Metal fatigue suspected in Boeing engine failure

(NBC News) – Federal investigators looking into what caused the engine of a Boeing 777 to blow apart shortly after a United Airlines flight took off from Denver International Airport Saturday are have released their early findings.

“Regarding the fan blade that was fractured at the root a preliminary on-scene examine indicates damage consistent with metal fatigue,” National Transportation Safety Board Chairman Robert Sumwalt said Monday.

Investigators say it appears that a fan blade also damaged another fan blade.

“Basically it probably got hit as the other piece was separating,” Sumwalt said.

The United Airlines plane was flying from Denver to Honolulu Saturday when it suffered engine trouble shortly after takeoff. Pieces of the engine rained down on a Colorado neighborhood.

The pilot brought the plane back to Denver for an emergency landing. Passengers were not hurt but were shaken.

“It’s terrifying,” passenger Lindsay Loock said. “You hear those noises when you are on an airplane and go ‘Oh, that’s not normal at all!'”