The Regulation of Working Methods as a Function of Work-load among Air Traffic Controllers

Abstract A series of field studies among air traffic controllers is reviewed. It largely concentrated on regulatory aspects of operational behaviour, using a model based on the concept of ‘ economy ’ in the individual's selection of operating procedures. Attention is directed at processes involving reasoning, the receipt and transmission of information, and the division of tasks between controllers at the same station. The basic hypothesis, which is supported by numerous data, is that for a given task and a given controller certain operating procedures are less costly than others; that is, they generate lower levels of load. These procedures will therefore be more and more employed as work demand increases, together with the relaxation of certain, self-imposed, qualitative criteria. This regulatory feedback between work-load and operating methods is used by the controller to avoid the abrupt onset of overload conditions and to delay satiation. For the investigator, these progressive changes in operating procedure can provide indirect indices of load. Several ergonomic consequences of this approach for system design are discussed.