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.
A Boeing jet has scattered debris over a residential area near Denver after one of its engines failed on take-off.
The Boeing 777, with 231 passengers and 10 crew on board, was able to return safely and land at Denver airport. No injuries were reported.
Police in the town of Broomfield posted pictures of what appears to be the front of an engine casing in the front garden of a home.
Passengers on board described a "large explosion" shortly after take-off.
Flight 328, a United Airlines plane bound for Honolulu, suffered a failure in its right-hand engine, the Federal Aviation Administration (FAA) said.
One passenger who was on the flight told AP news agency that the pilot was giving an announcement when there was a loud explosion.
"The plane started shaking violently, and we lost altitude and we started going down," David Delucia said.
He added that he and his wife placed their wallets in their pockets so that "in case we did go down, we could be ID'd".
Images posted online showed smoke trailing from the engine. One video apparently shot from inside the plane shows an engine on fire and stripped of its casing.
The incident happened shortly after 13:00 local time (20:00 GMT) on Saturday.
Broomfield police urged residents not to touch or move the debris. The FAA and the National Transportation Safety Board will be carrying out an investigation.