A fire alarm caused a brief evacuation of the TRACON tower at Sky Harbor International Airport Sunday afternoon.
TRACON, which stands for Terminal Radar Approach Control, is a three-story building at the base of the air traffic control tower.
Ian Gregor, spokesman for the Federal Aviation Administration, said the tower was evacuated when the alarm sounded, but no fire was present.
Per contingency plans, Albuquerque took over monitoring Phoenix airspace, Gregor said.
Officials implemented a ground stop at 2:39 p.m. for all flights departing for Phoenix from airports within an hour's flying time. That hold was lifted at 3:15 p.m. and normal operations resumed.
Gregor said there were a handful of airborne holding delays, none of which lasted longer than 20 minutes.
