On August 23, 2014, about 1015 central daylight time, a Cessna 177 airplane, N3202T, impacted trees during landing rollout at Cedar Mills Airport (3T0), Gordonville, Texas. The pilot and front seat passenger were seriously injured and the two rear seat passengers received minor injuries. The airplane sustained substantial damage. The airplane was registered to and operated by a private individual under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Day visual meteorological conditions prevailed at the time of the accident and no flight plan was filed. The flight originated from Lakeview Airport (30F), Lake Dallas, Texas about 0945. The pilot stated that during a visual approach to Runway 25 at 3T0 he utilized left aileron and right rudder control inputs, based on a crosswind from the south. As the airplane descended below a tree line, the wind decreased and the airplane drifted to the left. During touchdown and rollout on the turf runway, the airplane continued to drift to the left. The pilot attempted to input right rudder, but felt like his input was not having any effect. The airplane subsequently departed the left side of the runway and impacted multiple trees. Examination of the airplane revealed extensive damage to both wings and the fuselage. After the accident, the pilot stated that the lack of rudder effect may have been due to the front seat passenger's foot blocking a rudder pedal. At 1015 the weather observation station at North Texas Regional Airport (GYI), Denison, Texas, located about 10 miles southeast of the accident site, reported the following conditions: wind 200 degrees at 11 knots, visibility 10 miles, clear skies, temperature 31 degrees Celsius (C), dew point 17 degrees C, altimeter setting 30.02 inches of mercury. Examination of the airplane revealed normal flight control continuity. The pilot seat was found fully engaged on the rails and locked in position. No secondary seat stop was observed. The front passenger seat was displaced to the left and separated from the rails. The aft bench was secured to the floor. All seat restraint belts were still attached to the corresponding structure and no torn stitches were observed. There airplane was not equipped with shoulder harnesses. Examination of the airframe and engine revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation.