plug is called a safety plug. The relief valve relieves
the excess pressure in the container instead of
completely emptying the container.
Some larger aircraft use more than one fire
extinguishing agent container to direct the agent
to several points within an area. With cockpit
switches set at various positions, the agent can be
released through specific discharge outlets; and
if the fire persists, the switch positions can be
changed to release agent from a second container
to different discharge outlets within the same area.
The fire extinguishing system of the P-3 air-
craft is an example of this type of system. The
containers used in the P-3 system are also
equipped with two-valve (bonnet) assemblies for
discharging the container; however, only one
assembly is fired at any one time to discharge the
container. This dual arrangement provides a
secondary means of discharging a cylinder in the
event a cartridge fails for any reason to fire and
discharge the container.
Maintenance of the CF3Br fire extinguishing
system at the organizational level of maintenance
consists of replacement of faulty components
and discharged or below pressure containers,
maintenance of associated plumbing, and per-
forming operational checks.
Containers should be replaced when the
pressure falls below that indicated on the
container or in the applicable MIM. Each
container has a pressure indicating gage.
Suspected leakage in system plumbing requires
disconnection of the container(s) and pressure
leakage testing of all lines by using nitrogen
pressure and a leakage tester. The leakage tester
measures pressure drop over a specified period of
time, as outlined in the MIM.
The operational checkout of the fire ex-
tinguishing system, primarily a checkout of
electrical circuitry such as wiring continuity
checks, proper switch operation, etc., is per-
formed by personnel of the AE rating.
PROTECTION UTILITY SYSTEMS
Learning Objective: Recognize the purpose
of the thermal radiation protection system.
Naval aircraft used for special weapons
delivery have means of protecting the pilot and
crew members from the effects of heat and light
that such weapons emit. Several of the Navy
attack aircraft are equipped with a thermal
radiation protection system and flak protection
The A-6, for example, can be equipped with
radiation enclosures for the windshield and
canopy. These enclosures shield off the see-
through portions of the cockpit, which gives the
flight crew protection from the extreme heat and
light created by a special weapons delivery.
The radiation shields consist of fixed and
sliding fiber glass panels mounted on each side
of the canopy. The sliding panels are equipped
with rollers and suspended on a system of tracks
between the fixed side panels and the canopy
center overhead spline structure.
The sliding panels for each side of the
canopy move independently of each other and
are manually positioned by the pilot or bombar-
dier/navigator. The shield is closed by pulling the
forward sliding panel towards the canopy forward
arch. The forward panel is equipped with a lip,
which engages on the lip of the aft sliding panel,
drawing it forward at the same time.
The sliding panels will automatically lock in
one of three positions; open, closed, or half open,
as desired. A latch handle on each forward sliding
panel releases the detent pins, unlocking the
If the panels are closed and ejection becomes
necessary, it may be initiated through the closed
The windshield curtain is a fiber glass cloth
assembly with an aluminized coating. It is fastened
between the instrument panel glare shield and the
windshield bow structure to close off the entire
windshield area. Springs pull the windshield
curtain down flat on the glare shield for stowage
when the curtain is unzipped.
Flak curtains, similar to the canopy curtain,
are mounted beside the pilot and bombardier/
navigator foot area, cockpit side area, and along
the lower portion of the canopy. They provide a
limited measure of protection from flak and small
arms fire when making low-level attacks on enemy
The canopy-mounted curtain is a sandwich-
type pad constructed on vinyl-coated glass cloth
with a nylon center. The cockpit area side panels
are basically of the same construction with the
outboard vinyl coating deleted. The foot guard
panel is constructed of a metal plate with a nylon
curtain riveted to the outboard side. Installation