CNN is reporting the pilots of the private plane involved in the 737 midair collision that was the subject of yesterday's story have been arrested. I'm not particularly surprised at this, but expect to see more. There are a very large number of safeguards, both automated and procedural, designed explicitly to avoid the situation of two airplanes trying to occupy the same piece of sky. A screwup of this magnitude nearly always involves a chain of failures, all of which must line up just right for disaster to happen. The private plane's pilots are in the firing line right now. I just hope it's not a giant political coverup for some sort of systemic or high-level flight control screwup.