Interstingly RR requires operators of the Trent 700 powered A330 operators to do a periodic packs-on take-off to encourage surge. This is due to a HPC wear issue that can be brought on during a packs on take-off.
So if the operator has an engine go bang during this periodic take-off, they can then apply to AIB to fly-on for about 10 flights with packs-off take-offs before engine replacement.
Brgd's
