70-13-01 BRITISH AIRCRAFT CORPORATION: Amdt. 39-1012. Applies to Models BAC 1-11 200 and 400 series airplanes having razor socket supply transformer P/N RD.10590 installed.
To prevent overheating of the razor socket supply transformer when a non-compatible electrical appliance is connected into a razor socket, within the next 1500 hours' time in service after the effective date of this AD, unless already accomplished, accomplish either of the following:
(a) De-activate the razor sockets by disconnecting, insulating, and tying back the socket supply cable from the appropriate circuit breaker and fitting a locking clamp to the circuit breaker knob; or
(b) Modify the razor socket circuit to provide a 1/4 ampere fuse in the positive line of the rectified output of the transformer in accordance with British Aircraft Corporation Model BAC 1-11 Service Bulletin No. 25-PM4458 dated February 9, 1970, or a later ARB-approved issue, or an FAA-approved equivalent.
(British Aircraft Corporation Model BAC 1-11 Service Bulletin No. 25-A-PM4458 refers to this subject.)
This amendment becomes effective July 13, 1970.