Compressor Stall Problem Reported With A320 Engines
The National Transportation Safety Board's ongoing
investigation into last week's downing of US Airways Flight 1549
has centered on the aircraft's two CFM International turbofans,
which appear to have been knocked out simultaneously after an
encounter with a large flock of birds. The NTSB is exploring all
possible causes for the engines to lose power, however... and that
investigation has revealed some interesting tangents.
As ANN reported Tuesday, passengers who flew
on the same plane on January 13 -- two days before Flight 1549
ditched in New York's Hudson River -- reported a loud bang and
temporary loss of power in the plane's number two (right) on their
flight, which was attributed to a compressor stall. The NTSB has
since confirmed those reports.
Now, Newsday reports that two weeks before that incident, the
FAA issued an airworthiness directive on CFM56-5B engines... the
same type that were on N106US, the A320 that ditched in the Hudson.
That AD was related to, you guessed it, compressor stall incidents;
specifically, the AD calls for more stringent inspections of
engines which exceed upper operating temperature ranges when the
throttles are rolled back from takeoff power.
Earlier this month -- before Flight 1549 -- General Electric
spokesman Rick Kennedy told The Business Courier of Cincinnati
there had been 10 reported cases of compressor stalls on A320
family aircraft since April 2008, each lasting "a second or two."
In one of those cases, both engines on an Air France A320 suffered
apparent compressor stalls shortly after takeoff.
CFM is a joint venture of GE Aviation and French consortium
At this time, these revelations appear to have little to do with
what felled Flight 1549 on January 15. Both pilots onboard the
airliner say they saw a large flock of birds immediately before the
engines flamed out, and were unable to maneuver to avoid it.
Neither have reported any prior engine anomalies.
That seems to follow with early results of the NTSB's
investigation. "We have not found any indications of anomalies or
malfunctions with the aircraft from the time it left the gate in
LaGuardia... to the point at which the pilots reported a bird
strike and a loss of engine power," said Board spokesman Peter
Knudson on Tuesday.
Furthermore, analysis of the aircraft's right engine has
revealed broken turbine vanes, consistent with impact with foreign
matter... like with one or more large birds. Crews are still
working to recover the plane's left engine from the floor of the
Newsday adds that salvage crews were seen Tuesday circling
several areas of the A320's nose section with greasepens,
"apparently to indicate possible bird strikes."