73-12-12 BRITISH AIRCRAFT CORPORATION: Amdt. 39-1661. Applies to Viscount Series 810 airplanes.
Compliance is required as indicated.
To prevent a possible restriction in a power plant fire extinguisher pipe accomplish the following:
Within the next 500 hours' time in service after the effective date of this AD, unless already accomplished within 5 years prior to the effective date of this AD, and thereafter at intervals not to exceed 5 years from the last replacement, replace the rubber seal sleeves P/N FRS.-F-Series 1, installed in the power plant fire extinguisher system in the pipe connector assembly located at the engine fire-proof bulkhead, with seal sleeves of the same part number.
(BAC Alert Preliminary Technical Leaflet No. 149, Issue 1, dated July 30, 1971, covers this same subject).
This Amendment becomes effective July 6, 1973.