What happened
The incident occurred following takeoff from an unestablished off-airport landing zone. Shortly after becoming airborne, the helicopter encountered heavy rain showers that significantly degraded visibility conditions. The pilot attempted to return to the previously used landing zone; however, the reduced visibility prevented visual reference with the ground.
During this maneuver, the tail rotor of the helicopter contacted a lake situated adjacent to the intended landing area. Following the impact, the aircraft reportedly sank into the water.
Findings
The primary factors contributing to the accident were the heavy rain showers encountered shortly after takeoff and the resulting loss of visual reference with the ground. These conditions prevented the pilot from maintaining situational awareness necessary to avoid terrain and water obstacles during the return attempt.