'We' use the big Antanovs on a regular basis, and this is a standard requirement for them. I believe their slow spool up time is a byproduct of their design timing - they were some of the Russians first 'big' jets which suffered from compressor airflow problems during acceleration (I think). Certainly I've seen/heard one 'pop' an engine whilst lined up and subsequently start its run up time all over again (no, they didn't taxi back....). Have also heard that they talked of fitting RB211s to later models, and a quick 'Google' confirmed that, but no idea if they ever did. We've also used the An 225, now that was impressive!