Evaluation in Context: ATC Automation in the Field
INTRODUCTION Certification is defined as attesting as certain (Flexner & Hauck, 1983). “Certainty” however may be a rare commodity when the introduction of new technology into an existing system can “…destroy the blanket of established know-how” (Rasmussen and Goodstein, 1988; p. 179). It is impossible to foresee all emergent properties and interactions between system components and their implications. A complete set of requirements and criteria for safe and efficient system functioning is difficult, if not impossible, to define in advance of system implementation. Once the system is in an operational environment, requirements may need to be rejuvenated due to our imperfect foresight and lack of understanding. Christensen (1958) has referred to this dilemma as the “omnipresent criterion problem”.