On December 4, 2022, a Rotorsport UK Ltd Cavalon gyroplane, registration N401GR, was involved in a fatal accident near Beverly, Massachusetts. The aircraft was being operated as a personal flight under 14 CFR Part 91. The pilot, who was also the owner, had approximately 120 total flight hours, all of which were in this specific aircraft. The gyroplane had recently returned to service following a three-month maintenance period, during which the pilot had not flown.
What happened
At approximately 11:35 EST, the pilot taxied from his hangar to runway 34 and received takeoff clearance from the tower controller. Security footage of the event showed that during the initial climb, the aircraft leveled off briefly at approximately 40 feet above ground level before resuming a shallow climb accompanied by a left yaw. As the climb continued, the aircraft tilted to the right and entered a rapid right roll. The gyroplane completed a full 360-degree roll to the right and descended out of control, impacting the right side of the paved runway before skidding into the grass.
The pilot sustained 1 fatal injury. The aircraft sustained substantial damage, including the separation of the rotor head from the mast due to impact forces. The engine remained intact and continued to operate at nearly full power for approximately two minutes following the impact.
The investigation
Data retrieved from two electronic flight displays showed that during the takeoff roll, all engine parameters—including RPM, oil pressure, fuel flow, and temperature—were normal. As the aircraft lifted off at 53 knots, it maintained a vertical speed of 371 feet per minute. While climbing through 150 feet MSL, the aircraft experienced a hard left yaw. Within three seconds, the vertical speed increased to 2,692 feet per minute as the aircraft rolled and descended.
Mechanical examination of the N401GR revealed no evidence of engine or airframe anomalies that would have prevented normal operation. Control continuity for both pitch and roll was confirmed from the cockpit to the rotor head. The rudder trim was found in a 30-degree right position (indicating left rudder deflection) but was undamaged.
Toxicological analysis of the pilot's blood revealed the presence of Delta-9-THC and 11-hydroxy-delta-9-THC. An autopsy also noted an enlarged heart and atherosclerosis, though investigators found no evidence that a sudden medical event caused the accident.
Findings
- The pilot's improper yaw control during the initial climb led to an excessive sideslip.
- The excessive sideslip caused a loss of aircraft control.
- The aircraft manufacturer has previously noted that extreme sideslip in a gyroplane can cause the rotor disc to pitch down, leading to a rapid roll toward the direction of flight.
- The pilot had not flown for approximately three months prior to the accident.