Originally Posted by
albatross
I assume that they returned the eng to normal power settings for landing.
Probably not. There are several situations where the preferred procedure with some engines (compressor stalls in a CF6, oil pressure in a J-52) is to reduce power to a stable level and leave it there. The probability of catastrophic failure is reduced if you don't try to change the thrust level.
About 10 years ago I had compressor stalls on a CF6 on a 747 Classic, about 2 hours into a Turkey - Hong Kong flight. Reducing N1 to about 80% worked for a couple hours, then reducing to idle worked for the rest of the flight. UNTIL the F/O who was flying decided he wanted to bring it up to approach thrust on final. Within 15 seconds or so the engine chugged again, and spewed a good portion of our turbine blades into Hong Kong Harbor. On landing roll it started overtemping even at idle, so we shut it down.