The great miracle in the US Airways flight landing in the Hudson River and all 155 people surviving--and not just surviving, but apparently without any significant injuries determined so far--is that it validates about 70 years of constant striving in the commercial air safety world to learn from mistakes and never become complacent.

The worst complacency in the face of difficulty was in the space shuttle program. Richard Feynman showed awfully conclusively that NASA had developed a thick skin about doing the impossible. Do the impossible often enough, and you assume that you cannot fail. The culture of success led to accept the result of all that hard work and ongoing vigilance as the status quo, and then built more risk on top of that.

Feynman wrote in an appendix to the official Challenger disaster study report that the criteria by which safety for shuttle flights were judged non-risky enough to launch would be changed to ensure a lower probability of failure would result. "Let us make recommendations to ensure that NASA officials deal in a world of reality in understanding technological weaknesses and imperfections well enough to be actively trying to eliminate them."

Amazingly, the FAA and commercial airlines, along with pilot and flight attendant unions, and Congress and the president and courts, have managed to create an environment in which there is enough knowledge of what works, and a culture of never assuming that what worked last time will work this time unless checked in the same fashion, that commercial flight has become incredibly safe.

In the US Airways flight:

You might note, too, that some of the first details coming out of the aftermath of the flight are about recovering as much data about the crash: first, to see what more can be done to prevent bird intake into engines (though quite a lot has been done), if that's the cause; second, to learn what the pilot and passengers did right to incorporate that into flight and crew training, and into passenger information.

Flying is an inherently dangerous act rendered remarkably safe, with a margin of safety vastly more than anything else we do in regular life, because of the assumption that each time, every act must be carried out intentionally.

More: Great quote in an AP story today from an NTSB member, Kitty Higgins: "Miracles happen because a lot of everyday things happen for years and years and years," she said. "These people knew what they were supposed to do and they did it and as a result, nobody lost their life."