Tailplane stall effects will be aggravated by which condition?

• A. Adding power when the flaps are extended
• B. Reducing power with flaps extended
• C. Maintaining level flight with flaps up
• D. Retracting flaps during icing

Answer: (A)

Tailplane stall happens when the airflow over the horizontal stabilizer is disturbed enough that it can no longer produce the downward force needed to keep the nose down. Extending the flaps makes the wing wake more turbulent and stronger, and adding power sends more propwash and disturbed air back toward the tail. That combination increases the tail’s angle of attack locally and can blanket the stabilizer with disrupted flow, causing it to stall earlier and reducing its downward lift. With less downward force available, the airplane tends to pitch up, which can deepen the stall. So applying power with flaps extended creates the most adverse flow conditions for the tail, making tailplane stall effects worse.