DECU,
Among other things the minimum control speeds are related to the thrust available. The greater the thrust from the live engine, the greater will be the yawing moments caused by asymmetric thrust, following single engine failure. So anything that increases thrust will increase VMCG and VMCA. If air temperature decreases, the air will contract, causing its density to increase.
Thrust is proportional to mass airflow through the engine, so the increased air density will increase the thrust available at any given engine RPM. this will increase both VMCG and VMCA.
V2 must be at least 1.1 x VMC, so when decreasing temperature increases VMC, it will also increase the minimum acceptable value of V2 (V2 Min).
VR must be such that the aircraft can accelerate to V2 by screen height. The increased thrust at lower temperatures, increases the acceleration rate and so decreases the minimum value of VR.
Last edited by Keith.Williams.; 5th April 2002 at 19:26.