Why should control surfaces be locked when an aircraft is parked?

• A. To prevent corrosion
• B. To prevent damage from the wind
• C. To prevent theft
• D. To simplify maintenance

Answer: (B)

When parked, open control surfaces can be moved by even light winds, placing dangerous loads on hinges, pushrods, and attachment points. Locking them keeps the surfaces in a safe, neutral position, preventing gusts from causing movement that could bend or damage the empennage or linkage. Gust locks or other securing devices are used to hold the surfaces steady, reducing the risk of wind-induced damage. Deterrence of theft can be a side benefit, but the main purpose is to protect the aircraft from wind damage while it’s on the ground.