NTSB Identification: ANC02FA108.
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Accident occurred Wednesday, August 28, 2002 in Ketchikan, AK
Probable Cause Approval Date: 11/25/2003
Aircraft: Robinson R-44, registration: N7189T
Injuries: 2 Fatal.
NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.
The owner/pilot and the sole passenger departed in the helicopter for a night cross country flight en route to a remote cabin on a lakeshore. When they did not return the next day, a search was initiated. The helicopter was discovered floating inverted in the lake near the remote cabin. The pilot's handheld GPS was found floating on the surface of the lake, and data from the accident flight was extracted from its memory. The GPS recorded date, time, position, groundspeed, heading, and altitude information. According to the GPS, the flight departed at 1940, about 9 minutes before official sunset, and followed a course along several coastal canals, and then headed inland to the lake where the accident occurred. The lake has a surface elevation of about 390 feet msl. The helicopter climbed to an altitude of 1,268 feet msl to clear terrain prior to reaching the lake, and once clear of terrain, the helicopter descended toward the lake. The GPS ground track indicates the helicopter followed the north shore of the lake to the area where the destination cabin was located, and descended to about 35 feet above lake level in the vicinity of the public use cabin. The helicopter maneuvered there for several minutes, and then reversed course. After the course reversal, the helicopter's ground speed and altitude began to increase, until the helicopter reached about 170 feet above lake level, and the helicopter's ground speed had decreased to about 15 mph. Seventeen seconds later, at 2025, the track ended, following a steep and rapid descent. The termination of the flight track was at an elevation consistent with the level of the lake. The accident site was situated in an area surrounded by hills and mountain ridges, and classified as a rainforest, which was receiving higher than normal amounts of rainfall. Area weather forecasts, before and after the accident, reflected scattered to broken cloud layers as low as 1,000 to 1,500 feet agl with mountaintops and ridges occasionally obscured by clouds, and overcast cloud layers as low as 2,500 feet agl. Visibility was generally greater than 3 miles with reports of marginal VFR and rain showers in some areas. An FAA inspector who was in the general vicinity when the helicopter departed for the cabin said the night was very dark due to low clouds and precipitation. The pilot held a commercial pilot certificate with a rotorcraft rating. He also held a flight instructor certificate for rotorcraft. According to FAA records, the pilot had accumulated about 838 total flying hours, of which 791 were in rotorcraft. The pilot was not instrument rated. An inspection of the helicopter did not reveal evidence of any preimpact mechanical anomalies.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: The pilot's failure to maintain control of the helicopter in-flight due to spatial disorientation, which resulted in an uncontrolled descent and impact with the surface of a lake. Factors contributing to the accident were the high terrain surrounding the lake, and the lack of visual cues due to the dark night and low clouds. Full narrative available
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