Incident Summary
A pilot reported that during the takeoff roll, he did not inform the rear seat passenger about the presence of brake pedals under the seat. As the aircraft accelerated, the pilot noted that the airplane pitched to the left more severely than ever before. Instead of aborting the takeoff, he applied right rudder and right brake to correct the path. The airplane returned to the center of the runway, but when the pilot released the right brake while continuing to apply power, the aircraft pitched hard left toward a group of small trees.
To avoid a head-on collision with a tree, the pilot applied hard left rudder as the aircraft began to ground loop. The right side of the aircraft subsequently struck a tree, bringing the airplane to a stop.
Post-Crash Examination
A post-crash inspection of the left wheel and brake assembly revealed no mechanical malfunctions or anomalies.
Pilot's Statement
The pilot stated his belief that the rear seat passenger may have inadvertently rested a foot against the left brake pedal without realizing it.