Which speed is known as the takeoff decision speed?

The takeoff decision speed is referred to as V1 speed. This speed is critical during the takeoff phase of flight, as it represents the maximum speed at which a pilot can decide to abort the takeoff safely. Beyond this speed, the aircraft is committed to taking off, and the pilot cannot safely return to the runway without risking an accident.

Understanding V1 is essential for pilots and dispatchers because it directly impacts safety in the event of an engine failure or any significant issue during the takeoff roll. At V1, the aircraft is accelerated with the intention of becoming airborne, and if an engine failure occurs before reaching V1 speed, the pilot can safely stop the aircraft on the remaining runway.

The other speeds mentioned—like Vmo, which refers to the maximum operating speed, Vr, which is the rotation speed for liftoff, and Vef, which is the engine failure speed—serve different purposes in the takeoff and flight regimen, but V1 is uniquely identified as the takeoff decision speed. Hence, V1 is critical for ensuring that pilots make informed decisions during this crucial phase of flight.