Measuring Behavior 2005: Hoogeboom and Zon

Radiotelephony understandability verification using a program distributed via Internet

P.J. Hoogeboom and G.D.R. Zon

National Aerospace Laboratory NLR, Amsterdam, The Netherlands

In the continuous strive for increased flight safety levels, an experiment to verify the understandability of aeronautical radiotelephony messages has been conducted. The problem addressed concerns the pronunciation of the one hundred number either as ‘one-zero-zero’ (International Civil Aviation Organization - ICAO - standard) or as ‘one hundred’.

The main problem for this experiment concerns obtaining a sufficiently large number of pilots with different linguistic backgrounds. Pilots are scattered around Europe (or the globe). To overcome the associated financial burdens for travel, a dedicated PC program has been created which guides the pilots through the experiment. The program can be downloaded from the Internet and allows pilots to perform the experiment at their own pace, in their favorite environment and at a moment when they have time. From an experimental point of view, advantages are that participants can conduct the experiment in parallel, reducing the risk that they exchange information, and the reduction of the total experiment duration (multiple participants).

The program consists of an explanatory session, a training session including actual performance feedback, the main test with two sessions including rating forms (e.g. NASA TLX), and two questionnaires (biographic and topic related).

The participant needs to perform a domain relevant flying task using a simplified autopilot. Each time the participant receives an audio message from the simulated controller (10 different voices) directed to the own aircraft, the cleared values like heading, speed, altitude and communication frequency have to be selected using a graphically displayed keyboard. The flight status is displayed on a Primary Flight Display. A secondary task - analogous to the monitoring task from the NASA Multi Attribute Task Battery (MATB) - is added to ensure a workload level in accordance with what is experienced during normal flight.

The paper includes the description of the program, some of the obtained experimental results, and the lessons learned with the set-up of this experiment like program creation, randomization of experimental conditions, recruiting participants, and the analysis of the reactions.

Paper presented at Measuring Behavior 2005 , 5^th International Conference on Methods and Techniques in Behavioral Research, 30 August - 2 September 2005, Wageningen, The Netherlands.