Taxi to Runway
The phase is activated once the Gate Departure announcement has been made. The announcement is usually made when you release the parking brakes.
The phase is activated in different ways. If you have the Prepare for Takeoff call configured to play before or after the takeoff checklists, the phase is activated when the Prepare for Takeoff call is made. Otherwise, the program does its best to ascertain that you’ve finished taxiing.
The phase is activated the moment your wheels leave the ground.
The phase is activated as you pass 3000 ft.
The phase is activated when you descend below a given triggering height. If your highest altitude was less than 12000 ft, the triggering height is 20% lower than your highest altitude. If you went to an altitude higher than 12000ft, the triggering height is 10% lower than your highest altitude.
To exemplify, if you went to an altitude of 10000 ft, the Descent phase will be activated once you descend below 8000 ft, and if you went to an altitude of 20000 ft, the phase is activated once you descend below 18000 ft.
The phase is activated as you descend below 3000 ft.
The phase is activated as soon as your wheels touch the ground (which seems like a reasonable criteria).
Taxi to Park
The phase is activated once your ground speed drops below 30 knots.
The phase is activated when the parking brake is set at your destination airport.