Investigators with the National Transportation Safety Board are closer to discovering what caused a Boeing 787 Dreamliner engine to fail on July 28.
The NTSB sent an investigator to Charleston after an engine failed on a Dreamliner during a pre-delivery taxi test. A team was also sent to a GE facility in Cincinnati, OH to inspect a GEnx engine.
"The NTSB has determined that a fan mid-shaft on the failed GEnx engine fractured at the forward end of the shaft, rear of the threads where the retaining nut is installed," states a release from the NTSB.
Officials say the fan shaft connects the fan and booster in the front of the engine to the low pressure turbine in the back.
According to the release, there is still more work to be done.
"The fan mid-shaft is undergoing several detailed examinations including dimensional and metallurgical inspections."
The NTSB says investigators have also begun reviewing the engine manufacturing and assembly records.
Officials with the NTSB, FAA, Boeing and GE Aviation are working together to examine the newly designed GEnx aircraft engine that failed.
The investigation is ongoing.