T-45A UJPT, E2-C2, ADV, & IUT Eng-17
ECS/Pressurization System & OBOGS
11. Ram air ventilation
Overlay 11
Ram Air
a.
Inlet/outlet valves operated by air
pressure from canopy seal system
b.
Admits outside air into forward cockpit
c.
Expels cabin air through ram air outlet
valve in aft cockpit
d.
Controlled automatically via WOW
switch
(1) Ground (weight-on-wheels):
opens ram air valves automatically
on touchdown when air
conditioning system switch is in
NORMAL, DEFOG, or MAX
DEFOG position
(2) Airborne (weight-off-wheels): with
air conditioning set to OFF, ram air
valves open, providing emergency
ventilation
B.
Cockpit pressurization system
Sg 2, fr 3
(3 overlays)
1.
General
a.
Pressurization commences with weight
off wheels and increases linearly, with
altitude, until attaining full differential
pressure of 4 psi at 40,000 ft MSL
b.
Cabin altitude may be as much as
COCKPIT PRESSURIZATION SYSTEM
2,000 ft below aircraft altitude from
MSL up to an aircraft altitude of
5,000 ft
c.
Provides signal to CABIN ALT warning
light if cockpit altitude exceeds 24,500
+/- 500 ft MSL
(8-03) Original
Page 17-7
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