LS8-e neo outlands on cross-sloped field, wing strike then tree

An LS8-e neo made an outlanding in the Thorame-Basse valley; the pilot was seriously injured and the aircraft destroyed. After launch from Sisteron-Vaumeilh and a climb to 2,863 m, the pilot descended. Entering the valley in lee subsidence, spirals failed to regain lift. After losing 200 m he picked a field judged slightly uphill — a nearby FFVP safe landing area was not used. Final at ~150 km/h; on flare the lateral slope was first recognised — main wheel and left wing then contacted the ground. The glider bounced, rolled to the end of the field, and struck a tree. BEA cited the unrecognised cross-slope with the safe area not used.

1. Mountain flight from Sisteron-Vaumeilh: DG-LS8-e neo (electric self-launching glider, HB-2550) on a local mountain flight. Pilot 72 yo, SPL since 2007, 1,420 h total, 1,140 h on LS8, 19 h in last 3 months; ~85% of flights in high-mountain regions, typically from Schänis (LSZX, Switzerland), Münster (LSPU), or Nötsch (LOKN, Austria); had previously flown 11 flights / 48 h around Sisteron. Aerotow takeoff at 13:55 from Sisteron-Vaumeilh, heading east; max altitude 2,863 m at 14:50:53. Weather: WNW wind 7-10 kt with 15-20 kt gusts near ground, visibility >10 km, low-to-moderate turbulence, 12 °C.
2. Lee subsidence in Thorame-Basse valley: From 15:04 (at 2,700 m) the glider began losing altitude at ~-0.7 m/s mean. At 15:27 the pilot entered the Thorame-Basse valley at 1,672 m. Météo-France analysis: NW wind 20-30 kt at the 2,300 m ridge summit ~5 km NW of the accident site created lee subsidence in the valley; rabattants (downdrafts) of low intensity but significant for soaring.
3. Spirals fail to regain altitude: The pilot did spirals in the valley to try to gain altitude but could not regain lift; he continued to lose height in -0.5 to -3 m/s sink. He stated that the electric motor (capable of ~1 m/s climb at 95 km/h optimum) did not seem appropriate in strong sink.
4. Outlanding decision after 200 m loss: At 15:33 (at 1,492 m), after losing 200 m, he decided to outland. He picked a field he judged to be slightly uphill, did more spirals as a final attempt to find lift, then began final.
5. Field cross-slope unrecognized: BEA: the mountain environment likely made horizon estimation and field-slope assessment difficult. The Glider Pilot Manual states: 'a sloped/dévers field is to be avoided, it is a guarantee of a cheval de bois (ground loop)'; soft-contoured reliefs are hard to read from above. The pilot recognized the field's lateral slope only during the flare.
6. FFVP safe landing nearby, pilot unaware: The FFVP 'Guide des aires de sécurité dans les Alpes' lists a safe landing area LF0459 'Thorame-Basse' a few hundred meters from the chosen field, with notes (land NW, right half of field, NW wind brings turbulence and violent rotors). The pilot was unaware of this safe area and did not use the FFVP guide.
7. Fast final, wing strike on flare: Short final pitch was ~20% slope at -7.5 m/s mean vertical speed; ground speed ~150 km/h. The flight manual recommends ~90 km/h on approach; in gusts the Glider Pilot Manual recommends VOA = 1.3 × Vs + ½ × max wind = ~122-131 km/h. The indicated airspeed was ~100 km/h per the pilot; ground speed of 150 km/h suggests a tailwind component on final. Main wheel then left wing contacted the sloped ground.
8. Bounced, rolled, struck tree, destroyed: Glider bounced, lost direction control, rolled to the far end of the field, struck a tree on its trajectory and came to rest in an adjacent lower field. Pilot seriously injured; aircraft destroyed. BEA contributing factor: mountain environment likely made horizon and field-slope estimation difficult. BEA safety lessons: study all known safe landing areas, keep GPS/databases current, do not take off without the latest safe-landing-area guide.