In this article we are going to cover the Takeoff speeds in brief. With sequence we will define V1, VR and finally V2.
V1 speed is the speed beyond which the takeoff should no longer be aborted. Above V1, the takeoff must be continued unless there is reason to believe that the aircraft will not fly. An engine failure identified before reaching VR speed should always result in a rejected takeoff. The rejected takeoff decision before V1 speed is possible to end with a safe stop within ASDA (accelerate stop distance available). If a reject is initiated at a speed above V1, there is high risk of runway excursion.
According to the aeromagazine (Aero_11) of Boeing company: “More than half the RTO accidents and incidents reported in the past 30 years were initiated from a speed in excess of V1.”
VR (Rotation) speed
VR (Rotation) is the speed at which the pilot begins to apply control inputs to cause the aircraft nose to pitch up, after which it will leave the ground. It cannot be less than V1. So again the rejection of takeoff after VR speed likely to result with runway excursion.
V2 is takeoff safety speed. The speed at which the aircraft may safely climb with one engine inoperative. The takeoff safety speed must be attained at the 35 ft. height at the end of the required runway distance.
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