Australia's ATSB is cautioning CFM56-7 and -5 operators to potential engine failures due to "premature wear" of compressor stator vane bushings. The recommendation
, made Tuesday, comes on the heels of a probe into an August 20, 2009 incident
in which a Virgin Blue Boeing 737's No. 1 engine experienced a compressor surge, which threw parts into the gas path, causing significant downstream damage. The incident occurred while the plane was climbing out of Launcheston en route to Sydney. The crew brought the plane back safely to Launcheston.
ATSB's report on the incident (.PDF)
found that CFM was aware of the inner bushing wear problem and issued several service bulletins to address it. However, the incident happened before the engine reached the earliest inspection threshold, which is 24,000 hours.
ATSB and CFM identified 34 similar "occurrences" in the CFM56 fleet, including 16 compressor surges, eight in-flight shutdowns, and 10 incidents discovered only post-flight, during routine inspections. CFM noted that of the eight in-flight shutdowns, only one occurred before the 24,000-hour threshold, and the inspection thresholds are set to limit the likelihood of a dual-engine event, ATSB said in its report.