70-17-01 BRITISH AIRCRAFT CORPORATION: Amdt. 39-1061. Applies to Model BAC 1-11 Series 401 Type AK airplanes.
To prevent overheating of the heating elements fitted to the S8 and S9 right-hand and left-hand static vent plates located at Station 66, within the next 200 hours' time in service after the effective date of this AD, unless already accomplished, accomplish one of the following:
(a) Deactivate the static plate heaters in accordance with Part (B) of British Aircraft Corporation Model BAC 1-11 Service Bulletin No. 30-PM4306 dated November 28, 1969, or a later ARB-approved issue or an FAA-approved equivalent; or
(b) Modify the pitot/static plate heater circuit to provide a separate power supply for each circuit in accordance with Part (A) of British Aircraft Corporation Model BAC 1-11 Service Bulletin No. 4306 dated November 28, 1969, or a later ARB-approved issue or an FAA-approved equivalent.
This amendment becomes effective September 5, 1970.