General Electric has ordered inspections on all 120 GEnx engines operating on Boeing 747-8s and 787s to check for installation errors of a component now linked to an engine failure in China last month.
The service bulletin issued on 4 October calls for a one-time inspection of the first stage low-pressure turbine (LPT) nozzle, a non-rotating part that directs the air flow into the trailing LPT stages.
GE issued the bulletin four days after completing a tear-down inspection of a GEnx-2B turbofan that was damaged during a rejected take-off by an AirBridge Cargo 747-8 in Shanghai.
The National Transportation Safety Board and the US Federal Aviation Administration (FAA) initially linked the incident to two other LPT failures of GEnx engines in late July and early August caused by cracks on the forward end of the fan midshaft, which connects the LPT to the inlet fan.
But closer inspections of the AirBridge Cargo engine revealed that no cracks or fractures of the fan midshaft, which pointed to an installation problem within the LPT itself.
GE emphasises that the GEnx engine family has accumulated a reliable safety record despite the high-profile contained engine failures on the 747-8 and 787. The engine fleet has achieved a dispatch rating of 99.9% with 225,000 flight hours in less than two years of service.
The fan midshaft cracking and fracturing incidents were traced last month to a new, lead-free coating that allowed the component to corrode rapidly under certain conditions. GE switched to a leaded coating already used on the GE90 to correct the problem.
Source: Air Transport Intelligence news
