The owner/builder of the Rotorway 162F was performing pedal turns while conducting initial flight tests. During a turn the left pedal "popped" and "fell away." He immediately dropped the collective and landed hard, causing significant damage to the tail boom. He inspected the helicopter and discovered the foot pedal scissor beam had pulled away from its retaining bolt. The scissor beam was designed to be sandwiched between two nylon pivot bushings, and retained by an aluminum bushing and bolt. During the construction phase he inadvertently mounted the aluminum bushing on the inside of the scissor beam, allowing the beam to be pulled past the mounting bolt when pressure was applied.