My college roommate was a pilot, and his explanation was that on occasion some devices can cause static or interference on the pilot's headsets. Since communica

My college roommate was a pilot, and his explanation was that on occasion some devices can cause static or interference on the pilot's headsets. Since communication with the tower is critical during takeoff & landing, the policy of power-off is in effect. I guess it's not as critical during taxi, since that is allowed.