But the terrified passengers then cheered and applauded the hero pilot after he landed the jumbo jet safely.
Terrified passengers who had endured a nerve-racking few hours circling above the south coast after the problem was identified spoke of their relief as the pilot of Flight VS43 managed a "textbook" landing despite one of the plane's five sets of landing gear not deploying.
Passengers, many heading for a New Year break in Las Vegas, adopted the brace position and emergency services were on standby as the giant aircraft, packed with 447 passengers and 15 crew, came into land.
And there was spontaneous applause as the pilot pulled off the delicate landing without a hitch and the jet rolled safely to a stop.
Describing the mood on the plane, Dan Crane, 24, from Bromsgrove, Worcestershire, said it was "anxious, a lot were worried, some crying. The mood was quiet and (we were) just waiting for the captain's next announcement."
Mr Crane, who was with family and friends, said the crew kept everyone informed, adding: "They said it was an emergency landing and we had to brace on impact."
The jet appeared to be flying with only three quarters of its landing gear down after a set of wheels on the starboard wing refused to drop, but the pilot still managed to land it safely.
It had to turn back towards London over the Devon coast less than 30 minutes after taking off for America.
Passengers on board were asked to adopt the brace position as the plane came in to land.
"When we landed you can imagine the relief. We were told the plane had a hydraulic problem but were not told that it was the wheels," said passenger Mike Kaufman.
"We were told about the brace position around two hours before we landed and ran through it several times before we landed. The crew were calm and that made us calm.
"The landing was smoother than others I've had. It was probably less dramatic on board than it was watching it on TV. It is going to go down as one of the greatest emergency landings in history."
Other passengers took to Twitter after touching down to thank the flight crew.
Kelly Coates tweeted: "#VS43 currently on board the Virgin Atlantic Flight VS43. Massive thank you to all of the crew for keeping everyone calm and safe ??"
Fate Swan wrote: "@virginatlantic the cabin crew and the pilot have been absolutely amazing and have been keeping us all calm and informed #VS43."
Another posted: "Top marks to Dave the pilot and all the excellent Virgin cabin crew for bringing us back to Earth safe and sound. #vs43."
A Gatwick Airport spokesman said: "Virgin Atlantic flight VS043 has landed safely after returning to Gatwick due to a technical fault. Following the emergency landing, passengers have disembarked the aircraft via stairs. At this time, only minor injuries have been reported."
A Virgin Atlantic spokesman said: "We can confirm that flight VS43 has landed safely back at Gatwick. Our priority now is to look after our passengers and crew."
Before it landed the plane made at least one low-level pass over the London Gatwick so engineers could observe the problem.
Others who saw the jet circling around the airport said the pilot was "tipping the wings" to try to use gravity to drop down the final part of the landing gear.
