Astir CS77 stalls in low final turn during outlanding

The pilot of a Grob G102 Astir CS77 was fatally injured in a low-altitude loss of control during an outlanding setup; aircraft destroyed. On the return from Husbands Bosworth, weak thermals and cloud spreadout left the glider unable to hold height. After a last thermal down to ~365 m, the pilot tracked southwest over rising ground and set up downwind for a small field at 60–90 m AGL. A sharp left turn onto final at under 60 m AGL developed into an incipient left spin; the glider hit sloping ground nose-down. Probable causes were late field selection and a final turn below safe height, with downdrafts off the escarpment worsening height loss.

1. Cross-country in weakening thermals: A Grob G102 Astir CS77 single-seat glider was winch-launched from Aston Down on a planned out-and-return cross-country task to Husbands Bosworth, ~110 km to the northeast. The pilot held a Gliding Silver Badge with ~479 h total experience (96 on type) and ~24 h in the last 90 days. The outbound leg cruised at around 1 220 m MSL with several thermalling climbs.
2. Cloud spreadout reduces lift: Surface wind was from the southwest at 18–28 km/h with scattered cloud at ~1 310 m AGL and visibility above 10 km. Pilot reports indicated an area of cloud spreadout (cumulus coalescing into a continuous layer) drifting northeast across the route in the Banbury area, reducing solar input and thermal activity. From 1553 hrs the glider was unable to recover its working height despite further thermalling attempts on the return leg.
3. Field selected late at low altitude: At ~700 m MSL the glider began manoeuvring as if to thermal, then descended to ~580 m before a further attempt at ~460 m. The pilot exited after seven turns at ~365 m, roughly 245 m above local terrain, and tracked southwest over rising ground toward Ratley. The selected field — the only smooth surface readily visible ahead — offered only a ~280 m diagonal into-wind run. Larger fields lay north of the escarpment but would have required looking back over the right shoulder. About half of UK field-landing accidents are attributed to late field selection.
4. Final turn at under 60 m AGL: Over the eastern edge of Ratley the glider turned right at 60–90 m AGL onto a track of ~030°, consistent with a left-hand downwind leg for the selected field. Witnesses saw it flying at low level, probably less than 60 m above local terrain, before a sharp left turn onto the final approach track. Published gliding-club guidance is to make the turn to final at no less than ~90 m AGL; the turn here was made below that margin and possibly too low to complete in controlled flight.
5. Incipient left spin from stall: As the glider was crossing the ridge in a south-westerly flow, a localised downdraft off the north-facing escarpment may have further reduced height. During the sharp left turn the nose dropped and the subsequent flight path was obscured from view by trees. The wreckage attitude at impact (steep nose-down, slight left bank, significant rotational momentum) was consistent with entry into an incipient left spin. The Astir's flight manual notes the wing can drop in turns beyond ~20° of bank at the stall.
6. Pilot fatally injured; glider destroyed: The glider struck sloping ground at the head of a shallow valley on roughly the reciprocal of its last known heading, with a high rate of descent. The fuselage broke immediately forward of the fin and the internal structure as far back as the wing trailing edge was extensively dislocated. The pilot was fatally injured; the impact was non-survivable and no restraint change would have altered the outcome. Examination of the wreckage found no pre-impact defect or control system malfunction, and post-mortem found no medical cause that could have contributed.