Mac, I have learnt a lot from your posts. But I must hit the 'wooooaaah' button.You assert that most aviation accidents are due to lack of communication. This is simply not true. A short visit to any accident investigation database (e.g. NTSB) will soon dispel this. Yes, communication in the cockpit is important, and CRM is a vital part of what is now described as TEM ( threat and error management). I agree with your analogy of an unnatural environment, which is why airlines have developed the procedures they use and require from their flight crews. These mitigate the possibility of serious consequences. Communication with other crew and ATC is an integral part of the safety net, but to identify it as the major cause of accidents is just not factual.