King Air C90GTi, Руководство по подготовке пилотов

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titude reaches the selected value, which may
happen before the air plane reaches the se-
lected altitude. Then as the airplane descends
to and reaches the cabin pressure altitude the
negative pressure relief function opens the
out-flow and safety valve poppets toward the
fully open position, thereby equalizing the
pressure inside and outside the pressure ves-
sel. As the air plane continues to descend
below the preselected cabin pressure altitude,
the cabin will be unpressurized and will fol-
low the airplane rate of descent to touchdown.
NOTE
As cabin ∆ P approaches zero dur-
ing a descent, the flapper door may
be forced open by ram air at air-
speeds above approximately 180
KIAS, causing a rapid depressur-
ization of the remaining cabin
∆ P
and an increase in air noise.
This opening of the flapper door
can be prevented by ensuring that
t h e c a b i n A l t i t u d e S e l e c t o r i s
properly set to 500 feet above the
l a n d i n g p r e s s u r e a l t i t u d e a n d
m a i n t a i n i n g s p e e d s b e l o w 1 8 0
KIAS in the landing patter n.
FLOW CONTROL UNIT
A flow control unit, mounted in each nacelle
on the forward side of the f irewall, controls
the bleed air from the engine for use in pres-
s u r i z a t i o n , h e a t i n g , a n d ve n t i l a t i o n . T h e
function of the flow control unit (Figure 12-
14) is to var y the flow and balance of bleed
air and ambient air to the cabin pressure ves-
sel. This is done by means of temperature
and pressure sensors and their related mod-
ulating valves.
KING AIR C90GTi/C90GTx PILOT TRAINING MANUAL
12-11
FOR TRAINING PURPOSES ONLY
12
PRESSURIZA
TION
LEGEND
COLD CONDITIONED AIR
HP BLEED AIR
AMBIENT AIR
TO OPEN
TO OPEN
EJECTOR
FLOW
CONTROL
ACTUATOR
N.O.
AMBIENT AIR
MODULATING
VALVE
AMBIENT
FLOW
CHECK
VALVE
BLEED
AIR FLOW
FILTER
EJECTOR
N.C.
SOLENOID
BYPASS
VALVE
AMBIENT
SENSE
ANEROID
PRESSURE
REGULATOR
PNUEMOSTAT
(PNEUMATIC
THERMOSTAT)
TO LH L.G.
SAFETY
SWITCH
N.O.
SOLENOID
VALVE
TO
CABIN
BYPASS
VALVE
N.C.
FIREWALL
SHUT--OFF
VALVE
AIR TO
AIR HEAT
EXCHANGER
TO OPEN
Figure 12-14. Flow Control Unit