What is Takeoff Decision Speed (V1)?

• A. The maximum speed allowed during takeoff.
• B. The minimum speed at which the aircraft can rotate.
• C. The speed at which the aircraft becomes airborne.
• D. The calibrated airspeed on the ground at which the pilot decides to continue or discontinue the takeoff.

Answer: (D)

Takeoff Decision Speed is the speed on the takeoff roll at which you must decide whether to continue the takeoff or abort it. It’s a calibrated airspeed computed from the airplane’s performance data for the given weight, configuration, runway length and condition, wind, slope, and ambient conditions. The idea is that if an engine failure occurs before reaching this speed, you should be able to stop safely within the remaining runway (accelerate-stop distance); if the failure happens at or after this speed, there isn’t enough runway to stop safely, so you continue the takeoff. This speed is distinct from rotation speed (the speed you start to pitch up) and from liftoff speed (the speed at which the airplane becomes airborne).