This problem brings back a few memories of long days on the old A model.
We encountered this problem when we went to the enhanced -C30s, it happened during the DCA check mostly, but sometimes on a normal accceleration at start up, one engine would start popping.
Sometimes an FCU change would cure it, other times we would change both the FCU and the Gov, on one occasion the #2 was popping, as we had used up our spares, we swapped the FCU and Gov between 1 and 2, it cured # 2 and # 1 was okay.
We never really got an answer from Allison why this was happening, what we put it down was that on the contract we had at the time the C30 had to be high spec , to get the high spec, the O/H shop were working to very close tolerances plus the fact that the compressor was running a bit faster, the fuel scheduling was very critical.
Although we were able to cure it most of the time, on some occasions if it was doing it during the DCA check, we had to live with it if it wasn't too violent.
What are the specs on your engines?
Good Luck.
Tynecastle.
Last edited by Tynecastle; 25th Oct 2004 at 13:07.