In flight, what does V(sub x) indicate?

V(sub x) is known as the best angle of climb speed. This speed allows an aircraft to gain the maximum altitude over the shortest horizontal distance. It is particularly important during takeoff and initial climb phases when an aircraft may need to clear obstacles in its path.

Flying at V(sub x) ensures that the aircraft achieves the best climb gradient, which is the vertical distance gained in relation to the horizontal distance traveled. This is particularly useful for pilots when they are departing from an airport with obstacles in the vicinity, as it helps to maintain safety and efficiency.

Understanding V(sub x) is crucial for pilots as it directly affects the performance of the aircraft in terms of terrain clearance and ensuring a stable climb path during critical phases of flight.