What happened
On June 4, 2006, during a regional gliding competition at Hausen am Albis, an accident occurred involving a Maule M-7-235 towplane, registration HB-KDM, and an ASW 27 glider, registration HB-3269. During the takeoff sequence, the towplane began to taxi forward to extend the tow rope. As the rope tightened, the unbraked glider rolled forward, inadvertently running over the slack rope.
Following this, the towplane pilot momentarily halted the aircraft to wait for another glider to clear the runway. Seeing the rope had been run over, two ground assistants moved in front of the glider's wings with the intention of pushing the aircraft back to re-tension the rope. Simultaneously, the start coordinator, unable to see the assistants from his position, issued a radio command to proceed with the takeoff. The towplane pilot, who did not hear the subsequent emergency 'stop' command due to poor radio clarity, applied full power. The moving glider wings struck both assistants, causing one serious injury.