The most critical resource for ensuring you have the fastest possible repair of critical equipment is your team of repair techs. When one tech does a repair, does only that tech gain knowledge of that repair? There's a reason why football coaches review video footage of games with the entire team — it dramatically helps them to improve their game. You should do the same thing.
Any time critical equipment is down, you should not only send in your A-team (or the closest approximation), but also a tech equipped with a video camera (these are inexpensive today) to record what's happening. While you probably can't sit down with the whole maintenance department to review this, you can review with a few people at a time. Look for and discuss what went right and what could have been done better (use the pause button as needed). Update the procedures with what you learn. Techs that go through this will gain repair knowledge on that equipment and are likely to gain knowledge they can use elsewhere.
Find links to Parts 1 through 5 of this series below.