Pressurisation

Question 1

What is the flow of air for pressurisation system?

Answer 1

Comes from the bleed air system (10th stage compressor) through the air con system into the aircraft.

Question 2

What does the outflow valve do and what controls it?

Answer 2

Outflow valve is a butterfly valve that is controlled by the cabin pressure controller operates to let air out to maintain the desired pressurisation schedule.

Question 3

What do the various switch positions do on the pressurisation panel?
1) AUTO
2) No Press
3) Constant Alt
4) AUX VEnt

Answer 3

1) Auto commands the CPCV to operate the outflow valve in such a way to maintain a preset schedule as determine in the flight manual.
2) No press will descend the cabin at whatever the rate is selected on the auto rate selector
3) Constant alt will keep the altitude the same dpeneding on what is set on the constant alt tab
4) aux vent will descend the cabin at 3000 fpm, turn both packs off and open ram inlet and outlet valves.

Question 4

What does the Emergency Depressurisation do?

Answer 4

Electrically commands the safety valve to open and cabin will descent at an uncontrollable rate.

Question 5

What is other way to descend the cabin?

Answer 5

Pulling the emergency depressurization handle which will open the aft escape hatch