Debris from an airplane fell onto suburbia on Saturday (local time) during an emergency landing after one of its engines exploded midair.
Engine casing from the United Airlines flight rained on a Denver suburb following the failure, narrowly missing a home.
The plane landed safely, and nobody aboard or on the ground was reported hurt, authorities said. The National Transportation Safety Board said it had opened an investigation into the incident.
The Federal Aviation Administration said in a statement that the Boeing 777-200 returned to the Denver International Airport after experiencing a right-engine failure shortly after takeoff.
Flight 328 was flying from Denver to Honolulu when the incident occurred, the agency said.
United said in a separate statement that there were 231 passengers and 10 crew on board. All passengers were to be rebooked on a new flight to Hawaii, the airline said.
The Broomfield Police Department posted photos on Twitter showing large, circular pieces of debris leaning against a house in the suburb about 40 kilometres north of Denver. Police are asking that anyone injured come forward.
Passengers recall the airplane's 'violent shaking'
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,” David Delucia, who was sitting directly across the aisle from the side with the failed engine, said.
“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 licenses and put them in their pockets so that “in case we did go down, we could be ID’d,” Delucia, who was still shaken up as he waited to board another flight for Honolulu, said.
Explosions heard on the ground
On the ground, witnesses also heard the explosion and were scared for those on board.
Tyler Thal, who lives in the area, said 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.”
Thal was relieved to learn no one was injured or killed from what he saw.
Video posted on Twitter showed the engine fully engulfed in flames as the plane flew through the air.
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 hurtle 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 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.
“And if anyone had been in the truck, they would have been dead.”
Experts warn "cracks" in aviation safety need to be addressed
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 armoured casing around the engine that is designed to contain the damage, John Cox, an aviation safety expert, said.
“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.
Pilots practice 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
Former National Transportation Safety Board 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 criticised the FAA over the past decade as “drifting toward letting the manufacturers provide the aviation oversight that the public was paying for.”
That goes especially for Boeing, he said.
Despite the scary appearance of a flaming engine, most such incidents don’t result in loss of life, Cox said.
The last fatality on a U.S. airline flight involved such an engine failure on a Southwest Airlines flight from New York to Dallas in April 2018.
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