80-21-51 BRITISH AEROSPACE (FORMERLY VICKERS-ARMSTRONG AIRCRAFT LIMITED): Amendment 39-4205. Applies to all Viscount Model 744, 745D and 810 airplanes, certificated in all categories.
Compliance required as indicated, unless already accomplished.
To prevent failure of the elevator control system, accomplish the following:
(a) Before further flight, determine the time in service on spigot fitting P/N 70120-367. Replace each spigot fitting with a serviceable part in accordance with the following schedule, and thereafter continue to replace the spigot fittings at intervals not to exceed 3,000 hours time in service:
(1) If spigot fitting has 12,000 hours or more time in service since new, or the total time in service is unknown, replace before further flight.
(2) If spigot fitting has less than 12,000 but more than 3,000 hours time in service on the effective date of this AD:
(i) Before further flight, unless already accomplished, inspect forcracks using the magnetic flaw detection saturation method and 5X magnification in accordance with item 4 of the British Aerospace Weybridge Bristol Division Campaign Wire REF SS/749/V, dated September 5, 1980, or an FAA-approved equivalent. If any crack or cracks are found, replace spigot fitting before further flight.
(ii) If no cracks are found, replace spigot fitting within 300 hours time in service after the effective date of this AD, or prior to the accumulation of 12,000 hours time in service, whichever occurs first, except as provided in paragraph (a)(4) of this AD.
(3) If spigot fitting has 3,000 hours time in service or less on the effective date of this AD, replace prior to the accumulation of 3,000 hours time in service, or within 300 hours time in service, whichever occurs later.
(4) Spigot fittings with more than 3,000 hours time in service on the effective date of this AD must be replaced prior to September 15, 1981.
(b) Before further flight, unless already accomplished, inspect the spring servo tab operating mechanism for security by examining the inboard tab on the LH elevator and its attachment to the elevator together with connecting linkage through to "bellcrank" lever, P/N 70133-567, and its associated spigot fitting, P/N 70120-367, on the inner end of the LH elevator torque tube. In addition, the control circuit must be checked from this point through to the adjustment spring located on the inner end of the subject torque tube. If defects are found, repair as necessary and return to service.
(c) When replacing spigot fitting, P/N 70120-367, insure that the twin center bearing assembly in the control lever, P/N 70133-567, is free to move. If defects are found, repair as necessary and return to service.
(d) For Viscount Type 810, prior to the accumulation of 10,000 flights or within 50 hours time in service after the effective date of this AD, whichever occurs later, inspect the right and left handtailplane top root end fittings, P/N's 81018-227 and 81018-228, in accordance with British Aerospace Technique AL/MAT/3713, dated September 26, 1980, or an FAA-approved equivalent. Cracked fittings must be replaced prior to further flight.
(e) If an FAA-approved equivalent is used in complying with this AD, that equivalent must be approved by the Chief, Aircraft Certification Staff, FAA, Europe, Africa, and Middle East Office. Report defects found to the Chief, Aircraft Certification Staff, FAA, Europe, Africa and Middle East Office, c/o American Embassy, Brussels, Belgium. Reporting approved by the Office of Management and Budget OMB No. 04/R0174.
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 British Aerospace, Aircraft Group, Weybridge-Bristol Division, Brooklands Road, Weybridge, Surrey, England KT13 OSF. These documents may be examined at FAA Headquarters, Room 916, 800 Independence Avenue, SW., Washington, D.C. 20591.
This amendment becomes effective August 27, 1981, as to all persons except those persons to whom it was made immediately effective by telegraphic AD T80-21-51, issued October 2, 1980, which contained this amendment.