In practice, both aileron and rudder control input are used together to turn an aircraft, with the ailerons imparting roll and the rudder imparting yaw and also compensating for a phenomenon called adverse yaw. A rudder alone will turn a conventional fixed-wing aircraft, but much more slowly than if ailerons are also used in conjunction. Use of rudder and ailerons together produces coordinated turns, in which the longitudinal axis of the aircraft is in line with the arc of the turn, neither slipping (under-ruddered), nor skidding (over-ruddered). Improperly ruddered (uncoordinated) turns at low speed can precipitate a spin that can be dangerous at low altitudes.