V1 Decision speed – speed to determine whether to continue or abort the takeoff following a failure of the critical engine. Failure below V1 is an abort, at or above V1 the takeoff is continued.
VMCG – minimum control speed – ground – min speed directional control using primary aerodynamic controls following failure of critical engine with max thrust set in take off config.
VMCA – Minimum control speed – air – min speed a/c can be kept within specified limits of heading and attitude following failure of critical engine in second segment config with t/o thrust applied. Defined with a rearmost CoG, within limits which gives highest value of VMCA.
VR - Speed which rotation is initiated by pilot to achieve V2 at or below 35’ with 1 engine inoperative.
VS – minimum steady flight speed / minimum speed in a stall.
VLO – speed a/c lifts off the ground.
VMIN UNSTICK – min speed a/c will lift off gnd. Done doing testing, over rotated early in take off roll, tail strike normally, held nose high attitude until lift off.
V2 – TOSS – following correct rotation and lift off procedures, allows a/c maintain gradient in climb out. Achieve by 35’.
VREF – Reference speed is the landing speed in a nominated configuration, eg VREF 30 would be the landing speed with flaps at 30°.
VMCG ≤ V1 ≤ VR
VR≥ V1 and 1.05VMCA
V2 ≥ 1.1 x VMCA and 1.2 x VS
VR – such that rotation 10kts below VR will not increase the TODR