FAA Ground School Practice Test

When does P-factor lead to yawing to the left?

1. At low altitudes with low power settings

2. When at high angles of attack

3. During flight maneuvers at high speed

4. When cruising at a constant altitude

The correct answer is: When at high angles of attack

P-factor, or asymmetric thrust, is primarily observed in propeller-driven aircraft, particularly during high angles of attack. When an aircraft is at a high angle of attack, such as during takeoff or slow flight, the descending blade of the propeller on the right side generates more thrust than the ascending blade on the left side. This imbalance in thrust causes the aircraft to yaw to the left. At lower angles of attack, the effects of P-factor are less pronounced, and other factors such as yawing moment from the propeller may not lead to noticeable directional changes. Similarly, in cruising flight at a constant altitude or during high-speed maneuvers, aerodynamic factors and the distribution of forces generally balance out, thereby reducing P-factor's impact. Thus, when the aircraft is operating at high angles of attack, it clearly illustrates how P-factor can lead to a left yawing motion.