What happened
On 24 March 2017, a Hughes 500 Model 369E, registration G-MRRR, was completing a private flight from the Cotswolds to a landing site near Reading, Berkshire. As the aircraft approached the destination, the pilot observed bystanders on a river bank and altered the approach path to fly over fields toward the north-west corner of the site.
During the approach, the aircraft entered the landing area and experienced a loss of translational lift. In an attempt to compensate, the pilot increased power by raising the collective while simultaneously applying left pedal input. This maneuver resulted in the helicopter entering a clockwise descending spin. Despite the pilot closing the throttle, the aircraft continued to rotate several times before striking the ground with significant force. The impact caused the right-hand skid to collapse, leading the helicopter to roll onto its side. The impact caused serious damage to the main and tail rotor systems. Both the pilot and the single passenger were uninjured and were able to exit the aircraft without assistance.
The investigation
The investigation examined the flight history and the physical condition of the aircraft following the incident. Technical analysis of the Hughes 500 Model 369E revealed no evidence of any mechanical malfunction occurring prior to the accident. The damage sustained by the airframe and rotor systems was found to be consistent with the right skid collapsing and the subsequent rollover.
Findings
- The loss of translational lift occurred as the helicopter slowed for landing.
- The pilot applied excessive power to counter the loss of lift without sufficient left pedal input, which initiated the uncontrolled clockwise rotation.
- A 20-knot wind from 050° contributed to the difficulty of maintaining control during the maneuver.