General Electric has decided that more inspections of its GEnx jet engines are in order after investigators determined that a Boeing 747 engine failure in Shanghai last month was different than the engine failure during a Boeing 787 pre-flight test at Charleston International Airport in July.
The engine manufacturer will “within the next couple of days” issue a service bulletin calling for inspections of the low-pressure turbine section of “certain GEnx engines in service,” GE spokesman Rick Kennedy said Tuesday.
Kennedy could not say if this week’s service bulletin, first reported by The Wall Street Journal, would apply to the same GEnx engines that are already subject to a Federal Aviation Administration airworthiness directive from last month.
That FAA order required all in-service GEnx engines to be checked every 90 days for driveshaft cracks, the problem in the engine that failed July 28 in North Charleston and in another engine on another pre-delivery 787 in Washington state.
A spokesman for the National Transportation Safety Board, which has been investigating the issues, declined to comment on the prospect of a new GE service bulletin. The FAA did not return a message Tuesday afternoon.
Hans Weber, a jet engine expert in California, said the acknowledgement that there is more than one issue with the GEnx is cause for continued concern.
“Generally the more different problems you have with anything,” Weber said, “the more doubtful people become about the reliability of the product.”
A preliminary inspection of the GEnx-2B engine that failed in Shanghai showed similar damage to the low-pressure turbine that was found in the GEnx-1B engine after the North Charleston incident. But further investigation showed the 747 engine’s fan midshaft did not crack like the 787 engine’s shaft did.
Weber, president of TECOP International Inc., found the damage to that particular section of the engine puzzling.
“I’m just one of many people who are scratching their heads, especially since the low-pressure turbine is actually operating in a friendly environment,” he said. “The hottest and highest stress environment is experienced by the high-pressure turbine.”
Officials from Boeing, all of whose South Carolina-built 787s to date are powered by GEnx engines, have projected calm as the investigations continue and GE figures out fixes.
Operating under the understanding that corrosion is to blame for the cracks, GE is applying a coating to new fan midshafts to solve that problem.
In Charleston on Monday, Boeing CEO Jim McNerney called the issues “growing pains in a new engine” that would not slow down the 787 program.
But as McNerney spoke, the chief executive of Qatar Airways, Akbar Al Baker, declared that he would not take delivery of any of the 30 Dreamliners his airline has on order until the GEnx engine issues are resolved.
Weber said that could affact “Boeing’s short-term cash flow if they can’t make deliveries.”
Still, Weber maintained that the engine problems are “relatively quickly fixable,” and predicted that investigators would determine the cause of the China incident by the end of the week.