TM 1-1520-238-23
Change 8
E-23
E.11.
AUXILIARY POWER UNIT (APU) STORAGE PRESERVATION – continued
c. Preserve APU fuel system. Use lubricating oil (item 117, App F).
(1) Disconnect fuel inlet line from fuel nozzle (TM 1-2835-213-23).
(2) Connect tubing (item 213, App F) to fuel inlet line.
(3) Disconnect fuel inlet line from APU fuel control unit (para 15.20) and install protective cap
(TM 1-1500-204-23).
(4) Disconnect fuel inlet line to APU boost pump (para 10.108) and install protective cap (TM 1-1500-204-23).
(5) Connect tubing (item 213, App F) to fuel control unit inlet.
(6) Place free end of tubing (item 213, App F) into container of lubricating oil (item 117, App F).
(7) Apply external power – electrical (para 1.70). Use aircraft power unit.
(8) Apply external power – hydraulic (utility) (para 1.73). Use aircraft power unit.
(9) Motor APU until only oil is expended from fuel line.
(10) Remove external power – hydraulic (utility) (para 1.73).
(11) Remove external power – electrical (para 1.70).
(12) Install protective caps on disconnected ends of fuel nozzle, fuel lines, and APU fuel control unit
(TM 1-1500-204-23).
(13) Tag APU fuel control unit inlet elbow and APU START/RUN switch on right console with the following
caution message:
CAUTION
Fuel system has been preserved with lubricating oil (item 117, App F). Flushing is required before
placing helicopter in service.
d. Drain oil from APU (para 1.26).
e. Replace APU oil filter (TM 1-2835-213-23).
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