AN ANALYSIS OF SINGLE-ENGINE, FIXED-WING, LIGHT AIRCRAFT ACCIDENTS

Statement of the Problem. The purpose of this study was to analyze the interaction between outcome variables (the results of accidents) and condition variables (those conditions present at the time of mishap) involving single-engine, fixed-wing, light aircraft.;A theoretical model was developed for further analysis of accident factors of single-engine, fixed-wing, light aircraft so that objective rather than subjective knowledge may be applied to the development of safety standards in the operation of this type aircraft.;Hypothesis Tested. The statistical hypothesis to be tested in this study states that there are significant three-way interactions, which can be demonstrated by a log-linear model, existing between outcome variables and condition variables as collected by the National Transportation Safety Board.;Procedure. A five-year census of single-engine, fixed-wing light aircraft accidents, as collected on the aircraft accident analysis sheet by the National Transportation Safety Board, was examined by means of the multiway frequency tables, the log-linear model in the BMDP Biomedical Computer Program, P-Series. It was an ex post facto study without controls which utilized the collected data by dividing the information into outcome variables (results of accidents), known as the dependent variables, and the condition variables (conditions present at the time of accident), known as the independent variables. All data utilized were from the mandatory list of reportable items on the aircraft accident analysis sheet of the National Transportation Safety Board.;Conclusions. (1)Increased age was found to coincide with critical environmental conditions. (2)Commercial pilots with flight instructor's ratings demonstrated the best overall performance under critical operating conditions. (3)Weather conditions exhibited a significantly higher severity index in conditions of less than three-statute-mile visibility and less than a 1,000-foot AGL ceiling. (4)The highest severity index occurred during the in-flight portion, and the most accidents occurred during landing.;Recommendations. (1)There is a need to collect more specific aircraft accident data for the purposes of analysis. (2)Aircraft accident data should simplify statistical applications. (3) A wide variety of normalizing data should be collected so that a greater variety of statistical techniques may be applied. (4)Researchers should consider man, machine, and environment simultaneously when assessing implications. (5)New studies of this type, using more qualitative data, would be valuable.