Incident
During the takeoff roll, the pilot's seat abruptly slid to the full back position. This caused the pilot's feet to lose contact with the rudder pedals, and the airplane veered sharply to the left. To avoid taxi signs on the left side of the runway, the pilot rotated the aircraft. Shortly after rotation, an object struck the airplane.
Recovery and Landing
Once airborne, the pilot managed to move the seat forward, climb to pattern altitude, and land without further incident.
Maintenance and Findings
Prior to the flight, during the preflight inspection, the pilot observed a small amount of hydraulic oil pooled by the trim wheel. Maintenance personnel removed the left front pilot's seat to troubleshoot the issue and reinstalled it after the problem was resolved. After the flight, the pilot noticed that the left front seat had not been reinstalled in the seat rail; instead, it was resting on top of the rail.
Damage
Damage to the airplane consisted of a propeller strike, a hole in the undercarriage, and damage to both horizontal stabilizers.