The decision speed, V₁, may not be above V_R. The only time a large aircraft would ever be landed back on, would be if a failure was suspected that would prevent the aircraft from flying (a structural failure or a masiive fire). Thus, V_R must not be less than V₁.

Also, if the decision is made to go after an engine failure during take-off, then the asymetric thrust will force the aircraft off the centre line. The pilot will try to keep the aircraft straight with rudder, an aerodynamic force. The rudder effectiveness increases with forward airspeed.

Below the minimum control speed on the ground, V_MCG, the aircraft cannot be kept straight. So, the engine failure speed, V_EF, must be greater than or equal to V_MCG and as V₁ is greater V_EF, it follows that V₁ must be greater than V_MCG by that margin.

The minimum control speed in the air, following an engine failure, is V_MCA, to distinguish it from V_MCG. When operating at V_MCA, following an engine failure up to 5º of bank towards the live engine may be used in addition to the rudder to help keep the aircraft straight.

It would seem obvious to say that the aircraft must be controllable in the air and thus, V_LOF should not be less than V_MCA. But, as the aircraft leaves the ground at V_LOF, the 5º bank cannot be immediately applied with the aircraft technically out of control for a while and V_LOF is not calculated, we only calculate V_R.

The restriction on controllability is therefore applied to V_R and a factor is added to allow for the absence of 5º of bank. The restriction is that V_R must be not less than 1.05 V_MCA.