What force makes an airplane turn?

• A. The horizontal component of lift
• B. Thrust
• C. Weight
• D. Normal force

Answer: (A)

When the wings are banked, the lift force tilts with the wings rather than pointing straight up. Lift acts perpendicular to the wing surface, so a bank makes part of that lift point toward the center of the turn.

That horizontal component of lift provides the centripetal force needed to pull the airplane into a curved path. The vertical component of lift still balances the airplane’s weight, so altitude can be maintained in a coordinated turn.

Thrust mainly affects speed and drag; it’s not the force that makes the airplane turn. Weight acts downward and is what lift counters, but by itself it doesn’t create the sideways pull. In flight there isn’t a separate sideways “normal” force causing the turn—the turn comes from the horizontal component of lift generated by banking.