Incidence and Cost of Orientation-Error Accidents in Regular Army Aircraft Over a Five-Year Study Period: Summary Report

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Incidence and Cost of Orientation-Error Accidents in Regular Army Aircraft Over a Five-Year Study Period: Summary Report

W. C. Hixson / E. Spezia

This report is a summary account of the results of a joint Army/Navy study of orientation-error aircraft accidents that occurred in Regular Army aviation over a five-year period. Statistical data are presented that indicate spatial disorientation in helicopters is a significant flight hazard very comparable in magnitude to the threat generally accepted as being present with military operation of fixed wing aircraft. Of the total number of accidents that occurred in rotary wing (RW) aircraft over the study period, orientation error accounted for approximately 7.4 percent of the total, 16.5 percent of the total number of fatal accidents, 15.8 percent of the total number of fatalities, 9.4 percent of the total number of nonfatal injuries, and 10.3 percent of the total aircraft dollar damage costs. The risk associated with an orientation-error accident that occurred in a RW aircraft was also most significant in that 35 percent of these accidents were fatal. The study also provides quantitative data to validate the high accident risk (not combat losses) of combat-oriented flight operations. For aircraft of all types, the mean accident rate (accidents per 100,000 flight hours) in Vietnam was approximately 2.4 times greater than the rate elsewhere for accidents of all types, 2.1 times greater for pilot-error accidents, and 3.3 times greater for orientation-error accidents. (Author)