A rudder travel limiter, or rudder limiter, is a controlling device in an

aircraft An aircraft is a vehicle that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engine ...

used to mechanically limit the maximum

rudder A rudder is a primary control surface used to steer a ship, boat, submarine, hovercraft, aircraft, or other vehicle that moves through a fluid medium (generally air or water). On an aircraft the rudder is used primarily to counter adve ...

deflection.

Background

An aircraft rudder is a

flight control surface Aircraft flight control surfaces are aerodynamic devices allowing a pilot to adjust and control the aircraft's flight attitude. Development of an effective set of flight control surfaces was a critical advance in the development of aircraft. Ea ...

used to control rotation around its vertical axis, known as yaw, which is especially important during takeoff, landing, and emergency conditions. Rudders are typically found within the

vertical stabilizer A vertical stabilizer or tail fin is the static part of the vertical tail of an aircraft. The term is commonly applied to the assembly of both this fixed surface and one or more movable rudders hinged to it. Their role is to provide control, s ...

of the aircraft. Excessive use of rudder can exceed the

ultimate load In engineering, the ultimate load is a statistical figure used in calculations, and should (hopefully) never actually occur. Strength requirements are specified in terms of limit loads (the maximum loads to be expected in service) and ultimate l ...

of the vertical stabilizer, causing structural failure. For this reason, modern airliners and fly-by-wire aircraft often include a system to prevent excessive rudder deflection. The rudder travel limiter in the

Airbus A300-600 The Airbus A300 is a wide-body airliner developed and manufactured by Airbus. In September 1967, aircraft manufacturers in the United Kingdom, France, and West Germany signed a memorandum of understanding to develop a large airliner. West G ...

is controlled by the Feel and Limitation Computers (FLC) maintaining sufficient yaw control within the entire

flight envelope In aerodynamics, the flight envelope, service envelope, or performance envelope of an aircraft or spacecraft refers to the capabilities of a design in terms of airspeed and load factor or atmospheric density, often simplified to altitude. The t ...

and limiting excessive lateral loads on the rudder and

Notable Accidents

A fault with the rudder travel limiter was involved in the crash of

Indonesia AirAsia Flight 8501 Indonesia AirAsia Flight 8501 was a scheduled international passenger flight operated by Indonesia AirAsia from Surabaya, Java, Indonesia, to Singapore. On 28 December 2014, the Airbus A320 flying the route crashed into the Java Sea, killing ...

. The design of the rudder travel limiter on the

was cited as a contributing factor to the crash of American Airlines Flight 587. In addition to a low rudder pedal sensitivity compared to other aircraft, the A300-600 had a variable stop design, contrary to earlier iterations of the A300 which used a variable ratio design.

References

Aircraft controls {{component-aircraft-stub