Twin Astir strikes trees landing out after a final glide through a ridge's lee

On a ferry flight from Hranice to Frýdlant, the pilot of a Twin Astir was seriously injured and the glider destroyed when its left wing caught trees in a forced landing and it struck the ground nose-first. About 4.5 km out and 650 m above the airfield, the pilot glided in across the Ondřejník ridge in a strong south-westerly wind. In the lee the glider sank at what he estimated as 10 to 20 m/s. Turning north towards fields, he could reach only a small meadow behind trees; the wing caught the treetops and the glider swung round into the ground. The report found he had probably underestimated the wind over the ridge when deciding to glide in.

1. Aerotow ferry from Hranice: The pilot was aerotowed from RWY 23 at Hranice at 18:00 behind a Z-226 to ferry the glider to Frýdlant, and released west of the Ondřejník ridge at 1,000 m MSL.
2. Final glide across Ondřejník: After climbing to 1,200 m MSL, about 4.5 km out and 650 m above the airfield, the pilot set off on a final glide across the Ondřejník summit, roughly on the extended runway line.
3. Strong south-westerly wind: The forecast surface wind was 200–290° at 26 to 37 km/h, gusting 46 to 65 km/h. The report found the pilot had probably underestimated its direction and strength over the ridge.
4. Extreme sink in the lee: Beyond the summit the glider entered extreme sink in the ridge's lee; the pilot estimated 10 to 20 m/s, with the variometers at full scale. Frýdlant was now out of reach.
5. Turn north towards fields: After losing about half the height, the pilot turned north towards an area with fields, but with the sink continuing could reach only a small meadow behind a row of trees by a road junction.
6. Left wing in the treetops: Near the ground the sink eased, but the glider passed through the upper branches of trees about 10 m tall at the meadow's southern edge, and the left wingtip caught them.
7. Nose-first impact, glider destroyed: Slowed by the branches, the glider swung about 180° left and struck the soft ground nose-first at a steep angle, crushing the front cockpit; the pilot was seriously injured.