United Airlines engine explosion over Denver prompts company to ground Boeing 777s - CBS News

Federal aviation regulators are ordering United Airlines to step up inspections of all Boeing 777s equipped with the type of engine that suffered a catastrophic failure over Denver on Saturday.

Pieces of the casing of the engine, a Pratt & Whitney PW4000, rained down on suburban neighborhoods.

The National Transportation Safety Board said in a separate statement that two of the engine's fan blades were fractured and the remainder of the fan blades "exhibited damage." The NTSB did caution that it was too early to draw conclusions about how the incident happened.

Video posted on Twitter showed the engine fully engulfed in flames as the plane flew through the air.

airline with the Pratt & Whitney PW4000 in its fleet, the FAA said.

Airlines in Japan and South Korea also operate planes with the Pratt & Whitney engine

Nikkei reported that Japan's Ministry of Land, Infrastructure, Transport and Tourism also ordered the planes out of service, and the ministry said an engine in the same PW4000 family suffered unspecified trouble on a JAL 777 flying to Haneda from Naha on December 4