AD 99-26-09

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 767 series airplanes, that requires repetitive inspections to ensure the proper condition of the engine thrust link components, and follow-on corrective action, if necessary; and replacement of the end cap assembly with an improved assembly. Such replacement, when accomplished, terminates the repetitive inspections. This amendment is prompted by a report of fatigue cracking of end cap bolts caused by improper installation. The actions specified by this AD are intended to prevent failure of the end cap assembly, which could lead to separation of the engine from the airplane in the event of a primary thrust linkage failure.

Final rule

99-26-09 BOEING: Amendment 39-11468. Docket 97-NM-186-AD. Issued December 9, 1999. \n\n\tApplicability: Model 767 series airplanes, powered by Pratt & Whitney Model JT9D or Model PW4000 series engines, as listed in Boeing Alert Service Bulletin 767-71A0087, dated October 10, 1996; 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 (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 requestshould include specific proposed actions to address it. \n\n\tCompliance: Required as indicated, unless accomplished previously. \n\n\tTo prevent possible separation of the engine from the airplane in the event of a primary thrust linkage failure, accomplish the following: \n\nInitial and Repetitive Inspections \n\n\t(a)\tFor Groups 1 and 2 airplanes: Accomplish paragraphs (a)(1), (a)(2), and (a)(3) of this AD, as applicable, in accordance with Boeing Alert Service Bulletin 767-71A0087, dated October 10, 1996. \n\n\t\t(1)\tWithin 500 flight hours or 300 flight cycles after the effective date of this AD, whichever occurs later: Accomplish Work Package 1 (a detailed visual inspection of the forward engine mount to ensure that the thrust link, evener bar, associated lugs, and attaching hardware are firmly attached). Thereafter, repeat Work Package 1 at the intervals specified in the alert service bulletin until the requirements of either paragraph (a)(2) or (a)(3) of this AD are accomplished.NOTE 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 an intensity deemed appropriate by the inspector. Inspection aids such as mirrors, magnifying lenses, etc. may be used. Surface cleaning and elaborate access procedures may be required." \n\n\t(2)\tPrior to the accumulation of 16,000 total flight cycles on any engine or within 500 flight hours or 300 flight cycles after the effective date of this AD, whichever occurs later: Accomplish Work Package 2 (non-destructive test inspection of the forward engine mount to ensure the proper condition of the engine thrust link components). Thereafter, repeat Work Package 2 on that engine at the intervals specified in the alert service bulletin until the requirements of paragraph (a)(3)of this AD are accomplished. Accomplishment of Work Package 2 constitutes terminating action for the repetitive inspections required by paragraph (a)(1) of this AD for that engine. \n\nReplacement and Terminating Action \n\n\t(3)\tWithin 3 years after the effective date of this AD: Accomplish Work Package 3 (end cap and bolt replacement of the forward engine mount). Accomplishment of Work Package 3 constitutes terminating action for the requirements of this AD for Groups 1 and 2 airplanes. \n\n\t(b)\tFor Group 3 airplanes: Within 3 years after the effective date of this AD, accomplish Work Package 4 (bolt replacement) in accordance with Boeing Alert Service Bulletin 767-71A0087, dated October 10, 1996. \n\nRepair and Replacement Action \n\n\t(c)\tFor all airplanes: If any discrepancy (including an improperly installed or damaged engine thrust link component) is found during any inspection required by this AD, prior to further flight, accomplish the actions required by paragraphs (c)(1)and (c)(2) of this AD. (1) Repair any discrepancies in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. For a repair method to be approved by the Manager, Seattle ACO, as required by this paragraph, the Manager's approval letter must specifically reference this AD. (2)\tAccomplish Work Package 3 in accordance with Boeing Alert Service Bulletin 767-71A0087, dated October 10, 1996. \n\nSpares \n\n\t(d)\tAs of the effective date of this AD, no person shall install a forward engine mount end cap having part number 310T3026-1 on any airplane. \n\nAlternative Method of Compliance \n\n\t(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 ACO. 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(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\n\t(g)\tExcept as provided by paragraph (c)(1) of this AD, the actions shall be done in accordance with Boeing Alert Service Bulletin 767-71A0087, dated October 10, 1996. 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) This amendment becomes effective on January 24, 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 767 series airplanes was published as a supplemental notice of proposed rulemaking (NPRM) in the Federal Register on October 21, 1999 (64 FR 56709). That action proposed to require repetitive inspections to ensure the proper condition of the engine thrust link components, and follow-on corrective action, if necessary; and replacement of the end cap assembly with an improved assembly. Such replacement, when accomplished, terminates the repetitive inspections. That action also revises the proposed rule by adding a repair requirement and by clarifying the type of inspection and terminology used in describing the parts to be inspected. \n\nComments \n\n\tInterested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to thesingle comment received. \n\n\tThe Air Transport Association of America (ATA), on behalf of its members, supports the proposed rule. The ATA states that responding members indicated that they had no comment or no objection to the proposed rule. \n\nConclusion \n\n\tAfter 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\n Cost Impact \n\n\tThere are approximately 239 Model 767 series airplanes of the affected design in the worldwide fleet. The FAA estimates that 96 airplanes of U.S. registry will be affected by this AD, that it will take approximately 37 work hours per airplane (18.5 work hours per engine) to accomplish the required inspections, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of this AD on U.S. operators is estimated to be $213,120, or $2,220 per airplane, per inspection cycle. \n\n\tIt will take approximately 135 work hours per airplane (67.5 work hours per engine) to accomplish the required replacement of the forward engine mount end cap and bolts, at an average labor rate of $60 per work hour. Required parts will cost approximately $1,000 per airplane. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $873,600, or $9,100 per airplane. \n\n\tThe 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 \n\n\tThe regulations adopted herein will not have substantial direct effects 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, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment. \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\n Adoption 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: 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: