TM 1-1520-238-23
Change 2
1-252.3
1.75.
APU OPERATING INSTRUCTIONS – USING EXTERNAL POWER – continued
aa. Start APU.
(1) On APU fire test panel (12), hold START/
RUN switch (16) to RUN for 1 or 2 seconds,
then to START for 1 or 2 seconds.
(2) Release switch (16).
NOTE
APU is hydraulically started. If it does
not start, hydraulic accumulator pres-
sure may be too low.
When the APU turbine rotor reaches
95% or greater of normal revolutions
per minute (rpm), the APU ON indica-
tor on the pilot caution/warning panel
lights.
APU FAIL indicator on the caution/
warning panel remains lighted until
APU oil pressure reaches normal op-
erating pressure.
ab. Verify APU ON indicator light (17) is lighted on
pilot caution/warning panel (18).
ac. Set BATT/EXT PWR switch (9) on ELEC PWR
panel (10) to BATT.
ad. Turn on two generators.
(1) Set GEN 1 switch (19) to TEST.
(2) Verify GEN 1 light (20) on pilot caution/warn-
ing panel (18) is not lighted.
(3) Set GEN 2 switch (21) to TEST.
(4) Verify GEN 2 light (22) on pilot caution/warn-
ing panel (18) is not lighted.
(5) Set switches (19) and (21) to GEN 1 and
GEN 2.
(6) Verify GEN 1 light (20) and GEN 2 light (22)
are not lighted.
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PRI
RES
M04-1868-11A
16
12
9
10
22
20
19
21
18
17
M04-1868-12A
