(CNN) -- Just two months after an engine cracked and failed during test aboard a Boeing 787, federal plane inspectors have found a second engine problem on a different Dreamliner, the National Transportation Safety Board announced.
The NTSB identified the problem as a cracked fan midshaft on a Dreamliner General Electric GEnx-1B turbofan engine, the group said in a written statement posted on its website Thursday. The 787 had not yet flown when investigators identified the engine problem, investigators said.
Inspectors uncovered the cracked second engine during an inspection of all in-service engines of that type, the NTSB said. The statement included no further details of the discovery. The NTSB, which investigates all U.S. civil aviation accidents, said its investigation of the engine troubles is continuing.
GEnx engines are manufactured at a General Electric facility in Cincinnati.
The first Dreamliner engine problem occurred on July 28 during a taxi test at Charleston International Airport in South Carolina.
No passengers were on board, and no injuries were reported, although burning debris from the failure did cause a small brush fire near the tarmac.
In a third related development, a similar General Electric engine on a different kind of aircraft -- a GEnx-2B on a Boeing 747 -- lost power during takeoff last September 11 at Shanghai Pudong International Airport. That incident is under investigation by the Civil Aviation Administration of China, the NTSB said.
Preliminary findings showed that the failed engine's fan midshaft on the 747 was "intact and showed no indications of cracking," the NTSB said.
The Federal Aviation Administration, General Electric and Boeing are involved in the Chinese investigation.
Boeing rolled out the 787 Dreamliner last year, three years late and billions of dollars over budget. United Airlines is scheduled to begin flying the first U.S. domestic routes for the aircraft in November.
Fanfare has been loud surrounding the technologically advanced Dreamliner. Among other touted features, it's the first commercial airliner made mostly of light-weight carbon composites, requiring less fuel than conventional airliners.