Date of Award

Spring 2013

Access Type

Thesis - Open Access

Degree Name

Master of Science in Human Factors & Systems


Human Factors and Systems

Committee Chair

Jason Kring, Ph.D.

First Committee Member

Amy Bradshaw Hoppock, Ph.D.

Second Committee Member

Dan Macchiarella, Ph.D.


Throughout the course of any flight, pilots and air traffic control (ATC) are in constant radio communication regarding the position and route of the aircraft. Effective pilot-ATC communication helps to increase safety by increasing the situation awareness of both the pilot and controller. In the current pilot-ATC communication system, auditory messages are sent back and forth between the pilot and controller. The nature of these auditory messages makes them highly susceptible to memory and information processing limitations. This effect is magnified when dealing with pilots who have learned English as a second language (ESL) as people have more difficulty processing information in their second language (L2). The study examined the effect of using mixed modality or redundant (auditory and visual) ATC messages in the cockpit on ESL pilots. The study employed a 2 x 2 mixed design with primary language as a between-subjects factor (monolingual, English speaking pilots vs. ESL pilots) and message modality as a within-subjects factor (auditory only vs. auditory and visual). Forty pilots, 20 in each language condition, conducted enroute and approach flight maneuvers while responding to pre-recorded ATC messages taken from real ATC transmissions. Each pilot was exposed to 20 clearances, ten visual and ten mixed. The researchers recorded each pilot's readback and assessed the response time and accuracy of each transmission. Each response time and accuracy score were calculated into an average for each participant based on clearance type. The responses were also calculated into a composite score that determined an accuracy to speed ratio. The results of the study indicated that both groups performed significantly better in the mixed modality; however, the study did not reveal any significant group differences.