Ventus 2b and Mooney M20J collide mid-air; glider pilot bails out

The pilot of a Ventus 2b was lightly injured in a mid-air collision with a Mooney M20J near Auenstein; the glider was destroyed and the Mooney substantially damaged. The glider was cruising west at 1,285 m MSL behind two others; the Mooney was climbing on autopilot on a familiarisation flight. A strut and magnetic compass hid the glider from the Mooney crew for the last 5 seconds; the glider pilot saw the Mooney peripherally at 50 m. The Mooney had no collision-warning system, and the Ventus's Flarm could not see its Mode-S transponder. After impact the Ventus rolled uncontrollably; the pilot jettisoned the canopy and parachuted clear.

1. Cruise west of Aare, gliders in trail: At 11:55 LT on 6 June 2013 a Ventus 2b launched on aerotow from RWY 08 of Birrfeld (LSZF) and released near Chestenberg at about 1,100 m MSL. After thermalling to about 1,400 m MSL the pilot followed two other gliders west toward the Gisliflue, some 150–200 m below them. Simultaneously a Mooney M20J had left Lommis at 11:55 on a familiarization flight (instructor right, pilot under check left); after routing past Whiskey and VOR Trasadingen it turned south at about 880 m MSL near Linn and began climbing on autopilot to clear the Birrfeld area.
2. Mooney crew view obscured 5 s before: From at least 5 seconds before impact the converging Ventus was hidden from the Mooney crew by a cockpit-roof strut and the magnetic compass mounted in their line of sight. With the autopilot flying the climb, the crew did not detect the glider in time to react.
3. Flarm can't see Mode-S Mooney: The Mooney carried only a Mode-S transponder and no collision-warning system; the Ventus's Flarm could not receive Mode-S signals and gave no electronic warning. SUST recommended (Nos. 498 and 499) that BAZL standardise compatible collision-warning systems for general aviation.
4. Both crews scan elsewhere: After crossing the Aare westbound the glider pilot turned his head north to assess the weather over the Black Forest. The Ventus was at about 160 km/h ground speed, the Mooney at about 220 km/h, on converging tracks at similar altitude. About a minute later the glider pilot caught the Mooney in his peripheral vision at roughly 50 m, gear up, closing from the right — too close to avoid.
5. Mid-air at 1,285 m MSL: At 12:18:52 LT the two aircraft collided over Auenstein at 1,285 m MSL, the Ventus slightly below the Mooney's left wing. The Ventus's primary structure was damaged enough that elevator and rudder inputs no longer had any effect; the Mooney's left wing skin and integral fuel tank were ruptured.
6. Pilot bails out, inverted: The Ventus rolled to the right and pitched nose-down. After verifying that the elevator and rudder were inoperative, at about 1,200 m MSL the pilot jettisoned the canopy and released his harness. The glider was already inverted; he fell out of the cockpit and deployed the rescue parachute, which opened immediately. He steered the chute toward a forest clearing on the south side of the Gisliflue and landed lightly injured, waiting about an hour for the police to find him.
7. Glider destroyed; Mooney lands: The unmanned Ventus crashed in wooded terrain and was destroyed. The Mooney crew levelled, called Zurich Information, and flew back to Lommis; with the fuel selector on the intact right tank, the punctured left tank did not deny fuel supply. The Mooney landed at Lommis at 12:55 LT.