What does Vx denote in aviation terms?

Vx, or best angle of climb speed, is a critical performance metric in aviation that indicates the speed at which an aircraft can gain the greatest altitude over a given horizontal distance. This speed is crucial during takeoff and initial climb because it allows a pilot to clear obstacles while maximizing the altitude gained per distance traveled.

When flying at Vx, the aircraft achieves a steep climb gradient, which is particularly important when departing from airports located near terrain or obstacles. This speed ensures that the aircraft is operated efficiently for obstacle clearance, contributing to safety during critical phases of flight.

The other choices refer to different performance metrics:

• The best rate of climb speed, which is the speed that maximizes altitude gain over time, is denoted as Vy.

• Landing approach speed is the speed maintained during the final approach for landing, and cruise speed refers to the speed maintained during normal flight operations. Each of these speeds serves distinct purposes in flight operations but does not represent the concept of Vx.