Left turning tendencies are caused by which combination of effects?

• A. High Power; High Angle of Attack; Low Airspeed
• B. Low Power; Low Angle of Attack; High Airspeed
• C. Wing Loading
• D. Torque Reaction; Corkscrew Effect; Gyroscopic Precession; Asymmetric Propeller Loading (P-Factor)

Answer: (D)

Left turning tendencies come from four propeller-related effects that create a yaw to the left, especially when power is high and the aircraft is at a high angle of attack with relatively low airspeed. The engine’s torque reaction tends to rotate the airplane opposite the direction of the propeller’s rotation; for a typical clockwise-rotating prop seen from the cockpit, this produces a left yaw. The corkscrew effect describes the sideways yaw produced by the spiraling slipstream of the propeller as it interacts with the fuselage and tail. Gyroscopic precession is the reaction of the spinning propeller when you change pitch; the gyroscope tends to yaw the nose in the direction dictated by the precession, often contributing to a leftward moment during pitch changes. Asymmetric propeller loading, known as P-factor, occurs at higher angles of attack because the descending blade has a higher effective angle of attack and produces more thrust on the right, pushing the nose left. Together these effects explain why left turning tendencies arise; other factors like wing loading don’t directly cause this yawing moment.