Experiment 1.
(drs j.p.krol (airline pilot/exp.neuropsychologist))

Radar controllers workload as a function of pilots workload.

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Purpose of the experiment was to investigate the relationship between air traffic controllers workload and pilots workload. The experiment is of the explorative type, seeking to establish if the BCG task could be used in the radar controllers situation to measure spare information handling capacity.

The experiment was conducted at Schiphol airport (Amsterdam) under IFR at night.


Material and methods.

An aerodrome traffic circuit pattern was flown six times by an aircraft, chartered for the experiment.

The aircraft was under radar control with the pilot on instruments following the controllers instructions.

It was assumed that the radar controllers workload would be different in selected flight phases.

The flight phases can thus be regarded as the experimental treatments.

They included level flight . (LF), take off (TO) and approach (AP) in order of supposedly ; increasing workload for the radar controller (and the pilot). A reference phase with the aircraft on the ground was included.(R).

The dependent variable was the radar controllers BCG task performance. In this experiment the stimuli were high or low tones. The required response was to press a pedal under the controllers left foot when the tone was low and a pedal under his right foot when the tone was high.




Results are shown in figure 1.
scien15.gif (3410 bytes)


The controllers BCG performance is clearly related to the flight phases in the predicted manner.



The controllers performance with the aircraft in level flight is better then in the reference phase (R). There may be two reasons for this. Firstly it is pointed out that with the aircraft in level flight the controller has practically nothing to do ( their are no other aircraft in the circuit). Secondly, the reference phase was recorded before the experiment. It must be assumed that learning has the effect of improving BCG performance in the later stages.

It is felt that the experiment has demonstrated the possibility of using the BCG as a possible workload measure for air traffic controllers on the job.




To further refine the measurement procedure in some ground controlled approaches the pilot was placed under a paced aural distraction stress of 30 tones per minute, randomly varying between high and low.

He had to respond by pressing one of two buttons on his control column and knew he had to overshoot when making more then one error per minute (the author -who is also an airline pilot- supervising).

At the same time the radar controller talking him down had to press foot pedals in response to high and low tones but in an unpaced condition (to measure his spare information handling capacity ).

It was predicted that the approaches with the pilot under distraction stress would deteriorate and that this would reduce the radar controllers spare information handling capacity.

However, although flying performance deteriorated considerably under distraction stress, this did not affect the radar controllers spare information handling capacity.

(The radar controllers BCG performance was mixed electronically with the picture on the radar screen to provide a simultaneous record of ongoing events in the air and his spare information handling capacity).

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Copyright J. P. Krol ©