Frequency of anti- collision observing responses by solo pilots as a function of traffic denisity, ATC traffic warnings, and competing behavior.

2-hour solo simulated flights in a Convair- 340 were completed by 18 instrument-rated pilots. The amount of other traffic and traffic warnings and clearances were each assigned high and low frequencies; The target could be observed as a burst of light flashes through the windshield when the pilot depressed a button on his control wheel. Statistically significant effects were obtained for traffic clearances, traffic warnings, and the interaction of Clearances x Traffic Warnings and Traffic x Traffic Warnings. Observing response rates were influenced by the frequency of traffic warnings and the level of competing behavior the flying task imposed. Vigilance declined when competing behavior was pre-potent and traffic density and traffic warnings were low.