What must VMCA be in relation to V2?

VMCA, or Minimum Control Speed with the critical engine inoperative, is the minimum speed at which the aircraft can maintain controlled flight with one engine inoperative. This speed is crucial for pilots, especially during takeoff and climb phases, when an engine failure can occur.

For an aircraft to maintain control with one engine inoperative, VMCA must be significantly lower than V2, which is the takeoff safety speed. V2 is the speed that ensures the aircraft can climb safely after an engine failure. If VMCA were higher than V2, the aircraft would not maintain controllability after an engine failure at the V2 speed, which would pose a serious safety risk in the event of such a failure.

Thus, it is vital for VMCA to be less than V2, ensuring that pilots have the required control authority and can safely operate the aircraft following an engine failure at or above V2 during takeoff.