(Reuters) - The National Transportation Safety Board said on Wednesday that the failure of a General Electric Co jet engine on a Boeing Co 787 Dreamliner last month was a contained incident of the sort that does not normally pose an immediate safety risk.
The NTSB said that a shaft in the GEnx engine fractured, leading to the incident in Charleston, South Carolina, in which debris fell from the engine and sparked a grass fire near the runway. The jet in question was being tested before Boeing shipped it to a customer.
"A contained engine failure is a specific engine design feature in which components might separate inside the engine but either remain within the engine's cases or exit the engine through the tail pipe," the NTSB said in a statement. "This design feature generally does not pose immediate safety risks."
The agency said it will continue to investigate the engine failure, including a metallurgical analysis of the properties of the shaft that failed.
GE spokesman Rick Kennedy said the roughly 80 GEnx engines installed on aircraft around the world remain in use.
"We're not aware of any issue that would hazard the safe flight of aircraft powered by these engines," Kennedy said. "We're continuing to ship engines to Boeing."
He noted that of 25,000 engines wholly or partly made by GE that are in use, there have been six failures of shafts over the past decade.
Boeing spokesman Doug Alder said the company was "working very closely with investigators and GE," but declined further comment.
GE's jet engine business competes with United Technologies Corp and Rolls-Royce Holdings PLC
(Reporting by Scott Malone in Boston and Bill Rigby in Seattle; Editing by Gerald E. McCormick and Leslie Adler)