SEA03LA118 · Herrin Hornet

A witness to the accident reported that the pilot of the accident airplane made numerous high-speed taxi runs prior to the accident flight. After completing the taxi maneuvers, the pilot told the witness he was apprehensive about trying to fly the airplane on account of localized gusty winds. After talking to the witness, the pilot taxied back to the runway and resumed the taxi tests. The witness reported that after completing a number of passes down the runway, he observed the airplane takeoff. He reported that the airplane appeared to be porpoising as it ascended over the runway. Additional witnesses reported that they observed the airplane in a climbing right turn over the airport. The airplane climbed to about 200-300 above ground level (AGL) and appeared to be in a modified downwind for runway 25. The witnesses reported that as the pilot turned from right base to final, the airplane abruptly pitched nose down (approximately 60 degrees). The witnesses reported that the airplane momentarily returned to a level flight attitude, but pitched down a second time just before impacting terrain in a nose low attitude. Maintenance records indicated that the airplane was issued a special airworthiness certificate, experimental category, on April 23, 2003. The accident flight was the airplanes first flight subsequent to receiving the airworthiness certificate. Post accident examination of the aircraft revealed no evidence of a mechanical failure or malfunction.

Verbatim NTSB analysis and probable cause from the NTSB dataset