All systems on board an aircraft can be shut off for a number of reasons. In case of a power failure, the pilot must choose what functions are the most essentia

All systems on board an aircraft can be shut off for a number of reasons. In case of a power failure, the pilot must choose what functions are the most essential to the continued operation of the aircraft on the limited battery power remaining. A transponder may then become nonessential. Similarly, if it is faulty and is the cause of an electrical fire, power to the transponder must be able to be shut off.