Pressurization

Question 1

How does the aircraft depressurize after landing?

Answer 1

On the ground, a Residual Pressure Control Unit (RPCU) automatically opens the outflow valve and depressurizes the aircraft when:
* Both CPCs are failed or MAN mode is selected, and
* All engines are shut down, or all ADIRUs indicate an airspeed below 100 knots.

In the MAN mode, the outflow valve will not open automatically at touchdown.

Question 2

When do the safety valves open?

Answer 2

The safety valves will open when cabin pressure exceeds 8.6 PSI, or is 1 PSI below ambient.

Question 3

The six pressurization modes are:

Answer 3

• Ground
• Takeoff
• Climb
• Cruise
• Descent
• Abort

Question 4

One click of the MAN V/S CTL switch is worth approximately how much of cabin altitude change?

Answer 4

Approximately 50 FPM

Question 5

In normal operations, when would the DITCHING pb be used?

Answer 5

During deicing

Question 6

What does the DITCHING pb close?

Answer 6

POE A:
* Pack Flow Control Valves
* Outflow Valve
* Emergency Ram Air Inlet
* Avionics Inlet and Outlet