83-26-01 BRITISH AEROSPACE: Amendment 39-4785. Applies to Model HS 748 airplanes, certificated in all categories, for the series listed in the service bulletins below. To prevent the development of unsafe conditions, the following three actions are required, unless previously accomplished:
A. To prevent progression of cracks in the main landing gear inboard pivot brackets, part numbers 15F11365 and 16F11365, inspect the inboard pivot brackets for corrosion, loose bolts, and cracks, and repair if necessary in accordance with the Accomplishment Instructions of British Aerospace HS 748 Service Bulletin 57/59, dated October 1979, prior to accumulating 25,000 landings or within the next 750 landings after the effective date of this AD, whichever occurs later, and thereafter at intervals not exceeding 1,500 landings from the last inspection. If inboard pivot brackets are corroded to a depth greater than 0.060 inch, the operators of the aircraft must contact the manufacturer for repair instructions.
B. To detect cracks in the joints between the tailplane center torsion box and outer tailplanes, inspect and repair, if necessary, the tailplane front and rear spar joint plates and webs in accordance with the Accomplishment Instructions of British Aerospace Aircraft Group HS 748 Service Bulletin 55/19, Revision 1, dated September 1982, prior to the accumulation of 18,000 hours time in service or within the next 750 hours time in service after the effective date of this AD, whichever occurs later, and thereafter at intervals not to exceed 3,000 hours time in service.
C. Modify the aileron control quadrant assemblies on airplanes equipped with aileron control quadrant assemblies part numbers 1R4583 and 2R4583 in accordance with paragraph 2.B of British Aerospace Aircraft Group HS 748 Service Bulletin 27/75 dated April 4, 1978, prior to the accumulation of 12,000 hours time in service or within the next 750 hours time in service after the effective date ofthis AD, whichever occurs later.
D. Alternate means of compliance which provide an equivalent level of safety may be used when approved by the Manager, Seattle Aircraft Certification Office, FAA, Northwest Mountain Region.
E. Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base for the accomplishment of inspections and/or modifications required by this AD.
This amendment becomes effective January 30, 1984.