The APU Control Box.
The APU Control Box, mounted in the left forward part
compartment, controls the operation of the APU (Figure 6).
PART C - PRELIMINARY STEPS TAKEN WHEN APU ENGINE
CRANKS BUT FAILS TO START
compression/ignition. If these requirements are not provided in the proper
amounts, the engine will either not run properly or not run at all.
either event, it is necessary to perform a systematic check to determine why
the engine does not start. When the APU engine cranks but fails to start,
use preliminary steps before troubleshooting the APU.
The application of
the preliminary steps saves time.
The preliminary steps outlined below
assist you to make a determination as to whether troubleshooting procedures
are or are not required.
When you decide that troubleshooting procedures
must be applied, follow the instruction in Part D, Troubleshooting the APU
Due to the locations of the APU in relation to the APU control box,
some of the preliminary steps may require the use of two persons.