TM 9-6115-664-13&P
Section III. TROUBLESHOOTING
5-5. GENERAL.
This section contains direct support level troubleshooting information and tests for the APU. Troubleshooting
logic trees will aide in locating and correcting APU malfunctions. Each malfunction or trouble symptom is addressed and
is followed by a series of inspections or tests necessary to determine the probable cause and corrective action.
5-6. TROUBLESHOOTING.
a.
This manual can not list all possible malfunctions that may occur, all tests or inspections that may be performed,
or all corrective actions for each malfunction. Only those checks and tests authorized for the direct support level are
covered. If a malfunction is not listed, or is not remedied by corrective actions, notify personnel at a higher maintenance
level.
b.
Refer to the system electrical schematic (Figure FO-1) and wiring diagrams for assistance in troubleshooting
electrical components.
c.
Refer to Table 5-1, Malfunction Index, for determining applicable troubleshooting procedure.
Table 5-1. Malfunction Index
Table
Engine will not crank
5-2
Engine starts but fires intermittently or dies
5-3
Engine stops suddenly
5-4
Engine speed fluctuates
5-5
Engine hammers or knocks
5-6
Engine emits black smoke
5-7
5-3
