Twin Astir multiple ground impacts after pilot impaired in winch abort

A Grob G103 Twin Astir II on a solo winch launch at Seighford was substantially damaged; the pilot was seriously injured. At ~60 m AGL a loud bang was heard and, assuming a weak-link break, the pilot pitched down aggressively to abandon (dust rose under negative g). The cable then back-released from the belly hook. The pilot then became briefly impaired — conscious but unable to control pitch or airbrakes; the cause was not established. The glider oscillated in pitch, struck the ground, bounced and impacted twice more; the fin and tailplane broke away. Investigators cited the brief impairment of unknown origin.

1. Solo winch launch from front seat: A Grob G103 Twin Astir II was on a solo winch launch from Seighford, flown from the front seat; the glider had recently been fitted with new energy-absorbing seat cushions.
2. Loud bang at ~200 ft AGL: Launch began normally with the glider pitching nose-up. At about 200 ft AGL the pilot heard a loud bang and assumed the winch cable's weak link had broken.
3. Pitch-down to abandon (judged excessive): The pilot lowered the nose to abandon the winch launch. He observed dust from the cockpit floor rising into his vision due to negative g and judged that his pitch-down input was excessive.
4. Cable back-released from belly hook: The winch cable released from the belly hook; inspection found the weak link intact and the cable sound, consistent with a back-release under rearward load.
5. Pilot briefly impaired, cause unknown: Shortly after the abandonment the pilot became briefly impaired, remaining conscious but unable to control the glider's pitch or open the airbrakes; the cause was not established.
6. Pitch oscillation, airbrakes retracted: With the pilot impaired and unable to operate controls, the glider was observed to oscillate in pitch with airbrakes retracted.
7. Multiple heavy impacts, fin detached: The glider struck the ground level, bounced back into the air, and impacted twice more; the fin and tailplane broke away in the final impacts, and the pilot was seriously injured.