Originally Posted by AZFlyer

Yep. And on a related note, one of the things that the youngsters aren't taught to keep an eye out for during the summer walk around is the telltale patch of condensation on the aircraft skin where the cold air duct has come loose or is leaking. It's easy to overlook, but when you spot it, you can suddenly be the hero of the day for getting the cold air fixed on a plane.