<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by Can I help you:
Departure time is when the chocks are removed and the aircraft pushes back.
Arrival time is when the aircraft comes to a complete stop and the chocks are in place.
Chocks are the rubber/wood blocks placed behind the wheels to stop the aircraft from rolling back. </font>
I believe that chock's are removed when the jet-bridge comes off and not necessarily when the a/c pushes back.