What happened
On March 26, 2011, a Mooney M20, registration D-ERAM, was performing a private flight when it veered off the runway at Cuneo airport. During the landing sequence on runway 03, the aircraft experienced a sudden yaw to the right immediately after the nose wheel made contact with the ground. This maneuver caused the aircraft to exit the right side of the runway. There were no injuries to the pilot and no damage was sustained by the aircraft. The incident resulted in the airport being closed for approximately thirty minutes.
The investigation
Investigators conducted visual and functional inspections of the aircraft's landing gear, braking system, and steering mechanisms, finding no mechanical malfunctions or anomalies. However, an examination of the cockpit controls revealed that the rudder trim was set to the "take-off" position. This specific setting is designed to offset the left-turning torque produced by the propeller during takeoff by pre-positioning the rudder and nose wheel steering toward the right.
Additionally, meteorological data from METAR reports indicated a significant shift in wind conditions between 13:00 UTC and 15:00 UTC. The wind had transitioned from 020° at 5 knots to 110° at 9 knots, introducing a notable component from the right and rear during the landing phase.
Findings
- The rudder trim was left in the take-off position, which introduced a rightward bias to the rudder and nose wheel steering.
- The pilot likely centered the rudder pedals after the main gear made contact, failing to account for the existing rightward trim offset.
- The sudden rightward deviation was likely exacerbated by a crosswind/tailwind component shifting from the right.