What happened
On October 10, 2005, a privately operated Dyn’Aéro MCR 4S was conducting an endurance flight for engine break-in and verification purposes. The aircraft, registered F-WVSG, departed at approximately 13:30 and remained in the vicinity of the Dijon Darois aerodrome for roughly four and a half hours, operating between flight levels 90 and 100.
Upon landing on the unpaved runway 20, the pilot perceived that the aircraft was deviating to the right. In response, the pilot applied left rudder. This input caused the aircraft to veer left, eventually exiting the runway and coming to a stop approximately 70 meters from the runway edge. The excursion resulted in damage to the propeller, engine cowling, and nose gear.
The investigation
The investigation focused on the pilot's actions during the landing phase and the physiological state of the crew. Investigators examined the aircraft's flight path and the physical evidence left on the runway. While the pilot reported an initial rightward deviation, tracks on the runway showed no significant rightward movement; instead, the tracks indicated a leftward deviation at an angle of approximately 45 degrees.
Investigators also reviewed the pilot's recent activity and physical condition. The pilot had been living in a caravan for the three weeks preceding the accident and had flown 20 hours and 30 minutes in the six days prior to the event. Furthermore, the investigation looked into the physiological effects of flying at higher altitudes (FL 100) and the impact of dehydration and fatigue on pilot performance.
Findings
- The primary cause of the excursion was excessive rudder input applied by the pilot.
- The pilot was experiencing significant fatigue and difficulty concentrating at the end of the flight.
- The pilot's focus was diverted by a specific objective, leading to a lack of situational awareness during the landing.
- Physiological stressors, including dehydration and the physical effort required for the body to adapt to flight levels near 10,000 feet, likely contributed to decreased vigilance.