Which statement best describes the relationship between tailplane stalls, power, and flaps?

• A. Will be aggravated by adding power when the flaps are extended
• B. Will be alleviated by adding power when the flaps are extended
• C. Unrelated to power and flaps
• D. Only affected by throttle position, not flaps

Answer: (A)

Tailplane stall happens when the horizontal stabilizer can’t produce the required downward force because its angle of attack has reached the stall. Extending the flaps increases wing lift and changes the aircraft’s pitching moment, so more tail-down force is needed to hold the nose down. That raises the tailplane’s angle of attack toward its stall limit. Adding power brings more flow over the tail via the propeller slipstream, further increasing the tailplane’s angle of attack and reducing its margin before stalling. With flaps out and power applied, the tailplane is even more likely to stall, reducing elevator effectiveness and leading to a pitch change. So, adding power when the flaps are extended aggravates tailplane stalls.