NTSB recommends frequent GE engine testing
Sept. 18, 2012, Washington, D.C. - The US National Transportation Safety Board (NTSB) has recommended the Federal Aviation Administration (FAA) carry out frequent inspections on General Electric aircraft engines, GEnx-1B and GEnx-2B following two safety incidents.
September 18, 2012 By aerospace-technology.com
GE manufactures the GEnx dual-rotor turbofan engine for the Boeing 787 and 747-8 aircraft.
NTSB has found that the engine fan shafts on the GEnx engines were vulnerable to cracking at the forward end of the shaft, where a retaining nut is installed.
A crack in that shaft caused the failure of an engine of a Boeing Co 787 Dreamliner jet being tested before delivery in Charleston, South Carolina in July.
Then on Tuesday, a 747-7 freighter using a similar model engine failed during attempting takeoff in Shanghai. However, the cause of that failure has not yet been determined.
"Because of the immediate threat of multiple engine failures on a single aircraft and the availability of an appropriate inspection procedure, there is an urgent need for the FAA to act immediately," NTSB said.
Despite wider checks of affected engines and coordination between the FAA, Boeing and GE to resolve safety issues, the NTSB stated that immediate action was necessary.
The decision was made because 36 engines currently pending inspections remain in service on 747-8 cargo freighters.
NTSB has expressed concerns about the potential for future incidents, as well as the possibility that multiple engines on the same aircraft could experience an FMS failure.
FAA said it completed tests on all affected passenger jets and would soon issue an emergency airworthiness directive and take appropriate action to deal with the safety issues.
GE said it had almost completed ultrasound inspections on the fan mid-shaft engine part of all but nine aircraft, and started using a coating and lubricant process used for the GE90 on the shaft to prevent cracking.