filler valve, filter, two check valves, and two
pressure gauges. The filler valve allows filling both
the canopy pneumatic reservoir and the emergency
landing gear reservoir from a single point. The
check valves prevent reverse flow when one
reservoir has a lower pressure than the other.
Canopy Switch
The canopy switch is actuated by the canopy
locking mechanism lock lockpin; the switch closes
when the canopy unlocks. This completes a
circuit to the canopy caution indicator light on
the pilot and NFO CAUTION ADVISORY
indicators. When the canopy locks, the switch
opens.
Auxiliary Pneumatic Reservoir
The auxiliary pneumatic reservoir, aft of
the canopy, has a 14.6-cubic-inch capacity.
It stores high-pressure dry nitrogen for un-
locking the canopy in the auxiliary mode.
The reservoir is serviced, through a filler
manifold, to 3,000 psi.
Auxiliary Pneumatic Reservoir
Filler Manifold
The auxiliary pneumatic reservoir filler
manifold is connected to the auxiliary pneumatic
reservoir. It consists of a nitrogen filler valve and
pressure gauge.
Auxiliary Pneumatic Reservoir
Relief Valve
The auxiliary pneumatic reservoir relief valve,
adjacent to the auxiliary pneumatic reservoir,
is connected to the reservoir outlet port.
It is a spring-loaded poppet valve that prevents
overpressurization of the auxiliary pneumatic
reservoir. Valve cracking pressure is 4,500 psi; full
flow occurs at 5,100 psi. The valve reseats when
the auxiliary pneumatic pressure drops to 4,100
psi.
Auxiliary Pressure Reducer
The auxiliary pressure reducer, located
downstream of the auxiliary pneumatic reservoir,
reduces pneumatic pressure (to 325 psi) applied
to the auxiliary unlock pneumatic release
valve.
Auxiliary Unlock Pneumatic
Release Valve
The auxiliary unlock pneumatic release valve,
aft of the canopy, is a lever-operated shutoff valve
that is connected by a cable-and-pulley assembly
to the canopy control handle in the pilot and NFO
stations. It is a two-position valve operated by an
eccentric cam mechanism and detented to main-
tain the open position. An internal vent releases
pneumatic pressure when the auxiliary mode is not
selected. When the auxiliary mode is selected to
unlock the canopy, the vent port is blocked to per-
mit pneumatic pressure application to the un-
lock shuttle valve. After each auxiliary mode
operation, the cam must be reset manually to
return the system to normal.
Unlock Shuttle Valve
The unlock shuttle valve, aft of the canopy,
is a three-port, pressure-operated valve. An in-
ternal spool is shuttled by pneumatic pressure at
either end of the valve housing to block one of
the two end inlet ports. When the canopy control
handle is moved to the OPEN position, pneumatic
pressure flows from the canopy pneumatic control
module, through the shuttle valve and the unlock
actuator restrictor, to the unlock side of the
canopy-lock pneumatic actuator. In the auxiliary
mode (AUX OPEN), auxiliary pneumatic
pressure shuttles the valve spool in the opposite
direction to route auxiliary pneumatic flow from
the auxiliary unlock release valve to the unlock
end of the canopy-lock pneumatic actuator.
EMERGENCY CANOPY
JETTISON SYSTEM
The emergency canopy jettison system
(fig. 2-3) jettisons the canopy clear of the cockpit
2-5
