Unbearable lightness of being a plane

There's a story in the paper today about a local businessman and his wife who died in a light plane crash. Now, I don't mean any disrespect to anyone concerned but the phrase "light plane crash" always strikes me as odd. Because, well, planes are heavy. That's why, when they stop working, they crash. They tend not to float, feather-like, towards the ground and get stuck in a big cobweb on a nearby tree, or land on a lake without breaking the surface tension of the water. The term "light plane crash" seems to suggest that it's somehow a less severe version of some fully weighted, gutsy, more substantial plane crash. Or at least something that has fewer calories.