What should the position of the cowl flap be when the aircraft is on the ground?

The correct position of the cowl flap when the aircraft is on the ground is fully closed for cooling. This configuration allows the engine to reach and maintain optimal operating temperatures efficiently while the aircraft is stationary. By keeping the cowl flaps fully closed, airflow through the engine is minimized, which helps retain heat and allows the engine to warm up if it requires it for optimal function during taxiing or before takeoff.

In contrast, leaving the cowl flaps open could lead to unnecessary cooling, which may not be ideal, particularly if the engine needs to be at a certain temperature for proper operation or if it has just been started and is still warming up. Therefore, the fully closed position is essential for managing engine temperatures effectively while on the ground.