What is the definition of ASDA?

The definition of ASDA (Accelerate-Stop Distance Available) refers specifically to the runway plus any stopway length available for an aircraft to stop in the event of an aborted takeoff. This is critical for flight safety, as it indicates the total distance available for the aircraft to accelerate to the point of decision and then safely stop if necessary.

In terms of flight operations, understanding ASDA is essential for pilots to evaluate whether they can safely conduct a takeoff considering the aircraft's performance characteristics and the prevailing conditions. The calculation of ASDA incorporates not only the paved runway length but also any additional area—such as a stopway—that can be used in an emergency.

This understanding helps pilots and operators to ensure they have sufficient distance for safe operations, especially in high-performance aircraft, where decisive and often rapid responses are crucial during the takeoff phase.