During flight, what must be true to maintain a steady level turn at constant airspeed?

• A. Increase thrust/power and angle of attack
• B. Increase thrust and decrease angle of attack
• C. Decrease thrust and increase angle of attack
• D. No change in thrust and angle of attack

Answer: (A)

In a steady, coordinated level turn at constant airspeed, you must generate more lift to both support the aircraft’s weight and provide the centripetal force for the turn. When you bank, the lift vector tilts, so the vertical component that counters weight is L cos(phi). To keep level flight, L must increase to balance W, giving a load factor n = 1 / cos(phi). Because speed is held constant, you raise lift by increasing the angle of attack, which raises the lift coefficient. However, increasing lift also increases drag (especially induced drag), so you need more thrust (power) to maintain the same airspeed.

That combination—more thrust/power and higher angle of attack—is what keeps the turn steady at the same speed. If thrust isn’t increased, drag will slow the aircraft; if angle of attack isn’t increased, lift won’t meet the higher demand and the aircraft won’t stay level in the turn.