TM 1-1520-238-T-7
10–14
10–2.
LOCATION AND DESCRIPTION OF MAJOR COMPONENTS (cont)
10–2
d. Nitrogen Inerting System.
The nitrogen inerting system (fig. 10–4) consists of the nitrogen inerting unit
(NIU), the NITROGEN INERT MONITOR indicator and associated lines and fittings.
(1) NIU.
The NIU, located in the ammunition bay, utilizes pressurized air from the pressurized air
manifold and purges about 70% of the oxygen present. This air is then regulated into the aft fuel cell and onward
into the forward fuel cell.
(2) NITROGEN INERT MONITOR Indicator.
The NITROGEN INERT MONITOR indicator, located on the
aft avionics bay, displays normal system operation or system failure. It also provides a PRESS TO TEST
pushbutton for simulated system testing.
e. Gravity Refueling/Defueling System.
The gravity refueling/defueling system (fig. 10–5) consists of the
gravity filler ports is located on the right side of the fuselage. The gravity filler port consists of a cap assembly that
provides access to the gravity filler port, a gravity filler neck which provides an attachment point for the cap
assembly, and a refuel/defuel check valve which has a flapper valve (installed within the valve housing) that is
spring-loaded to the closed position. The flapper valve provides a means of sealing the gravity port to allow for
pressurizing the fuel cell with nitrogen.
M70-289A
GRAVITY
FILLER
NECK
CAP
ASSEMBLY
GRAVITY FUELING
REFUEL/DEFUEL
CHECK V ALVE
REFUEL/DEFUEL
CHECK V ALVE
CAP
ASSEMBLY
Figure 10–5.
Gravity Refueling/Defueling Major Component Location
f. Pressure Refueling/Defueling System.
The pressure refueling/defueling system (fig. 10–6) consists of
the refueling panel, the pressure refueling/defueling manifold, the fuel transfer (refuel) valve, the fuel level control
valve, the air/vent pressure relief valve, and the fuel vent shutoff valve.
(1) Refueling Panel.
The refueling panel, located on the right side of the fuselage, provides a means of
controlling refuel operations and monitoring fuel quantity during refueling, and allows the crew to pre-check
automatic fuel shutoff. To allow refueling operations without having to gain access to the crew station, power is
supplied by the battery to the FUEL QTY indicator switch and REFUEL VALVE switch.
