ABSTRACT
Introduction The US Federal Aviation Administration (FAA) oversees the largest, safest, and most complex aviation system in the world, relying on a workforce of highly trained air traffic control specialists who interact with an environment of radar, computers, and communication facilities to maintain the safety and efficiency of the system. In fiscal year (FY) 2000 alone the US air traffic system handled 166,669,557 operations. Calculated as a percentage of facility activities, the operational error (OE) rate per 100,000 activities increased from .60 in calendar year (CY) 1999 to .69 in CY00 and .74 in CY01, then declined by 11 per cent to .66 in CY0210 (FAA, 2003a). Although air traffic declined after the events of 11th September 2001, the OE rate reflects the continuing need to identify mitigation strategies.
