Definition
The runway length declared as available and suitable for the acceleration and deceleration of an aircraft aborting a takeoff. It is the total distance from the start of the takeoff roll to the end of the surface usable for stopping, and it includes any stopway at the far end of the runway.
Plain English
The total length on the ground a pilot can use to speed up for takeoff and then stop again if they decide not to fly. It includes the runway plus any paved area at the end designed for stopping.
Context Anchor
Seen in runway declared distance information and takeoff performance planning, especially when checking whether a runway is long enough for a safe rejected takeoff.
Derivation
Built from three plain-English ideas: 'accelerate' (speed up), 'stop' (decelerate), and 'distance available' (how much runway you actually have). The phrase comes from a set of declared distances airports publish so pilots can calculate takeoff performance precisely.
Why Pilots Care
It determines whether the runway supports a safe abort at the planned takeoff weight and directly affects maximum allowable takeoff weight.
Intuition Check
Do not read “available” as “the pavement that appears to be there.” Here it means the distance the airport has officially declared usable for this specific takeoff-and-stop purpose.
Example Sentence 1
Before departure, the pilot checked the ASDA for Runway 27 and confirmed the aircraft could accelerate to V1 and stop within that distance.
Example Sentence 2
At this airport the accelerate-stop distance available included the stopway, allowing a higher takeoff weight than the runway alone would support.