Originally Posted by
leongood
I said fire because there were flames coming out of the back of the engine. Could have been a compressor stall though. There was repeated loud banging - I thought it was a part rattling around the inside of the engine cowling.
That is a compressor stall--actually, a series of compressor stalls. During the stall the fuel doesn't burn so the fuel/air mixture moves out of the burner section into the turbine section and tailpipe. When they ignite you get the pulsing flame in the tailpipe.