Which statement best describes Vmc?

• A. It is the minimum speed at which the aircraft can be controlled with the critical engine inoperative.
• B. It is the speed at which maximum range is achieved.
• C. It is the stall speed with both engines operative.
• D. It is the minimum safe speed with all engines functioning.

Answer: (A)

Vmc is the speed where you can still maintain control of a twin-engine airplane when the most adversely affected engine (the critical engine) has failed. Losing that engine creates a strong yaw tendency because the surviving engine’s thrust has to counteract the asymmetry, and the rudder and other controls must counter both yaw and any resulting roll. Below this speed, you may not be able to keep the aircraft straight or level even with full rudder and proper control inputs; above this speed, with the remaining engine at takeoff power and proper control input, directional control is achievable.

So the statement correctly defines Vmc as the minimum controllable speed with the critical engine inoperative. This isn’t about maximum range, it isn’t the stall speed with both engines operating, and it isn’t a generic “minimum safe speed with all engines functioning.”