Airworthiness Directive · Amendment 39-11538 · Boeing Model 767 Series Airplanes Equipped With General Electric Model CF6-80C2 Series Engines
Boeing Model 767 Series Airplanes Equipped With General Electric Model CF6-80C2 Series Engines
Superseded. A later AD replaced this one: AD 2000-09-04. Comply with the one in force.
Model 767 series airplanes equipped with General Electric Model CF6-80C2 series engines, certificated in any category.
Note 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 (i)(1) 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.
This amendment supersedes an existing airworthiness directive (AD), applicable to certain Boeing Model 767 series airplanes, that currently requires tests, inspections, and adjustments of the thrust reverser system. That AD also requires installation of a terminating modification, and repetitive follow-on actions. This amendment reduces the repetitive intervals for the follow-on actions. This amendment is prompted by reports indicating that several center drive units (CDU's) of the thrust reverser system were returned to the manufacturer of the CDU's because of low holding torque of the CDU cone brake. The actions specified by this AD are intended to ensure the integrity of the fail safe features of the thrust reverser system by preventing possible failure modes in the thrust reverser control system that can result in inadvertent deployment of a thrust reverser during flight.
To ensure the integrity of the fail safe features of the thrust reverser system by preventing possible failure modes in the thrust reverser control system that can result in inadvertent deployment of a thrust reverser during flight, accomplish the following:
(a) Within 30 days after August 18, 1995 (the effective date of AD 95-13-12 R1, amendment 39-9528), perform tests, inspections, and adjustments of the thrust reverser system in accordance with Boeing Service Bulletin 767-78-0047, Revision 3, dated July 28, 1994.
(1) Except as provided by paragraph (a)(2) of this AD, repeat all tests and inspections thereafter at intervals not to exceed 3,000 flight hours until the modification required by paragraph (c) of this AD is accomplished.
(2) Repeat the check of the grounding wire for the Directional Pilot Valve (DPV) of the thrust reverser in accordance with the service bulletin at intervals not to exceed 1,500 flight hours, and whenever maintenance action is taken that would disturb the DPV grounding circuit, until the modification required by paragraph (c) of this AD is accomplished.
(b) If any of the tests and/or inspections required by paragraph (a) of this AD cannot be successfully performed, or if those tests and/or inspections result in findings that are unacceptable in accordance with Boeing Service Bulletin 767-78-0047, Revision 3, dated July 28, 1994; accomplish paragraphs (b)(1) and (b)(2) of this AD.
(1) Prior to further flight, deactivate the associated thrust reverser in accordance with Section 78-31-1 of Boeing Document D630T002, “Boeing 767 Dispatch Deviation Guide,” Revision 9, dated May 1, 1991; or Revision 10, dated September 1, 1992. After August 18, 1995, this action shall be accomplished only in accordance with Revision 10 of the Boeing document. No more than one reverser on any airplane may be deactivated under the provisions of this paragraph.
(2) Within 10 days after deactivation of any thrust reverser in accordance with this paragraph, the thrust reverser must be repaired in accordance with Boeing Service Bulletin 767-78-0047, Revision 3, dated July 28, 1994. Additionally, the tests and/or inspections required by paragraph (a) of this AD must be successfully accomplished; once this is accomplished, the thrust reverser must then be reactivated.
(c) For airplanes having line numbers 1 through 474 inclusive: Within 3 years after August 18, 1995, install a third locking system on the left- and right-hand engine thrust reversers in accordance with Boeing Service Bulletin 767-78-0063, Revision 2, dated April 28, 1994.
Note 2: Model 767 series airplanes equipped with General Electric Model CF6-80C2 series engines and having line numbers 475 and subsequent, on which Production Revision Record (PRR) B11481-70 (which installs a third locking system on the left- and right-hand engine thrust reversers) has been incorporated, need NOT be modified in accordance with Boeing Service Bulletin 767-78-0063, Revision 2.
Note 3: Boeing Service Bulletin 767-78-0063, references General Electric (GE) Service Bulletin 78-135 as an additional source of service information for accomplishment of the third locking system on the thrust reversers. However, the Boeing Service Bulletin does not specify the appropriate revision level, and the GE service bulletin has a new Lockheed Martin title for the same service bulletin: Lockheed Martin Service Bulletin 78-135, Revision 4, dated September 30, 1996. The appropriate revision level for the GE Service Bulletin is Revision 3, dated August 2, 1994. The GE and Lockheed Martin service bulletins are identical, and either may be used for accomplishment of the action described previously.
Note 4: The actions specified in Lockheed Martin Service Bulletin 78-1007, Revision 1, dated March 18, 1997; and Lockheed Martin Service Bulletin 78-1020, Revision 2, dated March 20, 1997; may be accomplished simultaneously in conjunction with Boeing Service Bulletin 767-78-0063 for accomplishment of the installation of the thrust reverser bracket and the thrust reverser lock. (Accomplishment of these two service bulletins together achieves the same results as Lockheed Martin Service Bulletin 78-135, Revision 4, and is acceptable for compliance with Boeing Service Bulletin 767-78-0063.)
(d) Perform a functional test to detect discrepancies of the cone brake of the center drive unit (CDU) on each thrust reverser, in accordance with Boeing Service Bulletin 767-78A0081, Revision 1, dated October 9, 1997, or Appendix 1 (including Figure 1), sections 1.A.(2), 2.A., 2.C., and 2.D of this AD. Accomplish the functional test at the time specified in paragraph (d)(1) or (d)(2) of this AD, as applicable.
(1) For airplanes on which the test required by paragraph (d) of AD 95-13-12 R1 has been accomplished prior to the effective date of this AD: Accomplish the functional test within 1,000 flight hours after the most recent test of the CDU cone brake performed in accordance with paragraph (d) of AD 95-13-12 R1, or within 650 flight hours after the effective date of this AD, whichever occurs later.
(2) For airplanes on which the test required by paragraph (d) of AD 95-13-12 R1 has NOT been accomplished prior to the effective date of this AD: Accomplish the functional test within 1,000 flight hours since the date of manufacture, or within 650 flight hours after the effective date of this AD, whichever occurs later.
(e) Repeat the functional test of the CDU cone brake specified in paragraph (d) of this AD at the time specified in paragraph (e)(1) or (e)(2) of this AD, as applicable.
(1) For Model 767 series airplanes, line numbers up to and including 474, equipped with thrust reversers that have not been modified in accordance with Boeing Service Bulletin 767-78-0063: Repeat the functional test of the CDU cone brake thereafter at intervals not to exceed 650 flight hours.
(2) For Model 767 series airplanes, line numbers 475 and subsequent; and Model 767 series airplanes equipped with thrust reversers that have been modified in accordance with Boeing Service Bulletin 767-78-0063: Repeat the functional test of the CDU cone brake thereafter at intervals not to exceed 1,000 flight hours.
(f) Within 1,000 flight hours after accomplishing the modification required by paragraph (c) of this AD or after the equivalent modification (Production Revision Record B11481-70) is incorporated in production, or within 1,000 flight hours after the effective date of this AD, whichever occurs later: Perform operational checks of the electro-mechanical brake in accordance with Appendix 1 (including Figure 1), sections 1.A.(1), 2.A., 2.B., and 2.D of this AD. Repeat the operational checks thereafter at intervals not to exceed 1,000 flight hours.
(g) If any functional test or operational check required by paragraph (d), (e), or (f) of this AD cannot be successfully performed, prior to further flight, repair in accordance with Boeing Service Bulletin 767-78A0081, Revision 1, dated October 9, 1997; or Appendix 1, section 2.B. and 2.C., of this AD; as applicable; and repeat the applicable test or check until successfully accomplished.
(h) Accomplishment of the modification required by paragraph (c) or installation of an equivalent modification (Production Revision Record B11481-70) in production, and accomplishment of periodic operational checks required by paragraphs (d), (e), and (f) of this AD, constitutes terminating action for the tests, inspections, and adjustments required by paragraph (a) of this AD.
(i)(1) An 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.
(2) Alternative methods of compliance, approved previously in accordance with AD 95-13-12, amendment 39-9292, are approved as alternative methods of compliance with this AD.
Note 5: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO.
