NTSB Factual Report

On September 17, 2010, about 0023 central daylight time, a Robinson R44 II helicopter, N145DM, piloted by a commercial pilot, was destroyed during an in-flight collision with the waters of Island Lake near Duluth, Minnesota. The flight was being conducted under 14 Code of Federal Regulations Part 91 without a flight plan. Night visual meteorological conditions prevailed. The pilot sustained minor injuries. The flight departed from a beach on Island Lake and was on the initial climbout at the time of the accident. The intended destination was Duluth International Airport (DLH), Duluth, Minnesota, which was located about 10 miles south of the accident site.

The pilot reported that he had flown from DLH to the beach site on Island Lake in order to show the helicopter to some prospective clients. After spending several hours, he decided to return to DLH. The pilot stated that he lifted off into a hover, and subsequently established a 600 foot-per-minute rate of climb at 60 knots airspeed to depart the area. As he climbed out, he reported a "sinking feeling in the seat all of a sudden," and noticed that the vertical speed indicator "started to dip down indicating a descent." His flight instruments indicated that the helicopter was at 60 knots airspeed and in level flight; "everything checked out." He increased engine power, but was still descending. The pilot referenced the flight instruments a second time and noted that "all indications showed level and 60 [knots]." He recalled thinking that the helicopter might have encountered a "microburst of some type." He added that he could not tell the helicopter's exact height above the water because of the night lighting conditions. The helicopter hit the water at about 60 knots. The pilot commented that he thought the helicopter was still higher off the water and, as a result, did not flare prior to impact.

A witness reported that the start and warm up were unremarkable. In addition, the liftoff and initial climb also appeared normal. He stated, "If the entire event took 10 seconds, only the last 2, showed concern as we could see the distance between the [helicopter's navigation] lights and the reflection in the water markedly become closer, ultimately converging." He noted that the helicopter appeared to be level and remain in controlled flight the entire time.

A post accident examination of the helicopter did not reveal any anomalies consistent with a pre impact failure or malfunction.

Weather conditions recorded at DLH, located about 10 miles south of the accident site, at 2355, included: Scattered clouds at 11,000 feet above ground level (agl), 10 miles visibility, and winds from 180 degrees at 4 knots. At 0055, conditions included: Broken clouds at 10,000 feet agl, 10 miles visibility, and wind from 240 degrees at 7 knots. The moon set at 0058, about 35 minutes after the accident. It was in a waxing gibbous phase, with 73 percent of the visible disk illuminated.

The witness commented that the "night was dark, but there was a distinguishable horizon." He did not feel that the conditions were "adverse" for the pilot's return flight.

The pilot informed Federal Aviation Administration (FAA) inspectors that he had executed a similar type of night departure in June; although, the night of the accident was darker. The pilot did not hold an instrument rating. However, he was reportedly working toward the rating and he had accumulated about 30 hours of instrument flight time.

NTSB Probable Cause

The pilot's failure to identify and arrest the helicopter's descent due to spatial disorientation.