In aviation terminology, a rejected takeoff (RTO) or aborted takeoff is the situation in which it is decided to abort the takeoff of an airplane. There can be many reasons for deciding to perform a rejected takeoff, but they are usually due to suspected or actual technical failures, like an engine failure such as a compressor stall occurring during the takeoff run.
A rejected takeoff is normally performed only if the aircraft's speed is below the critical engine failure speed (sometimes called decision speed) known as V1 , which for larger multi-engine airplanes is calculated before each flight.The Federal Aviation Administration defines V1 as: "the maximum speed in the takeoff at which the pilot must take the first action (e.g., apply brakes, reduce thrust, deploy speed brakes) to stop the airplane within the accelerate-stop distance. V1 also means the minimum speed in the takeoff, following a failure of the critical engine at VEF, at which the pilot can continue the takeoff and achieve the required height above the takeoff surface within the takeoff distance." Below the decision speed, the airplane should be able to stop safely before the end of the runway. Above the decision speed, the airplane may overshoot the runway if the takeoff is aborted, and, therefore, a rejected takeoff is normally not performed above this speed, unless there is reason to doubt the airplane's ability to fly. If a serious failure occurs or is suspected above V1 but the airplane's ability to fly is not in doubt, the takeoff is continued despite the (suspected) failure and the airplane will attempt to land again as soon as possible.
Single-engine aircraft will normally reject any takeoff after an engine failure, regardless of speed, as there is no power available to continue the takeoff. Even if the airplane is already airborne, if sufficient runway remains, an attempt to land straight ahead on the runway may be made. This may also apply to some light twin engine airplanes.
Before the takeoff roll is started, the autobrake system of the aircraft, if available, is set to the RTO mode. The autobrake system will automatically apply maximum brakes if throttle is reduced to idle or reverse thrust during the takeoff roll.