What happened
On July 18, 2019, a Centrair Pegase C 101 glider, registration F-CGOX, was conducting a local flight near Morcenx, France. The pilot had departed from Bordeaux Léognan Saucats earlier that afternoon, utilizing thermals to maintain altitudes between 1,000 and 1,400 meters. After reaching Rion-des-Landes, the pilot noted deteriorating atmospheric conditions and a lack of usable lift, prompting a return toward Morcenx.
As the aircraft's altitude dropped to approximately 500 meters, the pilot decided to perform a field landing. The pilot selected a large, plowed field and performed several turns to lose altitude while scouting the landing area. During the final approach, the glider's landing gear struck a medium-voltage power line located at the edge of the field. The impact caused the aircraft to flip, resulting in a violent impact on its back. The pilot sustained one injury, and the glider was destroyed.
The investigation
The investigation, supported by FLARM data and pilot testimony, focused on why the obstacle was not identified during the reconnaissance phase. The accident site was a plowed field bordered by medium-voltage lines with poles spaced roughly 100 meters apart. The investigation examined the visibility of the electrical infrastructure and the environmental conditions at the time of the accident.
Findings
Investigators determined that the pilot failed to detect the power lines during the approach, which prevented any necessary trajectory adjustments to avoid the obstacle. Several factors contributed to this lack of detection:
- The low contrast between the utility poles and the color of the plowed field made them difficult to distinguish.
- The sun was nearly at its zenith, resulting in minimal shadows being cast by the poles, which otherwise could have served as a visual cue.
- The inherent difficulty in detecting overhead lines in flight, as identification often relies on spotting the supporting poles rather than the wires themselves.