47G SUPER C 4 N865Z accident near Timmonsville, South Carolina

Probable cause

The pilot's decision to maneuver the helicopter at a low altitude near trees, which resulted in collision with the trees.

NTSB analysis

On the afternoon of the accident, the pilot was scheduled to participate in a fundraising event in which he would drop golf balls from his helicopter. The pilot departed his home airport and flew to a private uncharted airfield with a turf runway, which was about halfway between the departure airport and the fundraising event location but not directly between the departure and destination locations. Radar data for the flight ended when the helicopter was about 800 ft north of the accident site and proceeding along a northwest track away from the accident site. The amount of flight time and the track after the radar data ended could not be determined. A witness reported hearing the engine as the helicopter approached the area; the engine noise continued until he heard the sounds of rotor blades striking trees and a subsequent explosion. The helicopter struck a 60-ft-tall tree at the edge of a tree line surrounding a 2-acre residential lawn, which was located near the runway extended centerline and about 300 ft from the approach end of the runway. The debris path was oriented on a heading of 325°, and the runway was oriented on a heading of about 330°. The runway had not recently been maintained or used, as indicated by the 4-ft-tall grass on the entire runway.

Given the available evidence, the investigation could not determine why the pilot flew to the private uncharted airfield. The pilot's destination was about 13 miles northwest of the accident site, and it is unknown if or where he intended to stop along the way. No golf ball remnants were found at the accident scene, and there was no indication if the pilot planned to pick up the golf balls along the way to or at the destination.

The tall grass on the runway made the runway itself an unlikely planned landing location. The pilot was not likely performing a forced landing to the runway (or the residential lawn) because after arriving in the area, he initially flew away from the runway and lawn for an unknown amount of time before apparently lining up with the runway prior to impact. The witness information indicated that the engine was operating, and the fragmentation of the main rotor blades showed that the rotor system was rotating. Also, examination of the airframe and engine revealed no preimpact mechanical malfunctions that would have precluded normal operation.

Although postaccident toxicological testing detected tetrahydrocannabinol (THC) in the pilot's cavity blood, the blood concentration level at the time of the accident could not be reliably determined due to postmortem redistribution, during which THC levels may rise or fall. Thus, the toxicology results were inconclusive regarding when the pilot's marijuana use occurred and whether it would have had performance-impairing effects during the accident flight.

Text from the NTSB. Open the NTSB docket for ERA17FA164 for the full record.