That US National Transportation Safety Board has recommended inspections of all new Boeing 787 and 747-8 General Electric GEnx engines after a trio of recent incidents blamed on cracks in the engine’s turbine midshaft.
“We are issuing this recommendation today because of the potential for multiple engine failures on a single aircraft and the urgent need for the FAA to act immediately,” NTSB Chairman Deborah Hersman said, adding that the FAA, GE and Boeing had already taken important steps in addressing the problem.
The first incident came in July when a 787 GEnx-1B engine failed during ground tests in South Carolina, expelling metal debris and starting a small grass fire. In late August, an inspection of a GEnx-1B on a separate 787 that had yet to fly turned up a crack in the fan midshaft.
Then last week, a Boeing 747-8F aborted takeoff from Shanghai after losing power in one of its four GEnx-2B engines, which are closely related to the 787 engines. Again, initial inspections indicated damage to the engine’s turbine section.
In response, GE has developed an ultrasonic method that can be used to inspect the engines without removing them from the aircraft, the NTSB said. All GEnx-1Bs used on 787s have already been inspected, as have all GEnx-2Bs used on passenger versions of the 747-8. Inspections of 747-8Fs are ongoing and expected to be completed this week.
The NTSB said such inspections should be repeated at regular intervals in order to catch any cracks before they grow to a point where they could cause engine failure.
GE believes it has determined the cause of the cracks and has changed the way the shafts are coated during production, the NTSB said.
Boeing has continued to deliver 787s equipped with GE engines since the July incident, including an aircraft handed over to Air India early this month. Boeing said the aircraft’s engines had been thoroughly inspected and cleared prior to delivery.
The GEnx engines are one of two options for the 787, which can also be fitted with Rolls-Royce Trent 1000s. The Rolls-Royce engines have had problems of their own, with 787 launch customer All Nippon Airways earlier this year forced to ground its fleet of the aircraft due to engine gearbox corrosion. The gearboxes were replaced without incident.
The 747-8 exclusively uses the GE engines.