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

How does the Auto Dilution Valve work?

Answer 2

PULLED-the flight crew will breathe cabin air, when oxygen supply is not required.
(Activates the oxygen saver mode manually)

PUSHED-the flight crew will breathe oxygen according to the position of the regulator knob.
(Deactivates the oxygen saver mode manually)

When the cabin pressure reaches an altitude between 6500 ft
and 9500 ft, or the mode selector is set to the EMGCY or 100%
position, the oxygen saver button is automatically pushed.

Question 3

When will the ADV auto dilution valve 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.

Question 6

What two things does the mask/mic switch do?

Answer 6

turns on the mic and turns on the speaker, speaker cannot be turned off

Question 7

Why do we go to ‘Crew Only’ on smoke evacuation?

Answer 7

So we don’t feed the fire with oxygen.