A Virgin Atlantic jet bound for Las Vegas is making an emergency landing at Gatwick Airport after developing a problem with its landing gear.

The airline says the Boeing 747 "is preparing to implement a non-standard landing procedure" because of "a technical issue with one of the landing gears."

The airport said the flight, VS43, took off at about 11:45 a.m. Monday. Flight-tracking websites show it circled off the coast of southwest England before turning back to Gatwick, south of London. It was circling near the airport and had yet to land three and a half hours after takeoff.

Emergency services were on standby for the landing — standard procedure when a plane has to land with a technical problem.