WESTERN RESEARCH COMPANY, INC. Medical and Health Related Research Since 1984
Flight Simulator Use to Study Pilot Performance
Western Research has been developing a program to study alcohol effects on pilot safety utilizing a flight simulator, the Elite PC-ATD, which is an Federal Aviation Administration (FAA) approved full function flight simulator for which actual flight training time can be logged in fulfillment of FAA pilot certification regulations. We have developed software tools that allow for the logging of a battery of aircraft and navigation parameters at 1 second intervals throughout the course of a flight plan. The effects of alcohol ingestion, which has many consequences similar to pilot fatigue, has been readily observed and measured quantitatively in our laboratory. This is consistent with numerous studies in the literature that have demonstrated the validity of flight simulators in studying pilot physiological responses [10, 24].
Data processing and analysis takes several forms: 1) each flight can be scored against a check list for errors and incidents, 2) quantitative flight data (obtained from our logging software) can be plotted for evaluation against FAA Practical Test Standards, and 3) anomalous events in the flight data can be plotted for evaluation. Results using these protocols we have obtained appear below.
For example, flight scores for test flights with or without elevated blood alcohol level (BAC) were monitored using aircraft manufacturer provided checklists; the flight was scored based on pilot adherence to the checklist and points were applied to the flight score for each deviation from approved procedure. Points were weighted for relative importance of each checklist item. Examples of two such evaluations obtained in our flight simulator laboratory are shown in Figure 1a and b.
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Figure 1: Flight test scores for pilots performing at the extremes of the subjects tested; pilot (a) scored nearly flawless flights at BAC = 0.0, but significantly worse at elevated; pilot (b) had a sober baseline score noticeably worse than pilot a and performed very poorly with increased BAC. In each instance the highest score accrued to a serious accident that would not be expected of either pilot in a sober state. |
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Practical Test Standards
The FAA has established Practical Test Standards (PTS) for aircraft flight states and maneuvering limitations to which pilots are required to adhere for purposes of safety and flight certification (for example, holding level altitude +/- 100 ft or magnetic heading +/- 10 degrees). These provide a meaningful measure of pilot performance and, for example, we have examined pilot conformity to several PTS protocols (including altitude holding, magnetic heading holding, and altitude gain or loss in turns, among others) both with and without elevated BAC levels. A typical example of our results for such comparisons is shown in Figure 2a and b.
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Figure 2. Corresponding flight segments for a single pilot; this stage of flight was to be flown straight and level at 3500ft MSL with PTS allowing deviations of ± 100 ft. Graph (a) is a sober flight; graph (b) is at BAC = 0.09. Sober, the pilot deviated from PTS 2.9% of the flight; intoxicated he exceeded PTS 38.0% of flight. |
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