PTM Ch. 12 Pressurization Flashcards
How is the airplane pressurized?
Controlling the amount of conditioned air that is allowed to exit the aircraft through the outflow valve
Normal Max cabin differential pressure
7 psi
This allows for sea level cabin altitude below:
16,800’
What is the only part of the aircraft that isn’t pressurized?
Nose compartment
When must the cabin be depressurized?
During takeoff and landing
The motive force for OPERATION of pressurization comes from:
Engine bleed air
How is the outflow valve opened?
Vacuum
How is the outflow valve closed?
Spring pressure
If the pressure exceeds what, the outflow valve will fully open.
7.25 psi
How else will the outflow valve open?
If negative pressure condition is present
What was installed to speed up outflow valve reaction time?
Pneumatic relay
What do you set the pressurization altitude to for take off and landing?
500’ AGL
What do you set the pressurization altitude to during cruise?
1000’ above cruise altitude
What is the cabin rate of climb?
A VSI for the cabin altitude in fpm.
On the cabin altitude what is the outer scale used for?
Cabin altitude
What is the inner scale on the cabin altitude for?
Differential pressure
Where is the dump valve located?
Left side of the forward pressure bulkhead
How is the dump valve opened?
Vacuum
How is the dump valve closed?
Spring pressure
If the outflow valve fails closed, the dump valve will open at what PSI?
7.3 +/- 0.1 psi
Upon landing what does the squat switch do to the dump valve?
Open it.
How else can the dump valve be opened?
Electrically with the CABIN PRESS switch
What is the CABIN PRESS switch that electrically opens the dump valve powered by?
Left essential bus transferable to the right
What does the DUMP switch do?
Bypasses the squat switch and applies vacuum to the dump valve, fully opening it.
