FAA Flight Instructor Airplane (FIA)Performance, Weight and BalanceHard
A pilot must depart from a short runway with 50-ft trees located close to the departure end. To maximize altitude gained over the shortest horizontal distance, the pilot should climb at
- AVx, the best angle-of-climb speed
- BVr, the rotation speed
- CVfe, the maximum flap-extended speed
- DVy, the best rate-of-climb speed
Show answer & explanationAnswer & explanation
Correct answer: A. Vx, the best angle-of-climb speed
Vx, the best angle-of-climb speed, yields the greatest altitude gain per unit of horizontal distance traveled, making it the correct choice for clearing close-in obstacles, whereas Vy maximizes altitude gain per unit of time.
Why the other options are wrong
- B. Vr is simply the speed at which the airplane is rotated for liftoff, unrelated to climb angle.
- C. Vfe is a structural airspeed limit for flap extension, not a climb performance speed.
- D. Vy maximizes climb rate over time, not altitude gained over ground distance.
Vx vs Vy for Obstacle Clearance
Vx (best angle of climb) maximizes altitude gained per unit of horizontal distance and is used for obstacles close to the runway; Vy (best rate of climb) maximizes altitude gained per unit of time.
- Vx: steepest climb angle, best for close obstacles
- Vy: fastest altitude gain over time, best for distant obstacles
- Vx is normally lower than Vy
Memory trick: X marks the Xtra steep angle for close trees