What happened
On August 17, 2004, a Cessna 172 M, registration F-GLEO, was performing a repositioning flight to the private airfield of Saint-Crépin-et-Carlucet. The flight was initiated to move the aircraft from Sarlat to a more secure location due to approaching thunderstorms. After conducting a reconnaissance flight at 1,500 feet, the pilot joined the left-hand downwind for runway 24 at 1,000 feet.
During the final approach, the pilot configured the aircraft with the third notch of flaps. As the aircraft reached short final, the pilot realized that the approach speed and descent gradient were too high, estimating that the touchdown point would be delayed by approximately 100 meters. Upon touchdown, the pilot applied heavy braking. Due to the recent rain and the uphill 3% gradient of the unpaved runway, the wheels locked, causing the aircraft to skid across the wet grass. The aircraft eventually came to a stop in a hedge several meters beyond the end of the runway, resulting in damage to the propeller and right wing.
The investigation
The investigation focused on the pilot's decision-making process and the aircraft's behavior on the unpaved surface. The investigators examined the weather conditions, which included scattered clouds at 500 feet, broken clouds at 2,000 feet, and nearby cumulonimbus clouds with active rain showers. The pilot noted that the pressure to move the aircraft quickly due to the approaching storm contributed to a sense of stress. Furthermore, the investigation looked into the pilot's approach profile, noting that the presence of trees near the runway threshold led to a steeper descent path.
Findings
- The primary cause of the excursion was the pilot's failure to execute a go-around despite recognizing an unstable approach.
- The pilot's decision to maintain the approach was influenced by haste and stress related to the need to secure the aircraft before the storm arrived.
- The use of heavy braking on a wet, unpaved surface led to wheel lock-up and a subsequent skid.
- The pilot adopted an excessively steep descent gradient to clear obstacles (trees) near the runway threshold.