Janus CM engine fails low on a self-launch climb

Both occupants of a self-launching Janus CM were killed when its engine stopped in the initial climb and control was lost at low height. The motor glider took off under its own power from Albertville and, in a right turn at about 60 m, the engine stopped; a witness heard it cut out. It descended, pitched down and hit the ground by a motorway. The engine quit when the key coupling the generator rotor to the crankshaft sheared, cutting the ignition; the rotor nut had no threadlocker and had loosened. An earlier repair by an unapproved workshop had fitted pistons from a different Rotax engine, and a required piston check had not been done.

1. Self-launch takeoff: The self-launching Janus CM took off under its own power from runway 23 at Albertville with two on board.
2. Engine stops at about 60 m: In a right turn at about 60 m in the initial climb, the engine stopped; a witness on the ground heard it cut out.
3. Sheared generator-rotor key: The key coupling the generator rotor to the crankshaft had sheared and cut the ignition; its clamp nut lacked threadlocker and had loosened progressively.
4. Unapproved engine work: An earlier repair by an unapproved workshop had fitted pistons from a different Rotax engine, and a required piston check had not been done.
5. Loss of control, ground impact: At low height control was lost and the glider struck the ground beside the A43 motorway; both occupants were killed.