King Air C90GTi, Руководство по подготовке пилотов

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PRESSURIZATION
SYSTEM
The pressurization system (Figure 12-1) is
designed to provide a cabin environment with
suff icient oxygen for normal breathing, re-
gardless of the airplane altitude, up to its de-
sign ceiling. As the airplane altitude increases,
the outside ambient air pressure decreases
until, at approximately 12,500 feet, it cannot
support normal respiration. The pressuriza-
tion system maintains a proportionally lower
inside cabin altitude. The pressure differen-
tial between the inside cabin pressure and the
outside ambient air pressure is measured in
pounds per square inch.
As the cabin altitude char t shows (Figure
12-2), whenever cabin altitude and air plane
altitude are the same, no pressure differ-
ential exists. Whenever cabin pressure is
the g reater of the two, pressure differential
is a positive number. If cabin pressure is
l e s s t h a n t h a t o f t h e o u t s i d e a m b i e n t a i r,
pressure differential is a negative number.
Maximum differential is def ined as a mea-
sure of the highest positive differential pres-
s u r e t h e a i r p l a n e s t r u c t u r e c a n s a f e l y
withstand for an extended period of time.
T h e K i n g A i r C 9 0 G Ti a n d C 9 0 G T x ,
equipped with PT6A-135A engines main-
tain a 5.0 ±0.1 psi differential and provides
a cabin pressure altitude of approximately
6,000 feet at an air plane altitude of 20,000
KING AIR C90GTi/C90GTx PILOT TRAINING MANUAL
12-3
FOR TRAINING PURPOSES ONLY
12
PRESSURIZA
TION
0
0
5000
5000
10,000
10,000
15,000
CABIN ALTITUDE – FEET
AIRPLANE ALTITUDE – FEET
ALTITUDE WARNING
15,000
20,000
20,000
25,000
25,000
30,000
30,000
35,000
35,000
EXAMPLE:
AIRPLANE ALTITUDE . . . . . . . . . . . . . . . . 20,000 FT
CABIN DIFFERENTIAL PRESSURE . . . . . 4.0 PSI
CABIN ALTITUDE . . . . . . . . . . . . . . . . . . . . 8500 FT
CABIN DIFFERENTIAL PRESSURE ~ PSI
Figure 12-2. Cabin Altitude for Various Airplane Altitudes Graph