Posted on September 14, 2012 at 9:34 PM
Friday, Sep 14 at 10:31 PM
SEATTLE -- The National Transportation Safety Board issued two urgent recommendations affecting Boeing's newest airplanes Friday.
This comes after inspectors discovered cracks in engines mounted on two 787 Dreamliners and a 747-8 cargo jet.
The engines are built by General Electric as part of their new fuel efficient GEnx line.
Inspectors found cracks in what's called the fan mid-shaft. That's the area where two sections of the shaft are joined by a torque nut.
NTSB officials say the discoveries have led them to fear multiple engines on the same plane could fail. The results could be catastrophic.
The first sign of trouble came earlier this summer during a taxi test of a 787 at the Boeing plant in Charleston, S.C.
As the pilots rolled down the runway, one the engines began to idle down.
An inspection revealed a fracture in the fan-midshaft.
The fan blades shifted and the engine started to tear itself apart.
When GE began inspecting other GEnx engines for cracks they found one on another 787, that hadn't yet flown.
Then, just this week, a Boeing 747-8 lost an engine during takeoff roll in China. The pilots aborted before getting airborne
So Friday, the NTSB issued two urgent recommendations calling on the FAA to require ultrasonic inspection of all GEnx-1B and 2B engines. They also recommended inspections to be ongoing and frequent so that they can detect small cracks before they become big ones.
GE believes the cracks are related to corrosion caused by a new coating on the fan-midshafts that didn't keep out moisture.
There were significant delays in the 787 program. And so GE is looking into whether that corrosion happened in the time between the manufacturing of parts and installation on the aircraft.