Why is the GND CTL pushbutton selected to ON during preflight?
To record preflight activities in the cockpit
If the pushbutton was not selected ON, how would the CVR system work in automatic mode?
On the ground during the first 5 minutes after the aircraft electrical network is energized
* On the ground after the first engine start
* In flight (whether the engines are running or not)
* On the ground, it is stopped automatically 5 minutes after the last engine shutdown provided the CVR jack is not used.
What allows the cabin PAs to be recorded?
ACP 3 PA volume knob out and set at or above the medium range