It takes a great deal of work to plan and execute an airport emergency exercise. They require hundreds of people-hours to organise with meetings, discussions, working groups, control plans and reviews. Approvals go up and down multiple reporting lines and resources (people, equipment and money) are committed.
And yet, I think the hardest part of this process, it that it all leads to everyone, and especially the aerodrome operator, opening themselves up to critique. Each exercise should be designed to push the system and to result in some kind of failure. And after all that, we ask others to tell us what we did wrong and while we know that it is better to fail in an exercise, it is never easy to openly discuss your mistakes.
images credit: (cc) Brussels Airport (Flickr Account)