The pilot in command intended a private flight with two passengers from Leipzig/Halle to Arnsberg/Menden. At 08:35 hrs , he received the taxi clearance for runway 26 while standing on apron one. The Cessna taxied via taxiways N, W1 and C to the CAT III taxi stop in taxiway A7. While turning into taxiway A7, the Cessna 525 was cleared to taxi onto runway 26 at 08:45:05 and cleared for take-off 15 seconds later. At 08:46:39 hrs, the pilot reported by radio that he had left the runway. Tyre tracks led diagonally across runway 26 approx. 100 m into the side safety strip as an extension of the centre line of taxiway A7. After a left turn, where first the nose landing gear and a little later the left main landing gear broke at a service road, the tracks ran parallel to runway 26. On this stretch, the aircraft turned about 180ø around its vertical axis, skidded tail-first and came to a standstill at the level of taxiway A6. The nose and left main landing gear were torn off. The left wing was severely damaged and the underside of the fuselage was deformed at the level of the nose wheel.