Accident Overview
On July 22, 2022, about 0920 central daylight time, a Robinson R44 helicopter, registration N442JE, sustained substantial damage in an accident near Waterloo, Illinois. The helicopter was operated under Title 14 Code of Federal Regulations Part 137 as an aerial application flight. The pilot was not injured.
Pilot Report
The pilot reported that during a descent to apply fungicide to a corn field, the collective flight control stiffened to the point that he was unable to arrest the helicopter’s descent rate. Attempts to use cyclic control to flare and arrest the descent were unsuccessful, as the cyclic was not responsive. The helicopter’s skids contacted the ground, resulting in a rollover and cartwheel as the main rotors impacted the ground. The helicopter sustained substantial damage to the tail boom, fuselage, and main rotor system. The pilot stated that he suspected the flight controls’ hydraulic assist system had malfunctioned.
Examination Findings
During an on-site inspection, no obvious anomalies were found with the flight control system. The collective, cyclic, and anti-torque pedals were all connected and appeared normal. Flight control continuity was confirmed from the cockpit to the main rotor swashplate linkages and main rotor blades. Continuity was also confirmed from the cockpit anti-torque pedals to the tail rotor gearbox and tail rotor linkages. The hydraulic components were removed for detailed examination. All three servos (two forward and one aft) passed bench functionality tests. The hydraulic pump, reservoir, and fluids were normal. The forward right servo had a slightly bent piston shaft but remained fully functional. The spool drives of the forward and aft servos exhibited signatures consistent with normal operations. No anomalies were found that would preclude normal operation.