DG-800 tries to motor away too low and hits the treetops

A DG-800 self-launcher struck treetops short of an outlanding field near Issoire after trying to restart its engine too low; the pilot was unhurt and the glider substantially damaged. Conditions were worse than forecast, and after failing to find lift the pilot picked a field below 100 m. On the turn to final at about 20 m he deployed the propeller to motor away — his usual technique, with the landing as fallback — but eight seconds later the engine had not caught, the extra drag had deepened the sink, and the glider hit 20 m trees. The propeller had come out far below the 400 m manual minimum.

1. Local soaring from Le Broc: The pilot self-launched at 11:49 from Issoire-Le Broc for local soaring; after ~1h15 thermalling and a max altitude of 1580 m, he entered a valley southwest of the field seeking lift.
2. Unfavourable aerology: Conditions were worse than forecast, with low ceiling and weak thermals. After 10 minutes of unsuccessful attempts in the valley, the glider was down to ~611 m altitude, under 100 m AGL.
3. Habitual motor go-around: The pilot's usual technique was to deploy the propeller once established on an outlanding circuit, then start the motor on final like a go-around, landing as a fallback if it failed.
4. Propeller deployed at ~20 m AGL: After turning onto final in the outlanding circuit, at ~20 m AGL the pilot deployed the retractable propeller; the flight manual requires at least 400 m AGL near a landing zone.
5. Sink rises, motor not started: The flight manual states that with the propeller extended and motor not yet running, sink rate at 90 km/h increases by ~2 m/s (~400 ft/min). The deployment sequence takes about 10 seconds.
6. Collision with 20 m treetops: Eight seconds after deployment began, motor not running, the glider struck 20 m treetops short of the field, wing torn off and fin broken. Substantial damage; pilot uninjured.