Aviation accidents are two-phased. Human factors clearly dominate the first and most important incident phase. Although aircraft accident rates are being reduced gradually, there is a percentage increase in man-caused accidents due to improved equipment, reliability, and operations monitoring capability. The continuing dialogue between federal regulatory agencies and the National Transportation Safety Board has helped force change in design and in regulation and, in turn, improve safety in the four categories of civil aviation. Authority and accountability must always remain firmly linked together if there is to be continued safety improvement, because safety depends on people.