The present study examined U.S. Naval aircraft mishap trends between January 1977 and December 1992 using all Class A, B, and C mishaps. Results of this investigation revealed that mishaps attributable to both human error and mechanical/environmental factors have declined steadily over the past 16 years, although mishaps attributed to human error have declined at a much slower rate. For those mishaps attributed to human error, differences were observed between single- and dual-piloted aircraft when phase-of-flight (takeoff, in-flight, landing)

and time-of-day were evaluated. For single-piloted aircraft, in-flight mishaps constituted the highest proportion of mishaps during the day (>55%), while landing mishaps constituted the highest proportion of mishaps during the evening and night (43-65%). For dual-piloted aircraft, no consistent variation was evident for phase-of-flight and time-of-day. In-flight (approx. 55%) mishaps constituted the highest proportion of mishaps across all times of day, followed by landing (approx. 35%), and takeoff (approx. 10%) mishaps. These data support focused rather than global investigations of aviation mishaps.