To prevent damage to the AGPU
(5) Ensure bypass/flush
AGPU hydraulic pump, the
RESERVOIR selector must always
be set to AGPU on completion of
Personnel are required to
use the aircraft intercom
Check the aircraft reservoir
communication system to
maintain voice communi-
cations between the person
(2) If overfilled move RETURN
BYPASS selector to BYPASS to drain. If
the level is low move the selector to
(3) When proper reservoir levels
(6) Apply external power to
are restored simultaneously switch both
the aircraft and establish voice
the RETURN BYPASS and OUTPUT to OFF.
(4) Open HIGH PRESSURE BLEED valve
1/4 turn. Hold PRESSURE switch (11) to
(7) Apply external
DECREASE position until the OUTPUT
aircraft (AH-64 only).
PRESSURE drops to 500 to 700 psig.
(8) Recheck the AGPU reser-
(5) Close HIGH PRESSURE BLEED
voir fill level gauge on the
hydraulic control panel to ensure
(6) Disconnect hoses, reinstall
the reservoir is full. Add fluid
all caps and plugs in stow in AGPU.
h. Flush Aircraft Flight Control
(9) Open AGPU dual hydraulic
service manifold drain valve and
Dual service manifold is
used on both single and
dual hydraulic systems.
(11) On the AGPU hydraulic
control panel set RETURN BYPASS
The AGPU must have been
selector to OFF and make sure
properly sampled and cleared for
Ensure the reservoir is
Flush hoses and connect AGPU
switch to ON.
Set OUTPUT switch
through e, above.
pressure in accordance with Table
Locate a clean 10-gallon or
Connect a hose to drain
connector on the AGPU dual service
decrease to between 1/2 and
1/3 full on the reservoir
opposite end of hose in drum.
level gauge. Do not allow
AGPU adapter hose can be used as the
the reservoir level to
drain hose by removing the quick
decrease below 1/3 full.
(5-7 gallons flushed)