Incident Overview
A helicopter was supporting local authorities in a search operation related to a boating incident on a lake. The aircraft crashed into the water after encountering a loss of tail rotor effectiveness (LTE) during a hover. The helicopter came to rest on its left side after impact.
Flight Details
The pilot and a passenger/observer were conducting the mission. The helicopter was flown 20–30 feet above the water on a north-south pass parallel to the shoreline. After the observer sighted something in the water, the pilot turned the helicopter left through a 180-degree turn, flew over the lake, and then inbound near the shoreline. While hovering out of ground effect in a west-southwest direction, the helicopter experienced a loss of tail rotor effectiveness and began a spin to the right. The pilot was unable to stop the spin, and the helicopter impacted the water.
Weather conditions at the time, as reported by a nearby observation facility, included wind from 130 degrees at 9 knots.
Examination Findings
Post-accident examination of the helicopter revealed damage consistent with a sudden stoppage of the main rotor system and tail rotor driveshaft upon impact with the water and terrain. Metallurgical examination showed that both the main rotor driveshaft and the tail rotor driveshaft fractured in torsional overload. Aside from the impact damage, no discrepancies or anomalies were found that would have prevented normal operation of the helicopter before the crash.