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95-21-14 DE HAVILLAND: Amendment 39-9401; Docket No. 91-CE-46-AD. Supersedes AD 83-18-03, Amendment 39-4719.
Applicability: Models DHC-6-1, DHC-6-100, DHC-6-200 and DHC-300 airplanes (serial numbers 1 to 810), certificated in any category, that do not have Modification 6/1799 incorporated in accordance with the ACCOMPLISHMENT INSTRUCTIONS, Replacement, section of de Havilland Service Bulletin (SB) No. 6/421, Revision B, dated November 11, 1983.
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 (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 request should include specific proposed actions to address it.
Compliance: Required as indicated in the body of this AD, unless already accomplished.
To prevent tailplane failure caused by cracks in either the outboard hinge arm or the hinge plate, which, if not detected and corrected, could result in loss of control of the airplane, accomplish the following:
(a) Within the next 50 hours time-in-service (TIS) after the effective date of this AD or within the next 1,200 hours TIS after the last inspection accomplished in accordance with superseded AD 83-18-03, Amendment 39-4719, whichever occurs later, inspect the tailplane outboard hinge arm assembly for cracks in accordance with the ACCOMPLISHMENT INSTRUCTIONS, Inspection, section of de Havilland SB No. 6/421, Revision B, dated November 11, 1983.
(1) If cracks are not found, reinspect every 1,200 hours TIS until Modification 6/1799 (tailplane outboard hinge arm and tailplane hinge plate) is installed as required by paragraph (b) of this AD.
(2) If cracks are found, prior to further flight, replace the tailplane outboard hinge arm assembly with Modification 6/1799 in accordance with the ACCOMPLISHMENT INSTRUCTIONS, Replacement, section of de Havilland SB No. 6/421, Revision B, dated November 11, 1983.
(b) Within 2,400 hours TIS after the effective date of this AD, replace the tailplane outboard hinge arm assembly with Modification 6/1799 in accordance with the ACCOMPLISHMENT INSTRUCTIONS, Replacement, section of de Havilland SB No. 6/421, Revision B, dated November 11, 1983, unless already accomplished in accordance with paragraph (a)(2) of this AD.
(c) Compliance with paragraph (a)(2) or (b) of this AD is considered terminating action for the inspection requirements of this AD.
(d) Special 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.
(e) An alternative method of compliance or adjustment of the initial or repetitive compliance times that provides an equivalent level of safety may be approved by the Manager, New York Aircraft Certification Office (ACO), FAA, 10 Fifth Street, 3rd Floor, Valley Stream, New York 11581. The request shall be forwarded through an appropriate FAA Maintenance Inspector, who may add comments and then send it to the Manager, New York ACO.
NOTE 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the New York ACO.
(f) The inspections and modification required by this AD shall be done in accordance with de Havilland Service Bulletin No. 6/421, Revision B, dated November 11, 1983. This incorporation by reference was approved bythe Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from de Havilland, Inc., 123 Garratt Boulevard, Downsview, Ontario M3K 1Y5 Canada. Copies may be inspected at the FAA, Central Region, Office of the Assistant Chief Counsel, Room 1558, 601 E. 12th Street, Kansas City, Missouri, or at the Office of the Federal Register, 800 North Capitol Street, NW., 7th Floor, suite 700, Washington, DC.
(g) This amendment (39-9401) supersedes AD 83-18-03, Amendment 39-4719.
(h) This amendment becomes effective on December 4, 1995.
