$ V_ {mcg} $ é a velocidade mínima no solo na qual o controle é possível usando apenas o leme em caso de falha do motor crítico. De FAR Part § 25.149 :
VMCG is the minimum control speed on the ground, and is the calibrated airspeed during the takeoff run at which, when the critical engine is suddenly made inoperative, it is possible to maintain control of the airplane using the rudder control alone (without the use of nosewheel steering), as limited by 150 pounds of force, and using the lateral control to the extent of keeping the wings level to enable the takeoff to be safely continued.
À medida que o centro de gravidade avança, o braço do leme aumenta, melhorando a eficácia do leme. Como resultado, um forward cg resulta em um $ V_ {mcg} $ mais baixo. Esta é a razão pela qual os testes para $ V_ {mcg} $ são realizados no centro de gravidade mais distante possível. De Circular Consultiva 23-8C: Guia de Teste de Voo para Certificação da Parte 23 de Aviões :
For rudder limited airplanes with constant aft c.g. limits, the critical loading for VMC testing is most aft c.g. and minimum weight. Aft c.g. provides the shortest moment arm relative to the rudder thus the least restoring moments with regard to maintaining directional control.
como,
There are variable factors affecting the minimum control speed. Because of this, VMC should represent the highest minimum airspeed normally expected in service.