Electrical Power Supply System Failure

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Complete Electrical Failure


If complete electrical failure occurs because of loss of both generators, the APUs will continue to operate. If the APU's are not operating, the emergency battery must be energized to start the APUs. With both generators failed, the airplane can be landed. If complete electrical failure occurs because of failure of both APUs, the emergency battery switch [23, fig. 5-1] must be turned ON, so that the APUs can be restarted. If the APUs cannot be restarted, ejection is mandatory.



Generator Failure


If either APU or generator fails and cannot be reset, certain missions may be flown, dependent on ground control. If a failure of this type should occur, proceed as follows:


  1. No. 1 or No. 2 blower switch [10, fig. 5-9] – OFF. Operation of one equipment compartment blower at a time will substantially reduce the electrical load; however, operation of only one blower will appreciably shorten its life.


  1. Vent suit heater switch [6, fig. 5-4] – OFF.


  1. Pressure suit ventilation knob [5, fig. 5-4] – OFF.



As soon as the unique research portion of the flight is over, continue with the following steps:


  1. Instrumentation master switch [15, fig. 5-3] – OFF.


  1. Radar beacon switch [14, fig. 5-3] – OFF.


  1. Telemeter master, commutator and FM switches [18, 17, 8, fig. 5-3] – OFF.


  1. No. 1 and No. 2 blower switches [10, fig. 5-9] – BLOWER & LN2.



Generator Reset Procedure (APUs Running)


When a generator irregularity occurs, as shown by a generator failure light [20, 25, fig. 5-1] coming on, try to bring the generator back as follows:


  1. Generator switch [21, 26, fig. 5-1] – RESET momentarily; then ON. Generator-out light should go out and remain out if failure was temporary.


  1. Generator-out light [20, 25, fig. 5-1] – Check OFF.



Emergency Battery Operation


If failure of both APUs or both generators occurs, the emergency battery must be energized to power the battery bus. The battery bus supplies power for re­starting the APUs or to control the APUs:


  1. Emergency battery switch [23, fig. 5-1] – ON.