A passenger has told of her terror when a plane descended about 30,000 feet when it was forced to turn back to Darwin an hour into a Qantas flight to Brisbane, NT News reports.

Angie Smart, of Stuart Park, said the first indication the flight was in trouble was when the cabin became "uncomfortably hot".

"We heard the co-pilot announce the plane was returning back to Darwin and the seatbelt sign came on," she said. "Then suddenly we felt the harsh turbulence and the pilot announcing again that we had just dropped from 40,000 feet to 10,000 feet.

"I looked out the window and could clearly see the ground. I was thinking; Oh my God, are we going to crash?"


Smart said her panic was exacerbated when she heard a boy in front of her ask whether the Boeing 737-80 with 172 passengers on-board was going to crash.

"The cabin was so hot, they made a good decision to turn the plane back to Darwin."

After the flight turned back last Friday, a Qantas spokesman said a fault developed about an hour into the flight and the captain made the decision to return to Darwin.

St John ambulances were called to Darwin Airport as a precaution.

Smart said she decided not to take another flight but was given a full refund.

"I had been made redundant a few weeks ago and the trip was to get away and see some friends," she said.

"But after that I just decided it would be better to stay in Darwin." Vince Ashe, another passenger on board the flight previously told the Nt News they were notified by the captain that one of the airconditioners wasn't working and the other was struggling.

"Due to not being able to fix the aircon we had to return and they had dropped to a safer level because, at the height we were flying at, we were going to lose oxygen, so we dropped from 40,000ft to 10,000ft," he said.