On September 10, 1993, at 1530 mountain daylight time, an Aerospatiale SA365N2, N818R, collided with the water in the Great Salt Lake while maneuvering 10 miles west of Ogden, Utah. Visual meteorological conditions prevailed at the time and no flight plan was filed for the corporate flight. The helicopter was destroyed and the certificated Airline Transport pilot and two passengers suffered minor injuries, two passengers were seriously injured, and one passenger was fatally injured. The flight had departed from the Ogden area on September 19, 1993, at 1330. The pilot reported that the purpose of the flight was to take a camera crew up to produce aerial videography and still photos of the area's mineral extraction facilities. The helicopter had been flying in the area for approximately two hours at varying altitudes from 50 feet to 900 feet. While travelling back to the landing area, the camera director wanted to get one more shot of the water at low level. The pilot noted that the water was calm and glassy and provided no depth perception. The pilot set the decision height "bug" to 50 feet on the radar altimeter then began the descending right turn at 300 feet per minute and 95 knots. At 50 feet above water level, the pilot rolled to level flight and slowed the helicopter to 60 to 70 knots. The pilot was using outside reference while maneuvering and stated that he suddenly turned his attention to the radar altimeter when he felt the sensation of speed over the water and noted that the altitude read 10 feet. Approximately two seconds later the helicopter contacted the water surface. The helicopter pitched over and came to rest on its left side in four feet of water. The pilot reported that there were no mechanical failures or malfunctions with the helicopter at the time of the accident.