General Electric is contacting operators of its CF6-80E1 engines in Asia to check for corrosion on the powerplant's high-pressure turbine blades, following three engine shutdown events on China Airlines Airbus A330-300s.
Hot corrosion caused the incidents, in December 2010 and January 2011, in which flights turned back. The blades involved were in the first-stage high-pressure turbine of certain high-cycle CF6-80E1 engines.
"Preliminary analysis strongly indicates the corrosion damage on the blade surface may have been caused by certain environmental conditions, such as air pollution and other contaminants. The damage on the blades was extensive and they could not be repaired," says GE Aviation.
GE is contacting other CF6-80E1 operators in the region to determine if their blades have similar corrosion damage.
Recoating or Replacement
"We are still early in this process and are not sure if the problem has affected operators to the same extent that China Airlines has experienced," says GE.
GE Aviation introduced a more robust blade in 2008, with a
resistant coating "that enhances blade life."
China Airlines' engines were delivered from 2004. GE introduced a more robust blade on the engine as standard in 2008, with a resistant coating "that enhances blade life," and issued a service bulletin to operators recommending inspection for corrosion during routine engine overhauls. Blades with minimal corrosion can be repaired with a coating.
"However if the corrosion is too much, the blade should be replaced with the new improved HPT blade," says GE.
GE is working with China Airlines to retrofit the new blades. While the airline says it needs to replace only the affected blades, it is replacing all engine blades on its 18 A330s as a precaution. Seventy percent of the work, covering 41 engines, is complete and all blades will be replaced by May.
Taiwan's China Airlines adds that GE investigated its maintenance procedures and found the carrier conformed with instructions, and the operating environment was "no different" from other carriers.