factors also influence the controller's choice to use or not to use automation, although the relative importance of the factors and their interactions are not fully understood.

There is considerable interest in the human factors community in the design philosophy known as human-centered automation, although there is less agreement on its specific characteristics. Several meanings can be discerned; however, the objectives of each view can be undesirable and/or in conflict with one another. Effective human-centered automation requires that these inconsistencies be resolved. The specific means by which the principles are realized in design also remain to be fully articulated.