Starbow flight 104, an ATR 72-500, suffered a runway excursion during takeoff from Accra-Kotoka Airport in Ghana. The captain, being Pilot Flying, was in a hurry to takeoff ahead of the incoming storm, but during the takeoff run from runway 21, the airport was being engulfed in thundery rain. At a speed of about 63 kts, the captain’s seat suddenly moved full backwards violently and shifted to the left. The captain handed over controls to the co-pilot after the inadvertent movement of his seat, which appeared to have occurred around 63 knots. At that time the aircraft was to the left of the centreline and heading approximately 6ø off. The flight crew was not aware that the aircraft was going off the runway during the takeoff until the aircraft was almost at the edge of the runway. The takeoff was then aborted by bringing the power levers to ground idle and the co-pilot tried to maintain directional control with the rudder. However, reverse thrust was not selected. The aircraft reached 94 knots before decelerating gradually and thereafter impacted the inner perimeter fence with both engines running. One passenger suffered serious injuries, four other passengers had minor injuries. Causal Factors 1. Loss of situational awareness on the part of the cockpit crew, leading to runway excursion. 2. Failure by the crew to execute correct procedure in aborting the takeoff. Contributory Factors 1. The rain storm that affected the airfield during the takeoff. 2. Loss of situational awareness in the takeoff process. 3. Inadvertent movement of the captain’s seat. 4. Improper procedure in aborting the takeoff. 5. Poor crew resource management.