When may reverse thrust be used?

• A. Only on the ground
• B. Only in the air
• C. Only at takeoff
• D. Any time on the ground or in the air

Answer: (A)

Reverse thrust is a ground-based braking aid. It changes the propeller pitch to push thrust forward instead of pulling it backward, which helps slow the airplane after it has touched down. In the PC-12 NGX this capability is intended for use only when the aircraft is on the ground with the main gear in contact with the runway and under supervision of the landing procedures. Using reverse thrust in flight would disrupt the airflow and controllability, risk propeller/engine damage, and isn’t certificated for in-air use. It also wouldn’t be useful during takeoff, when you need forward thrust to accelerate and lift off. So the correct practice is that reverse thrust is used only on the ground.