Field data and laboratory studies conducted in the 1990s reported that the rate of pilot readback errors and communication problems increased as controller transmissions became more complex. This resulted in the recommendation that controllers send shorter messages to reduce the memory load imposed on pilots by complex messages. More than 10 years have passed since a comprehensive analysis quantified the types and frequency of readback errors and communication problems that occur in the operational environment. Hence, a content analysis was performed on 52 hours of pilot and controller messages that were transmitted from 5 of the busiest terminal radar approach control (TRACON) facilities in the contiguous United States between October 2003 and February 2004. Of importance was the finding that the number of pilot readback errors increased as the complexity and number of ATs in ATC messages increased — especially when pilots were performing approach tasks as compared with departure tasks. To limit the occurrence of communication problems and misunderstandings, controllers should be encouraged to transmit shorter and less complex messages.
(2007). Effects of Message Complexity and Message Length on the Production of Pilot Readback Errors. 2007 International Symposium on Aviation Psychology, 558-563.