervals not to exceed 3,000 flight cycles or 24 months, whichever occurs first, until accomplishment of paragraph (d) of this AD. \n\n(1)\tPrior to 4 years since date of manufacture of the airplane; or \n\n(2)\tWithin 3,000 flight cycles or 24 months after the effective date of this AD, whichever occurs first. \n\nNOTE 2: For the purposes of this AD, a detailed visual inspection is defined as: "An intensive visual examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at intensity deemed appropriate by the inspector. Inspection aids such as mirror, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required." \n\n(b)\tFor airplanes on which the alloy steel fuse pins were replaced prior to the effective date of this AD: Perform the initial inspection required by paragraph (a) of this AD within 4 years or 6,000 flight cycles after installation of the pins, whichever occurs later. Thereafter, accomplish the repetitive inspections required by paragraph (a) of this AD at the time specified in that paragraph.Corrective Action \n(c)\tIf any loose fuse pin or corrosion on the structure adjacent to the fuse pin is detected during any inspection required by paragraph (a) of this AD, prior to further flight, perform the applicable corrective action (i.e., detailed visual inspections for cracks or corrosion, repair of discrepant parts, and replacement of fuse pin) in accordance with Boeing Alert Service Bulletin 757-57A0054, including Appendix A, dated November 5, 1998, or Boeing Service Bulletin 757-57A0054, Revision 1, including Appendix A, dated December 16, 1999. Replacement of an alloy steel fuse pin with a new corrosion resistant steel (CRES) fuse pin constitutes terminating action for the repetitive inspection requirements of paragraph (a) of this AD for that fuse pin only. \n\nTerminating Action \n(d)\tAt the next scheduled MLG overhaul, or within 12 years after the effective date of this AD, whichever occurs first, replace all alloy steel fuse pins with new CRES fuse pins in the outboard beam attachment and forward trunnion support on the MLG in accordance with Boeing Alert Service Bulletin 757-57A0054, including Appendix A, dated November 5, 1998, or Boeing Service Bulletin 757-57A0054, Revision 1, including Appendix A, dated December 16, 1999. Accomplishment of the action specified in this paragraph constitutes terminating action for the repetitive inspection requirements of this AD. \n\nAlternative Methods of Compliance \n(e)\tAn 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. \n\nNOTE 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(f)\tSpecial 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(g)\tThe actions shall be done in accordance with Boeing Alert Service Bulletin 757-57A0054, including Appendix A, dated November 5, 1998, or Boeing Service Bulletin 757-57A0054, Revision 1, including Appendix A, dated December 16, 1999. 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 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\n(h)\tThis amendment becomes effective on May 16, 2000.

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 757-200 and -200PF series airplanes was published in the Federal Register on October 6, 1999 (64 FR 54227). That action proposed to require repetitive detailed visual inspections to detect loose fuse pins in the outboard beam attachment and forward trunnion support on the main landing gear (MLG) and to detect corrosion on the structure adjacent to the fuse pin; and corrective actions, if necessary. That action also proposed to require eventual replacement of the fuse pins with new corrosion resistant steel (CRES) fuse pins, which would constitute terminating action for the repetitive inspections. \n\nInterested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the single comment received. \n\nRequest to Change Repetitive Inspection Interval\nThe commenter requests that the proposed repetitive inspection interval be changed from 3,000 flight cycles or 24 months (whichever occurs first) to either 36 months or to 3,000 flight cycles or 24 months (whichever is later). The commenter states that 3,000 flight cycles does not correspond to the 24-month calendar time. The commenter adds that 36 months would more closely reflect the amount of time it takes for its airplanes to accumulate 3,000 flight cycles. \n\nThe FAA does not concur with this request. This AD addresses corrosion of the fuse pins, which is a time-related phenomenon. Therefore, the critical element of the repetitive inspection interval in this case is the amount of calendar time that passes between inspections, rather than the number of flight cycles accumulated. Therefore, the FAA finds that the repetitive inspection interval of 3,000 flight cycles or 24 months, whichever occurs first, is appropriate to address the identified unsafe condition in a timely manner and to ensure an adequate level of safety. No change to the final rule is necessary. \n\nRevised Service Information \nSince the issuance of the proposed AD, the FAA has reviewed and approved Boeing Service Bulletin 757-57A0054, Revision 1, including Appendix A, both dated December 16, 1999. (The original issue of the service bulletin is referenced in the proposal as the appropriate source of service information for accomplishment of the actions required by this AD.) \n\nRevision 1 is essentially equivalent to the original issue; however, Revision 1 adds references to optional parts and changes certain compliance recommendations. Revision 1 recommends that, if the alloy steel fuse pins have already been replaced on an airplane that was four years (or more) old, the inspection of those pins can be extended to within four years or 6,000 flight cycles after installation. A new paragraph (b) has been added to the final rule to specify the revised compliance time for those particular airplanes. \n\nThe FAA also has revised the final rule to include Revision 1 of the service bulletin as an additional source of service information. Further, the FAA has revised references to the original issue of the service bulletin to include Appendix A, dated November 5, 1998. \n\nConclusion \nAfter careful review of the available data, including the comment noted above, the FAA has determined that air safety and the public interest require the adoption of the rule as proposed. \n\nCost Impact \nThere are approximately 805 airplanes of the affected design in the worldwide fleet. The FAA estimates that 350 airplanes of U.S. registry will be affected by this AD. \n\nIt will take approximately 1 work hour per airplane to accomplish the required inspection, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the inspection required by this AD on U.S. operators is estimated to be $21,000, or $60 per airplane, per inspection cycle. \n\nIt will take approximately 440 work hours per airplane to accomplish the required replacement, at an average labor rate of $60 per work hour. The manufacturer has committed previously to its customers that it will bear the cost of replacement parts. As a result, the cost of those parts are not attributable to this AD. Based on these figures, the cost impact of the replacement required by this AD on U.S. operators is estimated to be $9,240,000, or $26,400 per airplane. \n\nThe cost impact figures discussed above are 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. \n\nRegulatory Impact \nThe 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\nFor 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 \nAir transportation, Aircraft, Aviation safety, Incorporation by reference, Safety. \n\nAdoption of the Amendment \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: PART 39 - AIRWORTHINESS DIRECTIVES \n\t1. The authority citation for part 39 continues to read as follows: Authority: 49 U.S.C. 106(g), 40113, 44701. § 39.13 (Amended) \n\t2. Section 39.13 is amended by adding the following new airworthiness directive: