A United Airlines plane has rained debris on Denver suburbs, narrowly missing a home, after it suffered a catastrophic engine failure shortly after take-off on Saturday. The Boeing 777-200 returned to the airport safely for an emergency landing, with no reports of anyone hurt.
United said in a statement there were no reported injuries on Flight 328 from Denver International Airport to Honolulu, which had 231 passengers and 10 crew on board.
Police in Broomfield, Colorado posted photos of pieces of debris from the plane near houses and other buildings but there were no immediate reports of any injuries on the ground.
Passengers recounted a terrifying ordeal that began to unfold shortly after the plane full of vacationers took off.
The aircraft was almost at cruising altitude and the captain was giving an announcement over the intercom when a large explosion rocked the cabin, accompanied by a bright flash.
“The plane started shaking violently, and we lost altitude and we started going down,” said David Delucia, who was sitting directly across the aisle from the side with the failed engine. “When it initially happened, I thought we were done. I thought we were going down.”
Delucia and his wife took their wallets containing their driver’s licences and put them in their pockets so that “in case we did go down, we could be ID’d,” said Delucia, who was still shaken up as he waited to board another flight for Honolulu.
The FAA said it and the National Transportation Safety Board (NTSB) would investigate.
Images posted by police appeared to show large pieces of debris including an engine casing from the plane scattered outside a home and on a turf field. A video on social media showed a cloud of black smoke being left by a plane.
“Something blew up,” a man could be heard saying.
In an audio recording, a United pilot could be heard making a mayday call to air traffic control.
“Mayday, aircraft just experienced engine failure, need to turn immediately,” the pilot said, according to audio from the monitoring website liveatc.net that was reviewed by Reuters.
Denver resident 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.
He estimated the circular engine cowling at 15 feet (4.5 meters) in diameter. Fine pieces of the fibreglass 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.
“If it had been 10 feet different, it would have landed right on top of the house,” he said in a phone interview with the AP. “And if anyone had been in the truck, they would have been dead.”
Broomfield police appealed for people not to move any debris they might find. “The NTSB wants all debris to remain in place for investigation,” the department said on Twitter.
Broomfield is a suburb about 25 miles north of Denver. Tyler Thal, who lives in the area, told the Associated Press he was out for a walk with his family when he noticed a large commercial plane flying unusually low and took his phone out 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,” he said in a phone interview.
“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. The plane just kind of continued on and we didn’t see it after that.”
Thal was relieved to learn later that the plane had made a safe landing.
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 discs inside the engine suffer some sort of failure and breach the armored casing around the engine that is designed to contain the damage, said John Cox, an aviation safety expert and retired airline pilot who runs an aviation safety consulting firm called Safety Operating Systems.
“That unbalanced disk has a lot of force in it, and it’s spinning at several thousand rotations per minute … and when you have that much centrifugal force, it has to go somewhere,” he said in a phone interview.
Pilots practise how to deal with such an event frequently and would have immediately shut off anything flammable in the engine, including fuel and hydraulic fluid, using a single switch, Cox said.
Boeing said its technical advisers would assist the NTSB with its investigation, while United pledged to “work with federal agencies investigating this incident”.
Former NTSB Chairman Jim Hall called the incident another example of “cracks in our culture in aviation safety (that) need to be addressed”.
Hall, who was on the board from 1994 to 2001, has criticized the FAA over the past decade.
The last fatality on a US airline flight involved such an engine failure on a Southwest Airlines flight from New York to Dallas in April 2018.
A passenger was killed when the engine disintegrated more than 30,000 feet above Pennsylvania and debris struck the plane, breaking the window next to her seat. She was forced halfway out the window before other passengers pulled her back inside.
In that case, the breakdown was blamed on a broken fan blade in an engine of the Boeing 737.