Professor Amy Edmondson at Harward Business School explains in three steps how to learn from failures, how to build an environment where people are encouraged to speech, to point out what does not work as it should - even if it's about a "minor" thing.
She illustrates how lessons were learned at NASA, from the Columbia disaster on January 2003. Failures are part of our life this is why we have to be able to put in place processes and procedures that allow to actively learn from them.