Incident Sequence
During the landing flare, the pilot reported flaring late, which caused the aircraft to bounce and porpoise. The pilot then made a comment that was misinterpreted by a pilot-rated passenger occupying the right seat. The passenger understood the comment as a request for assistance and began manipulating the controls. With two people applying conflicting control inputs, a loss of control occurred.
Runway Excursion and Damage
As a result of the loss of control, the aircraft departed the runway. The wing tip struck a yucca plant, causing the aircraft to spin around. The main landing gear subsequently failed. The aircraft slid to a stop, partially on the runway.