AD 93-19-05

93-19-05 BOEING: Amendment 39-8703. Docket 92-NM-179-AD. Supersedes AD 89-26-04, Amendment 39-6423.

Applicability: Model 767 series airplanes, line positions 001 through 402, inclusive; certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

NOTE 1: Paragraph (a) of this AD restates the requirements of paragraph B. of AD 89-26-04. As allowed by the phrase, "unless accomplished previously," if the requirements of paragraph B. of AD 89-26-04 have been accomplished previously, paragraph (a) of this AD does not require that they be repeated.

To prevent uncommanded deployment of the slats and to ensure trailing edge flap shutdown protection and trailing edge flap alternate mode availability, accomplish the following:

(a) Within the next 25 days after December 27, 1989 (the effective date of AD 89- 26-04, amendment 39-6423), conduct a functional check of the leading edge slat long term shutoff control and the leadingedge inboard and outboard slat drive mechanical rigging in accordance with Boeing Alert Service Bulletin 767-27A0094, dated September 28, 1989.

(b) Within the next 25 days after December 27, 1989, conduct a functional check of the leading edge slat shutoff valve and the trailing edge flap drive bypass valve in accordance with Boeing Alert Service Bulletin 767-27A0094, dated September 28, 1989; or Revision 4, dated October 22, 1992. Repeat this functional check thereafter at intervals not to exceed 400 landings until the functional check required by paragraph (c) of this AD is accomplished.

NOTE 2: Accomplishment of the functional check prior to the effective date of this AD in accordance with any revision of Boeing Alert Service Bulletin 767-27A0094 prior to Revision 4, dated October 22, 1992, is considered acceptable for purposes of compliance with this paragraph.

(c) Within 4,000 hours time-in-service after the last functional check performed in accordance with paragraph (b) of this AD, conduct a functional check of the leading edge slat shutoff valve and the trailing edge flap drive bypass valve in accordance with Boeing Alert Service Bulletin 767-27A0094, Revision 4, dated October 22, 1992. Accomplishment of this functional check terminates the repetitive functional check requirements of paragraph (b) of this AD. Repeat this functional check thereafter at intervals not to exceed 4,000 hours time-in- service.

(d) Within 4,000 flight hours after the effective date of this AD, conduct a functional check of the leading edge slat long term shutoff control and the leading edge inboard and outboard slat drive mechanical rigging, in accordance with Boeing Alert Service Bulletin 767-27A0094, Revision 4, dated October 22, 1992. Repeat this functional check thereafter at intervals not to exceed 4,000 hours time-in-service.

(e) If any failed parts are detected by the functional checks required by paragraphs (a), (b), (c), or (d) of this AD, prior to further flight, replace the failed part in accordance with the Boeing 767 Maintenance Manual.

(f) Within 12,000 flight hours after the effective date of this AD, accomplish the requirements of paragraphs (f)(1) and (f)(2) of this AD. Accomplishment of these requirements constitutes terminating action for the repetitive functional checks required by paragraphs (b), (c), and (d) of this AD.

(1) Install a pressure switch and replace the rotary variable differential transformer (RVDT) and the flap/slat electronic unit (FSEU) in accordance with Boeing Service Bulletin 767-27-0108, Revision 1, October 1, 1992.

(2) Replace the bypass valve motor (trailing edge flaps, control valve module) in accordance with Boeing Service Bulletin 767-27-0096, dated April 23, 1992.

(g) 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.

NOTE 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO.

(h) Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate the airplane to a location where the requirements of this AD can be accomplished.

(i) The functional checks shall be done in accordance with Boeing Alert Service Bulletin 767-27A0094, dated September 28, 1989; and Boeing Alert Service Bulletin 767- 27A0094, Revision 4, dated October 22, 1992. The modifications shall be done in accordance with Boeing Service Bulletin 767-27-0108, Revision 1, October 1, 1992; and Boeing Service Bulletin 767-27-0096, dated April 23, 1992. 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 Federal Aviation Administration (FAA), Transport Airplane Directorate, Rules Docket, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

(j) This amendment becomes effective on November 24, 1993.