TM 1-1520-238-10
2-88
Change 8
WARNING
When opening anti-syphoning device on
external tank flapper valve, extreme care
should be exercised when releasing air
pressure to preclude venting of fuel
overboard through filler neck.
NOTE
Use of JP–4 is prohibited during auxiliary
tank operation above 80 F ambient.
External fuel transfer is prohibited below
minimum safe single engine airspeed.
Internal fuel transfer is prohibited during
external fuel transfer.
i. Refueling of External Auxiliary Tanks.
The ex-
ternal auxiliary tanks are gravity-filled through filler recep-
tacles. Remove the gravity filler caps and service the aux-
iliary tanks to the ”AH–64 Fill line” marked on the flapper
valve inlet to the tank.
j. Fuel Sump Drains.
Two fuel sump drains (detail
K, fig 2-45), one for each tank, are located on the under-
side of the fuselage. They are used to drain fuel and check
for fuel contamination. To actuate, press the plunger. Hold
until sufficient fuel has been drained. The auxiliary fuel
tanks also contain fuel drains. To actuate the auxiliary fuel
tank drain valve, insert a phillips head screwdriver, push
inward while twisting clockwise until sufficient fuel has
been drained. Then reverse to stop fuel flow.
2.54.3 Oil System Servicing.
a. Oil Types.
Oils are classified as primary, com-
mercial equivalent, or emergency. Commercial equivalent
oils are listed in table 2-9. There are no emergency oils
authorized.
b. Nose Gearbox Servicing.
The nose gearboxes
are mounted on the front of each engine. When the oil falls
below the proper level (fig 2-45), service with oil (table
2-7).
c. Main Transmission Servicing.
Access to the oil
filler cap and the right sump oil level sight gage are
through the transmission access panel on the right side of
the fuselage (fig 2-2). The left sump oil level sight gage
can be viewed through the transmission access door on
the left side of the fuselage (fig 2-2). When the oil falls be-
low the proper level, either side, (fig 2-45), service with oil
(table 2-7).
CAUTION
Before beginning an extended flight with
auxiliary fuel tanks installed, engine oil
tanks will be filled to the ‘‘FULL” point on
the sight glass.
d. Engine Servicing.
The engine oil tank is located
in the engine frame. It is serviced through a gravity filler
port. An oil level sight gage is located near the gravity filler
port. When the oil falls below the proper level (fig 2-45),
service with oil (table 2-7).
e. APU Servicing.
The APU oil filler cap and oil lev-
el sight gage are located on the oil reservoir on the APU
gearbox. The sight gage can be viewed through an ac-
cess panel under the No. 2 engine. When the oil falls be-
low the proper level (fig 2-45), service with oil (table 2-7).
f. Hydraulic System Servicing.
The hydraulic
system should only be serviced (fig 2-45) with approved
fluids from table 2-7. Detailed hydraulic system servicing
instructions are in TM 1-1520-238-23.
