Avionics ventilation

Question 1

Where does the air come from for the avionics vent system?

Answer 1

Air recirculated from the cabin

Question 2

When the ditching pb is pressed, what position are the underfloor extract and ovbd extract valves in?

Answer 2

ovbd extract valve is closed, underfloor v/v is open

Question 3

How is a flow of air made available for pack bay vent on the ground and in flight?

Answer 3

On ground, a turbofan. In the air, a naca air inlet

Question 4

What happens when the extract pb is set to ovrd

Answer 4

underfloor extract valve closes, ovbd valve partly opens

Question 5

In flight, with extract pbs set to auto, what is the position of the underfloor and ovbd extract valves??

Answer 5

ovbd extract valve is closed, underfloor valve is open.