Rejected takeoff after the takeoff decision speed 'V ', Boeing B737 ...

APPENDIX B: V-SPEEDS
Definitions of V-speeds according to the US Federal Aviation Administration (FAA) and European
Aviation Safety Agency (EASA) are:
V 1
Maximum speed in the takeoff at which the pilot must take the first action (e.g., apply brakes,
reduce thrust, deploy speed brakes) to stop the airplane within the accelerate-stop distance. V 1
also means the minimum speed in the takeoff, following a failure of an engine at which the pilot can
continue the takeoff and achieve the required height above the takeoff surface within the takeoff
distance.
V R
Rotation speed.
Takeoff safety speed.
V 2
Other definitions:
V 1
Maximum speed at which a rejected takeoff can be initiated in the event of an emergency and at
which a pilot can safely stop the aircraft without leaving the runway.
V R
Speed at which the pilot makes a control input, with the intention of lifting the airplane out of
contact with the runway or water surface.
V 2
Minimum speed that needs to be maintained up to acceleration altitude, in the event of an
engine failure after V 1
. Flight at V 2
ensures that the minimum required climb gradient is achieved,
and that the aircraft is controllable.
Current certification requirements and rules require the following speed conditions:
V 1
must not be greater than V R
.
V 2
may not be less than V R
plus the speed gained before reaching a height of 35 feet above
the takeoff surface.
Therefore V 1
is smaller or equal to V R
, which is smaller than V 2
.
Apart from the V-Speeds a high and low speed regime is also distinguished. The low speed regime
is the region where the airspeed is below 80 knots. At 80 knots the flight crew cross check their
instruments. Above 80 knots the aircraft is in the High speed regime.
low speed regime
high speed regime
0 80 V 1
V R
V 2
Figure 13: Schematic overview of the V-speeds and the high and low speed regime.
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