Background
The MD-81 arrived from Zurich at 22:09 and was parked at gate 2 overnight with outside temperatures around +1°C. Approximately 2550 kg of fuel remained in each wing tank. The aircraft was scheduled to depart Stockholm for Copenhagen at 08:30, and the early morning temperature had dropped to -0°C. During the night and early morning, clear ice had formed on the upper side of the wings, but this was not detected by the ground crew member who inspected the forward part of the wing. The aircraft was then fueled with 1400 kg of fuel and was ready for de-icing at 08:30, which was performed using 850 liters of Type I fluid. After de-icing, the mechanic did not check for clear ice on the upper side of the wings, having previously found none.
Events During Flight
The flight was cleared to taxi to runway 08 and took off at 08:47. After 25 seconds, at an altitude of 1124 feet, bangs, vibrations, and jerks were perceived in the aircraft, caused by a surge in the No. 2 engine. The engine was throttled down, but the throttle control simultaneously switched to an automatic mode (Automatic Thrust Restoration, or ATR) that increased the throttle setting with altitude, intensifying the surging. The No. 1 engine surged 39 seconds later, though the flight crew did not notice. An attempt to engage the autopilot at 2616 feet failed. At 76 and 78 seconds into the flight, both the No. 2 and No. 1 engines failed after the stage 1 stators of both engines broke up due to high loads from the surges. The aircraft was climbing through 3206 feet at 196 KIAS at that moment. A fire warning for the No. 1 engine at 91 seconds prompted the crew to activate the fire extinguishing system. A SAS captain traveling in the passenger cabin recognized the problems and hurried to the cockpit to assist the flight crew.
Emergency Landing
The aircraft was in a gliding left turn. While descending through 420 meters, still in clouds, the assisting captain gradually extended the flaps. The flaps were fully extended at 1100 feet (340 meters), and the aircraft broke through the clouds at 980–820 feet. A field in the direction of flight was selected for an emergency landing. The landing gear was selected down, and Stockholm control was informed about the imminent crash-landing. The MD-81 contacted trees at 121 knots, and a major portion of the right wing broke off. The aircraft then struck sloping ground tail-first and slid along the ground for 110 meters. The fuselage broke into three pieces, but there was no fire.