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Assessment of visual cues by tower controllers, with implications for a remote tower control centre

Remote control of airports implies application of cameras to replace direct visual observation from airport control towers by projection of the airport and its traffic in a remote control centre. Remote airport control is an emerging technique with benefits for smaller airports mainly, because it reduces the cost of personnel. Surprisingly, hardly any literature can be found to list the required visual objects and phenomena for tower control, i.e. the visual cues that need to be seen for tower control. The composition and validation of the so-called visual cue list for tower control is the subject of this paper. Tower controller task analysis was used to compose a ‘long-list’ of visual features. The long-list has been presented to a group of operational air traffic controllers to test the need and the circumstances to observe these visual cues. Our analysis shows that most of the visual cues are useful for operational tower control but are not strictly mandatory for applying the rules of the International Civil Aviation Organization.. The requirement for visual image resolution of remote tower control is the second subject of the paper. Our analysis leads to definition of a ‘short-list’ of important safety-related visual objects and phenomena for tower control and the conclusion that state of the art media are just able to provide the required image resolution for visual detection but not for recognition.