Ground loop (aviation)

A ground loop in aviation refers to an uncontrolled, often violent, rotation of an aircraft around its vertical axis while on the ground. It typically occurs during landing or takeoff, particularly in tailwheel (conventional landing gear) aircraft, though it can also affect tricycle-gear aircraft under certain circumstances.

The primary cause of a ground loop is instability stemming from the location of the main landing gear behind the aircraft's center of gravity (CG). This configuration means that any deviation from the intended direction of travel can create a moment arm, causing the aircraft to swing further in that direction. This can quickly escalate into an uncontrollable turn.

Contributing factors to ground loops include:

• Pilot technique: Improper rudder control, insufficient airspeed, and abrupt control inputs can all exacerbate instability.
• Crosswind: A crosswind component makes it more difficult to maintain directional control and can initiate a ground loop.
• Runway conditions: Slick or uneven runway surfaces can reduce the effectiveness of braking and steering.
• Aircraft design: Aircraft with shorter wheelbases or higher centers of gravity are generally more susceptible to ground loops.

Recovery from a ground loop is often difficult, and the best approach is prevention through proper training and adherence to recommended procedures. Pilots flying tailwheel aircraft must develop a high level of skill in rudder control, particularly during ground operations. In the event of a ground loop, immediate corrective actions, such as applying opposite rudder and braking, may help to mitigate the severity of the situation, but success is not guaranteed. Ground loops can result in significant damage to the aircraft.