King Air C90GTi, Pilot Training Manual

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The vacuum line for the instruments is routed
t h r o u g h a s u c t i o n r e l i e f va l ve t h a t i s d e -
signed to admit into the system the amount
of air required to maintain suff icient vac-
uum for proper operation of the instruments.
A G Y RO S U C T I O N g a g e ( F i g u r e 9 - 3 ) ,
which is calibrated in inches Hg and is on
the copilot’s right subpanel, indicates in-
str ument vacuum.
CABIN DOOR SEAL
T h e e n t r a n c e d o o r t o t h e c a b i n a n d t h e
escape hatch uses air from the pneumatic
system to inflate the seals after the air plane
lifts off the g round. Pneumatic air is tapped
off the manifold downstream of the 18 psi
pressure regulator. The regulated air then
passes through a 4 psi regulator and to the
nor mally-open valve that is controlled by
the left landing gear safety switch. When
the air plane lifts off, the landing gear switch
opens the valve to the door and hatch seals,
and the seals inflate.
SURFACE DEICE
SYSTEM
The leading edges of the wings and horizon-
tal stabilizer are protected against an accu-
mulation of ice buildup. However, the winglets
on the C90GTx are not protected (Figure 9-
4). Inflatable boots attached to these surfaces
are inflated when necessar y by pneumatic
pressure to break away the ice accumulation,
and are deflated by vacuum. The vacuum is
always supplied while the boots are not in use
and are held tightly against the wing. Vacuum
pressure is overcome by pneumatic pressure
when the boots are inflated.
KING AIR C90GTi/C90GTx PILOT TRAINING MANUAL
9-4
FOR TRAINING PURPOSES ONLY
9
PNEUMA
TICS
Figure 9-3. Gyro Suction Gage
Figure 9-4. Surface Deice Boot Installation