V1 IS NOT A DECISION SPEED

V1 The speed to be used as a reference whether to reject or continue the takeoff.

IMPORTANT : V1 is not a decision speed, V1 is the speed at which first braking action must be applied, therefore the decision to reject the take off must be taken before V1.

V1 -speeds are selected such, that the following applies:

?If an engine failure is recognized before V1, the takeoff must be rejected. A stop can be made within the available accelerate-stop distance without the aid of reverse thrust, provided rejecting actions are initiated at or before V1

?If an engine failure is recognized at or above V1, the takeoff must be continued. A height of 35 ft (Screen height)* will be reached within the available takeoff distance.

?When the V1 value is selected such that, with an engine failure, the required takeoff distance is equal to the required accelerate-stop distance, the takeoff is called a "balanced takeoff " and the takeoff V1 speed a "balanced V1".

?V1 must not be less than VMCG plus the speed gained between the instant at which the critical engine is failed and the instant at which the pilot recognizes and reacts to the engine failure, and not greater than VR and VMBE ( VMCG < V1 < VR & VMBE ).

VMCG : MIN CONTROL SPEED ON GRD

VR: ROTATION SPEED

VMBE : MAX BRK ENERGY SPEED