92-27-15 DE HAVILLAND, INC.: Amendment 39-8450. Docket No. 92-NM-137-AD.
Applicability: All Model DHC-7 series airplanes, certificated in any category.
Compliance: Required as indicated, unless accomplished previously.
To prevent freezing of the elevator servo drum assembly, which could lead to an uncommanded pitch excursion with the autopilot engaged and reduced controllability of the aircraft, accomplish the following:
(a) Within 60 days after the effective date of this AD, install a water deflector onto the front spar of the vertical stabilizer, directly over the elevator servo assembly, Modification No. 7/2605, in accordance with paragraph III. of de Havilland Service Bulletin S.B. 7-55-10, dated October 25, 1991.
(b) 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, New York Aircraft Certification Office (ACO), FAA, Engine and Propeller Directorate. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, New York ACO.
NOTE: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the New York ACO.
(c) 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.
(d) The installation shall be done in accordance with de Havilland Service Bulletin S.B. 7-55-10, dated October 25, 1991. 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 de Havilland, Inc., Garratt Boulevard, Downsview, Ontario M3K 1Y5, Canada. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Engine and Propeller Directorate, New York Aircraft Certification Office, 181 South Franklin Avenue, Room 202, Valley Stream, New York 11581; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.
(e) This amendment becomes effective on February 8, 1993.