Calif A-21S turnback without altitude check — fence and solar panel impact

A Caproni Calif A-21S crashed in a turnback after early tow release at Aspres-sur-Buëch (Hautes-Alpes); both occupants were injured and the glider destroyed. At ~30 m AGL the towplane had brief engine irregularities; the glider pilot released the cable and immediately turned back without checking altitude or airspeed. The right wing struck the fence of an adjacent solar-panel field; the glider crashed into the panels. BEA cited an altitude misjudgement (no altimeter check, plateau-edge depth illusion) and unfamiliarity with alternative outlanding fields following a recent move without safety briefing.

1. Aerotow initial climb: The two-seater glider began aerotow from RWY 18 at Aspres-sur-Buëch (LFNJ) — a plateau airfield at 830 m elevation with the runway descending 15 m start-to-end and a valley extending in the runway axis. At ~100 ft on initial climb, the glider was reaching the end of the runway near the plateau edge.
2. Towplane engine irregularities: The towplane pilot detected engine irregularities at ~100 ft (right tank running low). He pitched down to preserve airspeed and switched to the left fuel tank; nominal power was restored within 2-4 seconds.
3. Pilot's 3.5-year flying gap: The glider pilot (66, glider licence since 2008, ~700 h) had not flown October 2020 to June 2024. He had two refresher flights with an instructor (5-8 July), a check flight with an examiner (14 July), and three PIC flights for ~8 h before the accident — the last on the day before.
4. No briefing on new airfield: BEA contributing factor: when the pilot relocated to Aspres-sur-Buëch in March 2024, there was no safety briefing. He had planned to scout the area for vachable fields but didn't. Without prior knowledge of nearby fields, he could not factor them into his emergency decision-making.
5. Cable release + immediate turnback: Seeing the cable slacken and the towplane descend (recalling a past tow accident at Bagnères-de-Luchon 2020), the pilot released the cable and immediately initiated a right turn to land contre-QFU on the runway, without checking the altimeter or airspeed. BEA: wrong altitude estimation contributed — the plateau-edge view of the valley below distorted depth perception.
6. Right wing strikes perimeter fence: During the low right turn, the glider's right wingtip struck the perimeter fence of an adjacent photovoltaic field bordering the airfield to the west of RWY 18/36. The contact destabilised the glider.
7. Collision with solar panels: The glider hit the ground, slid, and embedded itself in the first row of solar panels. Glider destroyed; pilot and passenger injured.