The Skyvan was used for paradropping flights out of Zell am Zee, Austria. At 13:54 the airplane returned from a dropping flight. With the engines running, 19 skydivers boarded the plane through the rear ramp. The pilot then taxied to runway 25, selected flaps to 30 degrees and commenced takeoff. The friction locks of the throttles were not or not properly set prior to takeoff. Due to the vibration of the airplane the throttles slowly retarded during the takeoff roll. At a VR speed of 65kts the pilot pulled back on the controls and the Skyvan left the ground. Immediately after takeoff the airplane rolled and yawed to the left. The pilot pushed the throttles forward and tried to correct the roll. The airplane now rolled 40 degrees to the right and collided with the ground. UNFALLURSACHEN: Pilot – Unterschreiten der Mindestfluggeschwindigkeit – Fehlbedienung Ausrstung – Wahl eines ungnstigen Startverfahrens (Klappenstellung) Organisation – fehlende Vorgaben beim Betrieb mit zwei Piloten