AD 94-14-01

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 767 series airplanes, that requires replacement of the thrust reverser flow restrictor devices with one-way (check) valve restrictors. This amendment is prompted by reports of piston seal leakage found during actuator overhaul on certain Model 767 series airplanes. The actions specified by this AD are intended to prevent possible deployment of a thrust reverser in flight and subsequent reduced controllability of the airplane.

Final rule

94-14-01 BOEING: Amendment 39-8953. Docket 94-NM-13-AD. \n\n\tApplicability: Model 767 series airplanes equipped with General Electric CF6-80A or Pratt & Whitney JT9D-7R4 engines, certificated in any category. \n\n\tCompliance: Required as indicated, unless accomplished previously. \n\n\tTo prevent possible deployment of a thrust reverser in flight and subsequent reduced controllability of the airplane, accomplish the following: \n\n\t(a)\tWithin 18 months after the effective date of this AD, replace the thrust reverser flow restrictor devices with one-way (check) valve restrictors in accordance with Boeing Alert Service Bulletin 767-78-0064 (for Model 767 series airplanes equipped with General Electric CF6-80A engines) or 767-78-0065 (for Model 767 series airplanes equipped with Pratt & Whitney JT9D-7R4 engines), both dated July 16, 1992, as applicable. \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\nNOTE: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO. \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\n\t(d)\tThe replacement shall be done in accordance with Boeing Alert Service Bulletin 767- 78-0064, dated July 16, 1992, or Boeing Alert Service Bulletin 767-78-0065, dated July 16, 1992, 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\t(e)\tThis amendment becomes effective on August 1, 1994.

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 in the Federal Register on March 16, 1994 (59 FR 12207). That action proposed to require replacement of the thrust reverser flow restrictor devices with one-way (check) valve restrictors. \n\n\tInterested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the two comments received. \n\n\tBoth commenters support the proposed rule. \n\n\tAfter careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule as proposed. \n\n\tThere are approximately 119 Model 767 series airplanes equipped with General Electric CF6-80A engines of the affected design in the worldwide fleet. The FAA estimates that 69 airplanes of U.S. registry will be affected by this AD, that it will take approximately 32 work hours per airplane to accomplish the required actions, and that the average labor rate is $55 per work hour. Required parts will be supplied by the manufacturer at no cost to operators. Based on these figures, the total cost impact of the AD on U.S. operators of Model 767 series airplanes equipped with General Electric CF6-80A engines is estimated to be $121,440, or $1,760 per airplane. \n\n\tThere are approximately 95 Model 767 series airplanes equipped with Pratt & Whitney JT9D-7R4 engines of the affected design in the worldwide fleet. The FAA estimates that 30 airplanes of U.S. registry will be affected by this AD, that it will take approximately 30 work hours per airplane to accomplish the required actions, and that the average labor rate is $55 per work hour. Required parts will be supplied by the manufacturer at no cost to operators. Based on these figures, the totalcost impact of the AD on U.S. operators of Model 767 series airplanes equipped with Pratt & Whitney JT9D-7R4 engines is estimated to be $49,500, or $1,650 per airplane. \n\n\tBased on these figures, the total cost impact of the AD on U.S. operators is estimated to be $170,940. \n\n\tThe total 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. \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\n List of Subjects in 14 CFR Part 39 \n\nAir 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: PART 39 - AIRWORTHINESS DIRECTIVES \n\n1.\tThe authority citation for part 39 continues to read as follows: Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C. 106(g); and 14 CFR 11.89. § 39.13 - (Amended) \n\n2.\tSection 39.13 is amended by adding the following new airworthiness directive: