In what flight condition is torque effect the greatest in a single-engine airplane?

The greatest torque effect in a single-engine airplane occurs during low airspeed, high power, and high angle of attack. This specific flight condition amplifies the torque effect because the airplane is operating in a phase where its aerodynamic efficiency is reduced and the engine output is maximized.

In this scenario, low airspeed contributes to a less effective airflow over the control surfaces, which can make it more challenging to maintain coordinated flight. At high power settings, the engine produces maximum torque, which translates into a significant tendency for the airplane to roll in the opposite direction of the propeller's rotation. This rolling tendency is pronounced because the increased power exacerbates the effects of torque, creating a more noticeable need for corrective action through control inputs.

Additionally, the high angle of attack increases the overall lift being generated but also can enhance the effect of the engine’s torque because the aircraft may be closer to its critical angle of attack. As the angle of attack increases, the yawing and rolling moments from the torque are more pronounced, requiring the pilot's active management of the aircraft's orientation and stability.

In contrast, the other flight conditions listed result in reduced torque effects, either due to lower engine output or more favorable airflow over the wings, which lessens the overall impact