David Delucia was settling back into his airplane seat and starting to relax on his way to a long-awaited vacation when a huge explosion and flash of light interrupted an in-flight announcement and put him in survival mode.

The Boeing 777-200, headed from Denver to Honolulu on Saturday with 231 passengers and 10 crew aboard, suffered a catastrophic failure in its right engine and flames erupted under the wing as the plane began to lose altitude.

As Delucia and his wife prepared for the worst, people in this Denver suburb reacted in horror as huge pieces of the engine casing and chunks of fiberglass rained down on a sports fields and on streets and lawns, just missing one home and crushing a truck. The explosion, visible from the ground, left a trail of black smoke in the sky, and tiny pieces of insulation filled the air like ash.

The plane landed safely at Denver International Airport, and no one on board or on the ground was hurt, authorities said. But both those in the air and on the ground were deeply shaken.

“When it initially happened, I thought we were done. I thought we were going down,” said Delucia, who stuffed his wallet in his pocket so he could be easily identified if the plane did go down. “The pilot did an amazing job. It was pretty unnerving.”

A video posted on Twitter showed the engine fully engulfed in flames as the plane flew through the air. Freeze frames from different video taken by a passenger sitting slightly in front of the engine and posted on Twitter appeared to show a broken fan blade in the engine.

Authorities have not released any details about what may have caused the failure.

The Broomfield Police Department posted photos on Twitter showing large, circular pieces of debris that appeared to be the engine cowling leaning against a house.

Tyler Thal, who lives in the area, told The Associated Press that he was out for a walk with his family when he noticed a large commercial plane flying unusually low and took out his phone to film it.

“While I was looking at it, I saw an explosion and then the cloud of smoke and some debris falling from it. It was just like a speck in the sky, and as I'm watching that, I'm telling my family what I just saw and then we heard the explosion,” he said in a phone interview. “The plane just kind of continued on, and we didn't see it after that.”

Kirby Klements was inside with his wife when they heard a huge booming sound, he said. A few seconds later, the couple saw a massive piece of debris fly past their window and into the bed of Klements' truck, crushing the cab and pushing the vehicle into the dirt.

Fine pieces of the fiberglass insulation used in the airplane engine fell from the sky “like ash” for about 10 minutes, he said, and several large chunks of insulation landed in his backyard.

Based on initial photos and videos posted by passengers, aviation safety experts said the plane appeared to have suffered an uncontained and catastrophic engine failure.

Such an event is extremely rare and happens when huge spinning pieces inside the engine suffer some sort of failure and breach an armoured casing around the engine that is designed to contain the damage.