King Air C90GTi, Pilot Training Manual

Page: 248 / 557

UNPRESSURIZED
VENTILATION
Fresh-air ventilation is provided from two
sources. One source, which is available dur-
ing both the pressurized and the unpressur-
ized flight, is the bleed-air heating system.
This air mixes with recirculated cabin air
and enters the cockpit through glareshield
“eyeball” outlets (Figure 11-8) and the cabin
through the floor registers (Figure 11-9).
The volume of air from the floor registers is
regulated by using the cabin air control knob
located on the copilot’s subpanel.
T h e s e c o n d s o u r c e o f f r e s h a i r, wh i c h i s
ava i l a bl e d u r i n g t h e u n p r e s s u r i z e d f l i g h t
only, is ambient air obtained from a ram-air
scoop (Figure 11-10) on the nose (left side)
of the air plane. During pressurized opera-
tion, an electromagnet, in addition to cabin
p r e s s u r e , f o r c e s t h e r a m - a i r f l a p p e r d o o r
closed. During unpressurized flight, ram air
enters the evaporator plenum through the
r a m - a i r d o o r wh e n t h e e l e c t r o m a g n e t r e -
leases. Recirculated cabin air forced into
the evaporator plenum by a blower, mixes
with ram air from outside, is ducted around
the electric heater and mixing plenum and
into the ceiling-outlet duct. Air ducted to
e a c h i n d iv i d u a l c a b i n ( Fi g u r e 1 1 - 1 1 ) o r
cockpit (Figure 11-12) ceiling eyeball out-
let can be directionally controlled by mov-
i n g t h e e ye b a l l i n t h e s o c k e t . Vo l u m e i s
regulated by twisting the outlet to open or
close the outlet.
KING AIR C90GTi/C90GTx PILOT TRAINING MANUAL
11-5
FOR TRAINING PURPOSES ONLY
11
AIR
CONDITIONING
Figure 11-8. Glareshield “Eyeball” Outlets
Figure 11-9. Cabin Floor Outlets
TO CABIN
CEILING OUTLETS
ELECTRIC HEATER
PRESSURE BULKHEAD
MIXING
PLENUM
COCKPIT
CEILING
OUTLETS
VENT
BLOWER
RAM AIR
SCOOP
AIR PLENUM
Figure 11-10. Fresh Air Source
(Unpressurized Mode)
Figure 11-11. Cabin “Eyeball” Outlets