Pressurization

Question 1

What are the max pressure differentials for the two safety valves?

Answer 1

+8.6psi and -1.0psi

Question 2

How is pressurization controlled?

Answer 2

Two Pressurization Controllers and a backup manual controller

Question 3

What does the Residual Pressure Control Unit do? (A320 only)

Answer 3

Automatically depressurizes in case of abnormal residual pressure on the ground.

Activates if (all conditions):
The outflow valve does not fully open
Both CPCs fail or manual mode
AC on the ground
Engines are shutdown or <100knots

Question 4

What are the inputs to the Pressure Controllers?

Answer 4

FMS, LGCIUs, ADIRs and throttle position

Question 5

When would you have to set the landing elevation?

Answer 5

Destination airport is not in the FMS database

OR

Both FMGCs fail

Question 6

What does the DITCHING pb close?

Answer 6

Outflow valve (if not set to MAN)
Emergency Ram Air Inlet
Avionics ventilation inlet and extract valves
Pack flow control valves
Forward cargo isolation valves

Question 7

What happens during takeoff?

Answer 7

When TOGO power is set, the controller starts cabin pressure climb at 400fpm until delta P is 0.1psi. Aborted takeoffs revert to ground mode.

Question 8

When will the pressurization system enter Abort mode?

Answer 8

Below 8000’
less than normal climb or
descent >200fpm for 30 seconds

Pressure reset to +0.1psi until climb re-initiated

Question 9

What is the max delta presurization?

Answer 9

8psi

Question 10

What is normal rate of cabin decent?

Answer 10

-750fpm, after touchdown it continues at -500fpm

Question 11

When does the pressurization controller switch to the other controller?

Answer 11

After each landing

Question 12

When in MAN mode, what is the target cabin VSI?

Answer 12

500fpm