I operate under a philosophy that people are going to make mistakes. But when something does go wrong, make sure I'm the first one to know, because I can't help you fix it if I don't know about it. The whole organization is run that way. You have to give people a chance to own their areas, but you also have to agree that they're going to come and tell you as soon as something goes awry. I think that allows people to move up the learning curve faster. It's like watching your kids go out and swim. You're always within arm's length when they're swimming, so that you're there to grab them back.
This is similar to the thinking I wrote about in an article on The 99 Percent, "How to Bounce Back From a Big Mistake," especially point 2 - Tell Your Leader.