They were less than an hour from their idyllic vacation when suddenly they wondered whether they would survive.

“We heard a tremendous bang, and then there was a sudden vibration — a shaking because the engine mount was shaking,” Canadian tourist Wayne Smellie told CNN affiliate KITV.

United Airlines Flight 1175, from San Francisco to Honolulu, had just lost the cover off its right engine. It was carrying 373 people, including many foreign vacationers.

“There was this mighty noise, and you knew something was wrong,” UK tourist Alison Grennan told KITV. “There was instant shock and panic.”

As pieces of metal rattled loudly, passenger Erik Haddad recorded video of the plane over the Pacific.

“That looks bad, plane and simple,” he tweeted.

Kathleen Clifford told CNN affiliate KHON she picked up her phone and contacted her family.

“At the end, I told my family I love them,” she said.

Jeff Carter posted on Instagram that he was calmly bracing for possible death.

“I figured the vibration would destroy the airframe,” Carter told CNN.

The Boeing 777 is powered by Pratt & Whitney’s PW4000 112-inch engines, the engine’s manufacturer said. It’s not clear why the malfunction happened.

“Pratt & Whitney is supporting the authorities in their investigation,” the company said in a statement.

The plane safely landed Tuesday at Honolulu’s Daniel K. Inouye International Airport. But the incident left many passengers traumatized.

“Scariest flight of my life,” Maria Falaschi‏ tweeted after she landed.

Others, such as Cheryle Tillman of California, told KITV they won’t be flying again anytime soon.

“I’m going to take a cruise home, because the flight was just horrible,” she said.

Grennan said the experience was so bad, she’s deferring a trip to Fiji.

“We are flying to Fiji in a couple of nights,” she said, “and I’m thinking Hawaii would be a nice place to live for a while.”