Control surface failures are thankfully rare, but easily some of the most stressful malfunctions a pilot can face. Occurring mostly during takeoff, a control surface failure compounds an already tense moment, adding to the issues and factors a pilot already faces in such a situation. Thankfully, by keeping a clear head and taking prompt action, the pilot can prevent an accident from occurring.
One type of control surface failure involves losing control of the rudder. The rudder, or vertical stabilizer, provides yaw control to the aircraft. Yaw is the direction the aircraft is pointing on its horizontal plane, either left or right. The rudder is connected to rudder pedals in the cockpit via either mechanical linkage, or electronic cabling in fly-by-wire systems. These systems can become disconnected, or the mechanical actuation of the rudder itself can become blocked by rust, corrosion, or foreign debris if it isn't regularly inspected and cleaned.
During takeoff, the rudder is used to counteract the various forces that push an aircraft left during takeoff. In propeller-driven aircraft, torque from the engine propeller rotating clockwise forces the left side of the aircraft down towards the runway, which causes the left tire to have more friction on the ground that the right tire, and makes it veer to the left.
P-factor, or asymmetric propeller loading, occurs when the downward moving propeller blade takes a larger "bite" out of the air than the upward moving blade, and typically occurs if the aircraft has a tailwheel configuration, or is flying at a high angle of attack.
Gyroscopic precession occurs when force is applied to a spinning disc, in this case a propeller. Then force is applied to a part of the disc (in this case the movement of air) the effect of that force is felt 90 degrees in the direction of the rotation of the disc.
Lastly is the spiralling slipstream that is caused by the air moving behind and active propeller, which eventually wraps its way around the fuselage to hit the tail of the aircraft on its left side, which produces a yawing motion.
When dealing with rudder failure, the first and most important thing to do is to stay calm. Don't lurch, fly gently, and don't try to force the aircraft. The rudder trim tab can provide a degree of yaw control if your rudder features one, which can alleviate the situation. Another unconventional method, and one that should only be attempted if the pilot and any passengers are firmly strapped into their seats, is to open the doors of the aircraft. Open doors disrupts the airflow around the aircraft, and creates an approximation of yaw control. Entering a forward slip can also help manage directional control as well, but the pilot needs to be sure to manage their altitude and add more power to prevent a spin from occurring.
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