Lakeport, CA, USA
N425RD
RUSSELL W DYER VORTEX
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.
HISTORY OF FLIGHT On December 2, 2021, about 1115 Pacific standard time, an experimental amateur-built, Sport Copter Vortex gyroplane, N425RD, was substantially damaged when it was involved in an accident near Lakeport, California. The pilot was fatally injured. The gyroplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. Witnesses located about 2 miles west of the accident site observed the gyroplane in level flight, about the same height as a set of telephone poles, and then saw it tumble tail over nose three times before they lost sight of it behind a tree line. The gyroplane was not equipped with an automatic dependent surveillance – broadcast transponder and it was flying too low for radar coverage. PILOT INFORMATION The pilot had been involved in another accident in the same area while flying a gyroplane in August 2020. The National Transportation Safety Board (NTSB) determined the probable cause of that accident to be: “The pilot’s distraction and failure to maintain adequate airspeed during a low altitude maneuver, which resulted in a loss of aircraft control and collision with terrain.” See NTSB accident report WPR20CA253. Flight logbook records were not recovered for the pilot; however, at the time of the last accident, he reported to the NTSB that he had accrued 853.8 total hours of flight time in single-engine airplanes and 71.3 total hours in rotorcraft. WRECKAGE AND IMPACT INFORMATION The entire gyroplane came to rest generally intact on its left side on flat open terrain covered with tall heavily vegetated brush near the shoreline of a lake. The fuselage sustained crush and bending damage, consistent with the impact, and there was no evidence to indicate an inflight structural failure. The smell of fuel was present at the accident site and there was no evidence of a wire or bird strike. There were no reports of damaged power lines or power outages in the accident area. The rotor head and mast were intact and remained attached to the airframe. The main rotor blade hub could be rotated freely. The main rotor blades remained attached to the hub bar and straps and both showed a 20° downward bow outboard of the strap fittings. Both blades exhibited similar tear marks to their trailing edge skins, just outboard of the straps. One blade exhibited a black streak on its lower surface next to the strap consistent with engine propeller blade contact. Flight control continuity was established from the foot pedals through to the rudder surface, and from the cyclic control stick through to the rotor mast. There was no evidence of a catastrophic engine failure, and the engine crankshaft could be rotated via the propeller reduction drive hub. One propeller blade remained attached at the hub. The second propeller blade had detached at the root, and the third propeller blade had similarly detached but its tip was not located in the surrounding heavy vegetation. Further examination of the gyroplane revealed no evidence of any preaccident mechanical malfunctions or failures that would have precluded normal operation. MEDICAL AND PATHOLOGICAL INFORMATION An autopsy of the pilot was performed by Bennet Omalu Pathology, Stockton, California. The autopsy report was reviewed by the NTSB Investigator-In-Charge. According to the autopsy report, the cause of death was blunt force trauma. Toxicology testing performed at the FAA Forensic Sciences Laboratory found no drugs of abuse. ADDITIONAL INFORMATION According to the FAA Rotorcraft Flying Handbook (FAA-H-8083-21), Chapter 21, Gyroplane Emergencies, if the rotor force is rapidly removed, some gyroplanes may tend to pitch forward abruptly, often referred to as a power pushover, forward tumble, or buntover. “A power pushover can occur on some gyroplanes that have the propeller thrust line above the center of gravity and do not have an adequate horizontal stabilizer.” Removing the rotor force is often referred to as unloading the rotor and can occur if pilot-induced oscillations become excessive, in extremely turbulent conditions are encountered, or the nose of the gyroplane is pushed forward rapidly after a steep climb. If a correction is not made, the nose pitching action can become “self-sustaining and irreversible.” Additionally, the FAA handbook states that “an adequate horizontal stabilizer slows the pitching rate and allows time for recovery.” According to the Pilot’s Operating Handbook, Section 3.10, Emergency Procedures, Flight Control Malfunction: “an immediate reduction of power, respectively speed [sic] may be necessary to avoid pitch oscillations or other effects affecting dynamic or static stability.”
The pilot’s loss of control for reasons that could not be determined and the delayed remedial action to recover from the power pushover event.
Source: NTSB Aviation Accident Database
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