AD 99-26-02

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 747-400 and 767 series airplanes, that requires replacement of the existing deactivation pin, pin bushing, and insert flange on each thrust reverser half, with new, improved components. This amendment is prompted by reports of partial deployment of deactivated thrust reversers during landing. The actions specified by this AD are intended to prevent failure of the thrust reverser deactivation pins, which could result in deployment of the thrust reverser in flight and consequent reduced controllability of the airplane.

Final rule

99-26-02 BOEING: Amendment 39-11462. Docket 99-NM-114-AD. \n\n\tApplicability: Model 747-400 series airplanes powered by Pratt & Whitney PW4000 series engines, as listed in Boeing Service Bulletin 747-78A2165, Revision 1, dated May 13, 1999; and Model 767 series airplanes powered by Pratt & Whitney PW4000 series engines, as listed in Boeing Alert Service Bulletin 767-78A0080, dated February 25, 1999; 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 (b) 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 failure of the thrust reverser deactivation pins, which could result in deployment of the thrust reverser in flight and consequent reduced controllability of the airplane, accomplish the following: \n\nReplacement \n\n(a)\tWithin 24 months after the effective date of this AD, replace the existing deactivation pin, pin bushing in the aft cascade mounting ring, and insert flange on each thrust reverser half, with new, improved components, in accordance with Boeing Service Bulletin 747-78A2165, Revision 1, dated May 13, 1999 (for Model 747-400 series airplanes); or Boeing Alert Service Bulletin 767-78A0080, dated February 25, 1999 (for Model 767 series airplanes); as applicable. NOTE 2: The new, improved insert flange and pin bushing does not preclude use of a deactivation pin having P/N 315T1604-2 or -5. However, use of deactivation pins having P/N 315T1604-2 or -5 may not prevent the thrust reversers from deploying in event of a full powered deployment. Therefore, thrust reversers modified per this AD require installation of the new, longer deactivation pins having P/N 315T1604-6, as specified in the applicable service bulletin. NOTE 3: Replacements accomplished prior to the effective date of this AD in accordance with Boeing Alert Service Bulletin 747-78A2165, dated February 25, 1999, are considered acceptable for compliance with the applicable action specified in this amendment. \n\nAlternative Methods of Compliance \n\n\t(b)\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\n\tNOTE 4: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO.\n\n Special Flight Permits \n\n\t(c)\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(d)\tThe actions shall be done in accordance with Boeing Service Bulletin 747-78A2165, Revision 1, dated May 13, 1999, or Boeing Alert Service Bulletin 767-78A0080, dated February 25, 1999, as applicable. 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(e) 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 747-400 and 767 series airplanes was published in the Federal Register on September 15, 1999 (64 FR 50022). That action proposed to require replacement of the existing deactivation pin, pin bushing, and insert flange on each thrust reverser half, with new, improved components. \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 the single comment received. \n\n\tThe commenter supports 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\nCost Impact \n\n\tThere are approximately 201 airplanes of the affected design inthe worldwide fleet. The FAA estimates that 39 Model 747-400 series airplanes and 54 Model 767 series airplanes of U.S. registry will be affected by this AD. It will take approximately 6 work hours per engine accomplish the required replacement, at an average labor rate of $60 per work hour. Required parts will cost approximately $3,956 per engine. Based on these figures, the cost impact of this AD on U.S. operators of Model 747-400 series airplanes (4 engines per airplane) is estimated to be $673,296, or $17,264 per airplane. The cost impact of this AD on U.S. operators of Model 767 series airplanes (2 engines per airplane) is estimated to be $466,128, or $8,632 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 willnot 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\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: 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: