ABSTRACT
After almost 100 years of service, commercial air travel can look back with some satisfaction on an excellent safety record. Nonetheless, rapid growth in air traffic is threatening the ability of air traffic control (ATC) systems worldwide to handle traffic efficiently and safely. Moreover, even if the airline accident rate remains at its current low value, it is estimated that on average one major commercial airline accident will occur somewhere in the world every week simply because of the increased volume of traffic. The recent call for a fivefold improvement in safety by the Gore Commission in the US was clearly motivated by the need to avoid the public outcry that would result from such an outcome.
