US air safety regulators are considering whether to require further inspections of certain Pratt & Whitney engines before one that powered a United Airlines Holdings Inc. flight crashed on Saturday over a city near Denver, the Federal Aviation Administration said.
The revelation came when US security investigators said they found evidence of “damage consistent with metal fatigue” on one of the engine fan blades that had been completely blown off. That loose blade apparently cut off part of a second blade that was also fractured, Robert Sumwalt, president of the National Transportation Safety Board, told a news conference on Monday night.
Sumwalt said investigators are investigating why an external cover known as the bonnet came off, as well as why the damaged engine remained on fire even after the fuel was turned off by the flight crew.
Last weekend’s incident was the third in a series of failures involving the same engine and aircraft types in recent years. American regulators had previously ordered intensified fan blade inspections after a previous engine failure on another United flight on a Boeing 777 in 2018. Then, in December, an engine failed during a Japan Airlines Co. flight to Tokyo, taking to a new FAA review.
There were similarities between the incident in Japan and that in Colorado. The Japan Transport Safety Council said a fan blade that broke off that engine showed signs of metal fatigue. Another blade was broken almost in half.