81-06-03 SHORT BROTHERS LIMITED: Amendment 39-4057. Applies to Model SC-7 Series 3 airplanes, certificated in all categories, which have an autopilot installed.
Compliance is required within the next 50 hours time in service after the effective date of this AD, unless already accomplished.
To prevent aileron autopilot servo control cable breakage and possible loss of control of the airplane, accomplish the following:
(a) Inspect the aileron autopilot servo control cable for proper positioning on the guide pulley, for integrity, and for evidence of damage in the vicinity of the guide pulleys at station 226 in accordance with paragraphs 2.A.1, 2, and 3 of Shorts Service Bulletin 22-A59, dated May 21, 1979 (hereinafter referred to as the service bulletin), or an FAA-approved equivalent.
(b) If as a result of the inspection required in paragraph (a) of this AD:
(1) A damaged cable is found, replace the cable and accomplish paragraphs 2.A.4, 5, and 6 of the service bulletin, or an FAA-approved equivalent.
(2) An improperly positioned cable is found, reposition the cable after verification that no damage to the cable has occurred, and accomplish paragraph (d) of this AD.
(c) Determine the clearance between the cable guard and the outer rim of the pulley at station 226. If the clearance exceeds 0.029 inches, reposition the guard in accordance with paragraph 2.A.4 of the service bulletin, or an FAA-approved equivalent, and accomplish paragraph (d) of this AD.
(d) Check the aileron servo control cable for correct tension in accordance with paragraph 2.A.5 of the service bulletin, or an FAA-approved equivalent.
(e) If an equivalent means of compliance is used in complying with this AD, that equivalent must be approved by the Chief, Aircraft Certification Staff, AEU-100, Federal Aviation Administration, Europe, Africa, and Middle East Office, Brussels, Belgium.
The manufacturer's specifications and procedures identified and described in this directive are incorporated herein and made a part hereof pursuant to 5 U.S.C. 552(a)(1). All persons affected by this directive who have not already received these documents from the manufacturer may obtain copies upon request to Short Brothers Limited, P.O. Box 241, Airport Road, Belfast BT3 9DZ, Ireland, Attention: Product Support Manager. These documents may be examined at FAA Headquarters, Room 916, 800 Independence Avenue, S.W., Washington, DC.
This amendment becomes effective March 19, 1981.