What is the primary purpose of VMCG?

The primary purpose of VMCG is to define minimum control speed on the ground. VMCG refers to the minimum speed at which a multi-engine aircraft can be controlled during the takeoff roll in the event of an engine failure. This speed is crucial because if an engine fails while the aircraft is accelerating on the ground, maintaining control becomes significantly more difficult at speeds lower than VMCG. Understanding and adhering to this speed ensures that the pilot has enough control authority over the aircraft to steer it down the runway and avoid potential disasters.

In contrast, the other options deviate from the core concept of VMCG. Ensuring sufficient speed during ascent, establishing maximum cruising speed, and determining landing configuration parameters pertain to flight dynamics and operational performance but do not relate specifically to the minimum control speed on the ground.