Time delays in air traffic control communication loop: Effect on controller performance and workload

The impact of digital technology-induced delays in the pilot-controller communications on air traffic controllers' performance and workload was investigated in 2 experiments manipulating systemic audio delay (AD) and variable pilot delay (PD). Vectoring accuracy (Experiment 1), lateral separation between 2 aircraft on converging tracks (Experiment 2), and subjective workload (NASA-Task Load Index) were measured. In Experiment 1, the effect of AD was measurable but not statistically significant; PD reduced accuracy and resulted in earlier turn initiations. In Experiment 2, both AD and PD significantly reduced separation between aircratts. Short communication delays, however, did not substantially degrade controller performance in the experiments.