85-12-06 BRITISH AEROSPACE VISCOUNT: Amendment 39-5078. Applies to Model 700 and 800 series airplanes, certificated in all categories, as indicated in each paragraph below. To prevent failure of certain components in the main undercarriage, and wing trailing edge member spar and liner assemblies, accomplish the following within the compliance time specified in each paragraph below, unless previously accomplished:
A. For all Model 800 series, pre-Modification F.1323 Standard, which are equipped with Dunlop AH.50961/2 Main Wheel Brake Units: Inspect, modify, and replace in accordance with Preliminary Technical Leaflet (PTL) No. 90 and Modification F.1794, both dated May 18, 1960, prior to the accumulation of 3,000 total landings. On those assemblies which have already achieved 2,750 landings, the requirements of PTL 90 and Modification F.1794 must be accomplished within 250 landings or 2 months, whichever occurs later, after the effective date of this AD.
B. For all Model700 and 800 series, inspect the top boom/liner assemblies for cracks between station 132.85 and station 138 on all Model 700 series in accordance with PTL 309, Issue 2 dated December 10, 1979, and all Model 800 series in accordance with PTL 178, Issue 2 dated December 10, 1979, prior to the accumulation of 27,500 total landings. On those assemblies which have already achieved 27,250 or more total landings, initial inspections must be accomplished within 250 landings or 2 months, whichever occurs later, after the effective date of this AD. Repeat inspections at intervals not exceeding 2,000 landings or 12 months, whichever is sooner.
C. Alternate means of compliance which provide an acceptable level of safety may be used when approved by the Manager, Seattle Aircraft Certification Office, FAA, Northwest Mountain Region.
D. 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 modifications required by this AD.
This amendment becomes effective July 15, 1985.