Pressurization/Oxygen

Question 1

What are the three positions of the oxygen supply control knob and their functions?

Answer 1

CREW ONLY: disables automatic deployment of passenger oxygen masks.
PAX AUTO: enables automatic deployment of passenger oxygen masks
when cabin pressure altitude is above 14700 ft (+300/-300 ft), if the OXYGEN
SUPPLY handle is pushed.
PAX OVRD: deploys the passenger oxygen masks regardless of
cabin altitude, if the OXYGEN SUPPLY handle is pushed.

Question 2

What is the purpose of the Auto Dilution Valve?

Answer 2

When pulled, the flight crew will breathe cabin air, when oxygen supply is not required. When pushed, the flight crew will breathe oxygen according to the position of the regulator knob.

Question 3

When will the ADV automatically close?

Answer 3

In case of cabin decompression. Also, the ADV is capable of closing automatically
even without cabin decompression. (Normally, cabin pressure
altitudes from 8300 to 10000 ft cause the valve to close).

Question 4

When do the passenger oxygen masks automatically deploy?

Answer 4

14700 ft (+300/-300 ft).

Question 5

What does a “CAB ALTITUDE HI” CAS message indicate?

Answer 5

Cabin altitude is 10,000 ft or higher.