Visual detection of commencement of aircraft takeoff runs

Among other things, airport control towers should be sited so that controllers can readily detect whether an aircraft cleared for takeoff has commenced its takeoff run. The detection of movement is not well enough understood to enable confident prediction that a particular site for a tower will enable commencement of takeoff run to be easily observed. A field study was undertaken to establish detection times for commencement of takeoff run by groups of trained and trainee air traffic controllers and untrained observers. It was found that the mean response of observers occurs when the aircraft is displaced about 5' of arc, a value essentially independent of observer experience, observation distance, aircraft velocity, and the clarity with which the aircraft can be seen. Binoculars reduce the mean response time and response variability, although not as much as might be expected. Domains within which control towers can be located to enable detection of takeoff runs within 2 s and 4 s are defined.