Question id 147 - Aircraft General Knowledge - Airframe, Systems, Powerplant - ATPL - Airline Transport Pilot license

The cabin air mass flow control inlet valve(s).
Delivering a substantially constant flow of air into the cabin and controlling the outflow.
The cabin air re-circulation system.
Controlling the flow of air into the cabin with constant outflow.

Training tests and timed exam simulations ATPL - Airline Transport Pilot license