decreases, because VMCG is expressed in IAS, which decreases with constant TAS and decreasing density.
increases, because VMCG is related to V1 and VR and those speeds increase if the density decreases.
increases, because at a lower density a larger IAS is necessary to generate the required rudder force.
decreases, because the engine thrust decreases.
In simple words, VMCG is established as being the lowest speed at which rudder effect alone is sufficient to regain and maintain directional control after a sudden engine failure.
The major factor that affects VMCG is the difference in engine thrust. VMCG will therefore be lower at higher airport elevations and at a higher OAT, due to the associated lower thrust. Conversely, VMCG will be higher at lower airport elevations and at a lower OAT.
If conditions are hot, high and humid the air is less dense. This reduces thrust and, consequently, when you lose the critical engine on take-off, there is less yawing effect from asymmetric thrust than there would be in denser air.
Your Notes (not visible to others)