How many things have to go wrong for two jet airliners to collide in midair out in the middle of nowhere? Looking at the data that’s coming in, the answer seems to be an awful lot. It seems like the list of mistakes starts with the fact that a key air traffic warning system was down for maintenance, one of the air traffic controllers overseeing the airspace where the collision occurred was on break, and the air traffic controllers warned the Russian pilot late and didn’t warn the DHL pilot at all. Both planes were also supposed to have on board collision warning systems, but apparently only the DHL plane had the system. The DHL pilot did the best he could — his collision warning system told him to dive and he wasn’t told any different by air traffic control, which did tell the Russian pilot to dive. It’s easy to think that if any one of the conditions that contributed to the collision were different, disaster would have been averted. I comment on this crash only because I’m somewhat fascinated by failures of complex systems, especially those that have as many safeguards built in as air traffic control.