What is the role of V-speeds such as V1, VR, and V2 on the 787 takeoff?

• A. They are used for takeoff and are determined from weight and conditions.
• B. They are fixed values unrelated to weight.
• C. They are only relevant for landing performance.
• D. They are selected by the captain randomly.

Answer: (A)

V speeds are takeoff performance targets that are not fixed numbers. They are calculated from the airplane’s weight, configuration (like flap setting), and environmental conditions (temperature, altitude, runway conditions). V1 is the speed at which a decision must be made to continue or abort the takeoff; beyond V1 there may not be enough runway to stop safely. VR is the rotation speed at which the nose is lifted to transition to a climb, and V2 is the minimum safe speed for takeoff after an engine failure, ensuring adequate climb performance. On the 787, these speeds are derived from current performance data and vary with weight and conditions, guiding the takeoff and initial climb.