Abstract
Purpose :
The global pilot shortage is predicted to worsen as air travel demand increases. Visual medical standards are necessary but not evidenced based, restricting eligible candidate pools, and affecting pilot retention. Our study looks at the effect of visual function on flight performance.
Methods :
Twenty participants (3 female, 17 male), novice pilots (0-300 hours), used the ALSIM AL250 Flight Simulator, to perform various landings. Simulated flights were in good weather. Vision was degraded using Cambridge Simulation Glasses. Visual acuity, contrast sensitivity and stereoacuity were measured at all levels of visual degradation. Group 1(N=10) performed an approach and landing under 6 randomized visual conditions 0, 0.3, 0.48, 0.7, 1.0 logMAR and no-vision. Group 2(N=10) performed a flight circuit with the same visual conditions. Contrast sensitivity and stereoacuity ranged from 1.88 to 0.40 log CS and 20 to 400 arcsec respectively. Trials stopped when pilots completed the flight either by either landing or crashing the plane. Outcome measures included slope of altitude descent, variability of vertical speed, airspeed, pitch (Group 1 N=8), and roll (Group 1 N=8). Data were analyzed using repeated measures one-way ANOVAs followed by TukeyHSD post hoc analysis.
Results :
All no-vision trials crashed; however, all other trials were successful. A significant effect of vertical speed variability and roll with visual condition was seen in both group 1 (F(5,45)=13.79, p<0.05; F(5,35)=25.17,p<0.05) and group 2 (F(5,45)=13.31,p<0.05; F(5,45)=5.72,p<0.05). Group 1 Post hoc analysis found variability of vertical speed and roll was higher for no-vision than all other conditions, which were not significantly different from each other. In group 2, vertical speed variability was significantly higher for no-vision in comparison to all conditions, but 1.0 logMAR. A significant difference in the variability of pitch was found only in group 2 (F(5,45)=18.94,p<0.05). Pitch variability was significantly higher for no-vision than all other conditions, which were not significantly different from each other. No differences were found in slope of altitude descent or airspeed variability.
Conclusions :
With ideal weather conditions, novice pilots landed the aircraft even with considerable visual degradation. Further study is required to determine visual cut-offs for ideal and reduced visibility flight conditions.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.