Amateur-built VORTEX accident near Lakeport, California, December 2, 2021

The NTSB's narrative final · quoted from the NTSB record

A witness reported seeing the gyroplane flying straight and level about two miles from the departure airport. The witness reported the gyroplane then tumbled tail over nose three times before he lost sight of it below the tree line. The gyroplane sustained substantial damage when it impacted the heavily vegetated terrain. The smell of fuel was present at the accident site and there was no evidence of a wire or bird strike. Additionally, there were no reports of downed power lines or power outages in the accident area. Examination of the gyroplane revealed no evidence of any preaccident mechanical malfunctions or failures that would have precluded normal operation. The gyroplane was equipped with a horizontal stabilizer that remained intact. The engine was likely producing power at the time of the accident, because two of its propeller blades contacted the main rotor blades during the accident sequence. The main rotor blades sustained minimal damage, consistent with the gyroplane entering a low-rotor-rpm state for undetermined reasons before ground impact. According to the Federal Aviation Administration (FAA), FAA-H-8083-21, Chapter 21, Gyroplane Emergencies, if rotor force is rapidly removed, some gyroplanes may pitch forward abruptly into a power pushover event and if not corrected can continue to tumble and become irreversible.

The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.