US accident investigators have cited metal fatigue as a possible contributing factor in the recent engine failure incident involving a United Airlines Boeing 777 aircraft.
The passenger jet made an emergency landing in Denver, Colorado, on Saturday after its right engine blew apart, and engine parts fell into a residential area.
The National Transportation Safety Board is looking into the cause of the incident.
The aircraft suffered engine problems just after taking off from Denver airport. Preliminary findings show two fan blades were fractured and the remainder of the blades exhibited damage.
An NTSB senior official said on Monday it is possible that damage to one of those fan blades was caused due to metal fatigue.
The NTSB also released images of the Boeing jet with the damaged engine.
They show one of the engine's fan blades has completely gone, and part of another blade is also missing. They also show the fuselage is partially damaged.
NTSB investigators are looking into the engine and examining parts they have recovered. They are also analyzing photos and videos taken by passengers to identify the cause of the accident.