American Airlines Arrival Slot Allocation System (ASAS)

In early 1989, the system operations control center at American Airlines implemented a network-optimization-based system to help reduce delays imposed by air traffic control. The Arrival Slot Allocation System (ASAS) is an interactive decision support tool that uses a network-based heuristic to help flight dispatch personnel take advantage of flight cancellations to reschedule arrivals into an airport. When bad weather or other unpredictable factors reduce the capacity of the airport or airspace for traffic, the Federal Aviation Administration employs ground-delay programs to hold aircraft at their originating cities. These delays affect airline dependability statistics adversely and inconvenience passengers. In recent years, air traffic control has developed slot-substitution rules that allow airlines to use the arrival slots of canceled flights to reduce delays created by the ground-delay programs. In one year, using ASAS the system operations control center reduced the delays imposed by air traffic control by approximately 345,000 minutes. This translates into $5.2 million savings in direct operating costs for the airline. ASAS also improved dependability statistics for American Airlines by an average of two percent per ground-delay program.