History of Flight
On December 16, 2020, about 1417 mountain standard time, an experimental, amateur-built SilverLight LLC AR-1 gyroplane, registration N261MD, sustained substantial damage during an accident at Heber Valley Airport (HCR), Heber, Utah. The pilot received fatal injuries. The flight was conducted under Title 14 Code of Federal Regulations Part 91 as a personal flight.
Multiple witnesses observed the gyroplane take off from runway 22. One witness described the flight as “incredibly unstable” throughout its duration. Another witness reported seeing the gyroplane make an abrupt pull-up and right turn, with the mast parallel to the ground or beyond. Several witnesses noted the gyroplane entered a spin about its vertical axis before pitching nose-down and descending to the ground.
A witness video recording showed the gyroplane beginning its takeoff roll on runway 22. During the roll, the left landing gear and nose wheel lifted off and then settled back onto the runway. Shortly after liftoff, the gyroplane pitched nose-up and down multiple times, followed by an abrupt nose-up attitude and rapid altitude gain. About three seconds later, it banked right, then began to descend while rotating about the vertical axis. The gyroplane subsequently pitched nose-down and impacted terrain.
A security camera on airport property captured the gyroplane appearing in a very nose-high attitude, partially obscured by trees. It leveled in pitch while descending, then about two seconds later rolled right to more than 90°. Approximately two seconds after that, it pitched nose-down and struck the ground. Two additional security cameras recorded short segments of the flight.
Automatic dependent surveillance-broadcast (ADS-B) data showed the gyroplane taxiing onto runway 22 and initially tracking down the center. About 1,700 feet from the runway start, it was off the left side. About 2,200 feet from the start, it turned right about 45°, followed by a left turn of about 20°. The last ADS-B point, recorded at 1416:10, placed the gyroplane about 427 feet northeast of the accident site.
The gyroplane came to rest in a concrete-reinforced ditch on the north side of a highway bordering the airport. The first probable impact point was a gouge in the ground at the gyroplane's location. Three near-parallel ground scars about 15 feet from the main wreckage were consistent with rotor system ground contact before the first impact. A wire fence along the south side of the ditch had been pulled into the ditch by the fuselage.
Personnel Information
According to the pilot’s son, his father previously owned a side-by-side gyroplane for about two years before selling it. The son purchased his own side-by-side gyroplane, and the father flew with him for about a year before acquiring the AR-1. The son stated he never observed his father fly with the dramatic pitch-up and hard right attitude seen in the accident video. Medical records obtained during the investigation recorded the pilot’s weight at 143 pounds.
Aircraft Information
The manager of SilverLight Aviation LLC reported that the pilot approached him in June 2019 about building an AR-1 gyroplane. The owner chose a Rotax 915iS engine for better performance at the high-altitude airport (HCR). After completion, the manager flew the gyroplane for six hours, and an employee (a pilot and mechanic) flew it for about two hours. The owner then shipped the gyroplane to HCR. The manager stated the employee traveled to Utah to assist with reassembly and demonstrate operation with two people. The manager noted that the pilot was not a certified flight instructor but a very experienced pilot.
The employee visited the pilot for two days to set up the gyroplane and familiarize the owner with systems. The first day involved practice using the prerotator and charging forward without flight. The second day included multiple flights starting around noon. The employee reported that the owner exhibited flight performance issues including repeated excessive throttle, over-controlling, pilot-induced oscillations, and abrupt or aggressive control inputs. The employee stated he had to tell the owner to “reduce power” on every takeoff. Afterward, the employee reported to his employer that while the owner showed improvement, he still needed additional instruction and transition time. The employee offered additional training, but the owner declined.
Wreckage and Impact Information
Examination revealed substantial damage to the front of the fuselage, including the pilot’s station, consistent with a nose-down impact. The left vertical stabilizer was substantially damaged with a large section of the upper trailing edge separated, consistent with rotor contact. The center vertical stabilizer exhibited substantial damage with cracking and separation of composite material along the leading edge; its top showed material loss and paint transfer from rotor contact. The rudder separated from the center vertical stabilizer and was found near the wreckage, with substantial damage and multiple cracks on the starboard side and minor cracks on the port side.
The four-blade composite propeller had all blades separated at progressive distances from the hub; all four were recovered with minor tip damage and no evidence of tip contact with vegetation or soil. The propeller damage was consistent with rotor system contact. The rotor system remained attached to the mast, but the mast fractured above the fuselage. Both rotor blades showed upward, chord-wise bending near their roots and aft, counter-rotation bending. Red color transfer on one blade matched the empennage’s red color. Examination revealed no mechanical malfunctions or failures that would have precluded normal operation.
Engine performance data recovered from the engine control unit (ECU) included event log number 314, lasting 5 minutes 22 seconds. Data showed that at ECU time 47:46, linear throttle position increased to 100% and engine speed rose to about 5,800 RPM, remaining at those values for the remainder of the recorded data.
Additional Information
The AR-1 Pilot’s Operating Handbook stated: The manual is not a substitute for competent training; failure to adhere or take proper instruction can have fatal consequences. Minimum pilot weight is 144 pounds in the front seat. Maximum power at minimum takeoff weight can cause an abrupt climb rate that, if not corrected, may lead to climb angles beyond the placarded maximum. Approximately 80% of maximum takeoff power is considered comfortable for a minimum weight takeoff. A warning stated that any maneuver resulting in a low-G (near weightless) condition can cause catastrophic loss of lateral roll control with rapid main rotor RPM decrease; adequate rotor load should always be maintained, and aggressive forward control input from level flight or following a pull-up should be avoided.