A-320 engine roll-back!

[Ignition Override]

I sat next to an A-320 Captain tonight in an airport. He told me that today, in the middle of the Gulf of Mexico, his left engine suddenly rolled back to idle during cruise flight. He quickly decided to descend to a lower altitude and there were no messages on the ECAM. The engine came back very soon to normal cruise power. It was not clear to me if there were any other surges before it came back. One of our Union Council Safety Reps was next to him as he entered his interesting safety report.

He said that many of the passengers could clearly hear the engine drop to idle power. They were in clear air at the time.
This might be interesting (and awkward?) for the FADEC community.

What about on the A-330 engine? Does it have the same exact FADEC software, whether certified for ETOPS or not?

[Carnage Matey!]

This seems to happen rather a lot on the A320, it's the FADECs way of protecting the engine from surges and won't necessarily trigger an ECAM warning if the engine is windmilling fast enough. Do you know if it was a CFM or and IAE engine?

[moleslayer]

Operations Engineering Bulletin No. 164/1A refers to this occurence reported recently (Sept '04)

Transient speed target drop, in cruise, after a F-Plan modification.

After performing a DIR TO, the managed speed target drops below the current airspeed, and the autothrust commands idle to follow the speed target change.

There follow's a lengthy explanation, which those of you in posession of FCOM vol3 may like to read.

Moley.