TM 55-1510-215-10
transfer pumps), and one at the inertial separator air
(JP-4) or Commercial ASTM Type B fuels. Whenever
bypass duct (to drain fuel filter).
this
condition
occurs,
the
engine
operating
characteristics may change in that lower operating
g. Fuel Types. Approved fuel types are as follows:
temperature, slower acceleration, lower engine speed,
easier starting, and shorter range may be experienced.
(1) Army standard fuels. These are the Army-
The reverse is true when changing from F-40 (JP-4) fuel
designated primary fuels adopted for worldwide use, and
to F-44 (JP-5) or Commercial ASTM Type A-1 fuels.
are the only fuels available in the Army supply system.
Most commercial turbine engines will operate
satisfactorily on either kerosene or JP-4 type fuel.
(2) Alternate fuels. These are fuels which can
However, the difference in specific gravity may possibly
be used continuously when Army standard fuel is not
require fuel control adjustments; if so, the
available, without reduction of power output. Power
recommendations of the manufacturers of the engine
setting adjustments and increased maintenance may be
and airframe are to be followed.
required when an alternate fuel is used.
2-87. Servicing Oil System.
(3) Emergency fuel. These are fuels which
can be used if Army standard and alternate fuels are not
available. Their use is subject to a specific time limit.
CAUTION
h. Use of Fuel. Fuel is used as follows:
Do not mix MIL-L-23699 oil with MIL-
(1) Fuel limitations.
There is no special
L-7808 oil except in case of
limitation on the use of Army standard fuel, but certain
emergency. If it becomes necessary
limitations are imposed when Alternate or Emergency
to mix the oils, the applicable system
fuels are used. For the purpose of recording, fuel
shall be flushed within six hours and
mixtures shall be identified as to the major component of
filled with the proper oil.
the mixture, except when the mixture contains leaded
gasoline. A fuel mixture which contains over 10 percent
leaded gasoline shall be recorded as all leaded gasoline.
CAUTION
The use of any fuels other than standard will be entered
in the FAULTS/REMARKS column of DA Form 2408-13,
Aircraft Maintenance and Inspection Record, noting the
Make sure oil filler cap latch tab is
type of fuel, additives, and duration of operation.
pointed aft.
(2) Use of kerosene fuels.
The use of
An integral oil tank occupies the cavity formed
kerosene fuels (JP-5 type) in turbine engines dictates
between the accessory gearbox housing and the
the need for observance of special precautions. Both
compressor inlet case on the T74-CP-700 engine. The
ground starts and air restarts at low temperature may be
tanks have a total oil capacity of 2.3 gallons and features
more difficult due to low vapor pressure.
a calibrated oil dipstick and an oil drain plug. If engine
has been stationary for more than 12 hours, carry out a
(3) Mixing of fuels in aircraft tanks. When
motoring run (no ignition) before checking oil level.
changing from one type of authorized fuel to another, for
Avoid spilling oil. Any oil spilled must be removed
example JP-4 to JP-5, it is not necessary to drain the
immediately.
Use a cloth moistened in solvent to
aircraft fuel system before adding the new fuel.
remove oil. Overfilling may cause a discharge of oil
through the accessory gearbox breather until a
(4) Fuel specifications.
Fuels having the
satisfactory level is reached. Service oil system as
same NATO code number are interchangeable. Jet
follows.
fuels conforming to ASTM D-1655 specification may be
used when MIL-T-5624 fuels are not available. This
1. Open the upper rear cowling to gain access to
usually occurs during cross country flights where aircraft
the oil filler cap and dipstick.
using NATO F-44 (JP-5) are refueled with NATO F-40
2-77
