It’s never a good sign when your pilot tells you to “pray.”

But that’s exactly what happened — twice — on a scary Air Asia X flight from Australia to Malaysia as the plane shook like a “washing machine” for two hours, according to passengers.

Air Asia Pilots Asks Passengers to ‘Pray’ During Wild Flight1:47

“The rattling started straight away,” Damien Stevens, who was on his way from Perth to Kuala Lumpur with a friend, told NBC News. “It was like being in a washing machine or on a compressor. The crew were really good, although the pilot asked us to pray twice and said he was scared too.”

Stevens said the Sunday morning flight out of Perth began to shake rapidly after they heard a “huge bang” about 75 minutes into the flight, which should have taken the Airbus 330 about six hours.

The exact cause of the incident remains unclear. Stevens said the airline was very forthcoming with information, though he said they told him the trouble stemmed from one of the engines and that the pilot had 44 years of experience.

“I’m not 100 percent sure,” he said, noting that he could not see the engine and could not definitively confirm. “It was the left engine, engine one. We flew back on one engine. It was either jammed, frozen, the engine belt broke — apparently a blade broke off.”