N18BT

The pilot reported that he was landing the tail wheel airplane when the accident happened. He stated that the airplane touched down on one main wheel first and the airplane shifted and rapidly turned right. He stated that the airplane's movement resulted in his passenger's body shifting to the left against the left rudder/brake pedal. The rear seat rudder pedals are located near the front seat occupant's hips. The pilot stated that he attempted to correct with left rudder, but was unable due to the obstruction of the rudder pedal by the front seat passenger's body. The airplane subsequently ground looped. The damage to the airplane included collapse of the main landing gear, damage to the left lower wing, and damage to the upper wing.