Rudder

The rudder is a movable flight control surface attached to the vertical stabilizer (fin) at the rear of the aircraft. It controls movement around the yaw axis — the left-right rotation of the aircraft's nose. The pilot controls the rudder using foot pedals in the cockpit.

Primary uses of the rudder include:

• Coordinated turns: Applying rudder to counteract adverse yaw during banking
• Crosswind landing: Aligning the aircraft with the runway during the flare (sideslip or de-crab technique)
• Engine-out control: Counteracting the asymmetric thrust after an engine failure — this is the most demanding rudder input and defines the minimum control speed (Vmc)
• Slip and skid correction: Maintaining balanced flight

On large transport aircraft, the rudder is typically divided into upper and lower sections for redundancy, each powered by independent hydraulic systems. Rudder limiters automatically reduce maximum rudder deflection at high speeds to prevent structural overload — a lesson learned from the American Airlines Flight 587 accident in 2001.