What happened
On August 8, 2016, an instructor and a student were participating in a cross-country gliding flight involving four single-seat gliders. The flight began at Amboise-Dierre, intended to be a triangular route of approximately 280 kilometers. As the afternoon progressed, a weather front moved in from the west-northwest, terminating thermal activity and prompting the crew to divert to Romorantin-Pruniers.
Following a brief stop, the group attempted a return flight to Amboise via aero-tow. The Schempp Hirth Janus CT, registration D-KLAY, was towed in the third position. At approximately 19:40, the instructor released the glider at an altitude of roughly 1,450 meters. Shortly after release, the aircraft encountered rain, which reduced horizontal visibility and degraded the glider's glide ratio. Additionally, the headwind component increased. Realizing that reaching Amboise was no longer feasible, the instructor diverted toward the private airfield at Montrichard.
Unable to locate the intended diversion airfield, the instructor identified a field for an emergency landing. Due to the reduced visibility, several hay bales in the first field were only detected late in the approach. The instructor aborted the approach at an altitude between 50 and 70 meters to maneuver toward a second field to the left. While attempting to align with this new field, the pilot identified an east-west power line but failed to detect a second power line running north-south, perpendicular to the flight path. The glider struck an electrical pole and a hedge before impacting the ground, resulting in the destruction of the aircraft.
The investigation
The BEA examined the flight sequence, the meteorological conditions, and the aircraft's performance. The investigation focused on the instructor's decision-making regarding the diversion, the impact of the weather front on visibility and glide performance, and the identification of obstacles during the final approach. The investigation also reviewed the technical capabilities of the Schempp Hirth Janus CT, noting that while it is equipped with a retractable Solo 2350 engine, the engine was not utilized during the final phase of the flight.
Findings
- The instructor made the decision to depart Romorantin-Pruniers despite knowing that weather conditions were deteriorating.
- The instructor's decision to divert was made too late, driven by an inadequate estimation of the glider's performance under the prevailing weather conditions.
- The pilot was unable to identify the chosen diversion airfield.
- The emergency landing was conducted at a very low altitude, preventing a proper reconnaissance of the landing site.
- The presence of rain significantly reduced horizontal visibility, which contributed to the late detection of obstacles, including hay bales and power lines.