Before the flight in the experimental Thorp T-18, the pilot unbolted and rebolted the pilot’s seat from its middle position to the forward position.
He did not check to see if the flight control stick movement would be restricted in this new configuration.
During the takeoff roll, the plane would not rotate when he moved the flight control stick aft.
Not realizing the seat prevented the flight control stick movement to the full aft position, he adjusted the elevator trim and the plane subsequently lifted off, however, it would not climb.
He then aborted the takeoff, however the airplane did not have sufficient distance to stop. It departed the runway at San Rafael, California, and traversed through a field, hit trees, and came to rest inverted.
The airplane sustained substantial damage to the wings, rudder, and vertical stabilator.
The NTSB determined the probable cause as the pilot’s delayed decision to abort the takeoff. Contributing to the accident are an inadequate modification to the seat position, and the pilot’s failure to check flight controls for freedom and correct movement.
NTSB Identification: WPR15CA066
This December 2014 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.