NTSB Factual Report

On April 3, 2001, about 1745 Alaska daylight time, a wheel-equipped Cessna 207 airplane, N1581U, sustained substantial damage after colliding with terrain, about eight miles north of Nightmute, Alaska. The airplane was being operated as a visual flight rules (VFR) scheduled domestic passenger flight under Title 14, CFR Part 135, when the accident occurred. The airplane was operated as Flight 262 by Grant Aviation Inc., Anchorage, Alaska. The commercial certificated pilot and one passenger received serious injuries, two passengers received minor injuries, and three passengers were not injured. Visual meteorological conditions prevailed in the area of the accident, and VFR company flight following procedures were in effect. The accident flight originated at the Nightmute Airport, about 1730. The intended routing of Flight 262 was from Bethel, Alaska, to Toksook Bay, Alaska, to Nightmute, to Newtok, Alaska, and then a return to Bethel.

During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), on April 3rd, the director of operations for the operator reported that the flight had crashed, and search and rescue operations were underway. On April 6, 2001, the NTSB IIC interviewed the pilot who stated that while he was en route to Toksook Bay, he contacted the village agent via radio. The weather conditions were reported by the agent as 800 feet overcast, visibility 5 miles, with a light wind from the southeast. Before departing Nightmute, the pilot said he set the airplane's altimeter to the field elevation (15 feet msl). After departure, he proceeded toward Newtok, but skirted an area of low hills by flying toward the east before turning toward Newtok. He said he was flying about 450 feet above the ground. About 10 minutes after departure, the pilot said the horizon began to become obscured and the area ahead of the airplane turned white. He said there was no precipitation, rather the ground and sky became indistinguishable. He began a right turn toward the east, but about 2 seconds after beginning the turn, the airplane suddenly collided with snow-covered terrain.

In the Pilot/Operator report (NTSB Form 6120.1/2), the director of operations reported the weather conditions at the accident site as an estimated indefinite ceiling of 500 to 600 feet agl, and the visibility was estimated as two miles in haze/whiteout with no precipitation.

On September 13, 2001, in a telephone conversation with the NTSB IIC, the right front seat passenger reported that as the flight progressed toward Newtok, the visibility was about one mile under gray sky conditions. Just prior the accident, the visibility began to decrease, and the airplane then collided with the snow. The passenger did not report any precipitation.

The airplane came to rest on its right side. The engine and propeller were torn off the airframe. The pilot provided emergency care for the passengers, and contacted an over-flying jet airplane on a hand-held radio. Emergency personnel arrived by helicopter about 2 hours later.

The airplane was equipped with an avionics package provided by the Federal Aviation Administration's Capstone Program. The Capstone Program is a joint industry/FAA demonstration program that features, among others, global positioning system (GPS) avionics, weather and traffic information provided through automatic dependent surveillance-broadcast (ADS-B), traffic information service-broadcast (TIS-B) equipment, and terrain information depicted on a multifunction display (MFD) installed in the cockpit. The Capstone program provides radar-like services to participating air carrier aircraft operating in a non-radar environment of Western Alaska. At the time of the accident, position information from Capstone equipped airplanes, to the Anchorage Air Route Traffic Control Center (ARTCC), Anchorage, Alaska, is provided by the ADS-B equipment in the airplane, and requires ground based radio repeater sites to facilitate the transmittal of position data. The area of the accident was not within radio coverage of a currently established repeater site.

Terrain depiction information, based on GPS data, is one of several visual display options available to the pilot. Other options include custom maps, VFR sectional charts with topographical features, IFR charts, flight plan and traffic information, and weather data. The airplane's position can be displayed in relation to its location over the terrain, and may include bearing and distance information to selected points. Selection of the terrain mode for display, provides the pilot with color shading, depicting areas of terrain that are black (2,000 feet below the aircraft), green (between 2,000 and 700 feet below the aircraft), yellow (between 700 and 300 feet below the aircraft), and red (at or within 300 feet of the aircraft). Accurate depiction of terrain (in the terrain mode) requires the pilot to manually set a barometric pressure setting in the multifunction display menu. The Capstone avionics equipment does not automatically receive barometric pressure data from the aircraft's altimeter. Selection of the map mode does not provide any terrain warning/awareness information.

During the interview with the NTSB IIC, the pilot said that he received training in the use of the Capstone equipment from the University of Alaska, Anchorage, and from his company. He also said that during the accident flight, he selected the moving map display with a five mile scale. He did not observe any warning flags illuminated on the multifunction display. He did not manually enter any barometric pressure data into the Capstone equipment. The pilot said that he routinely utilized his own personal GPS receiver that has a color moving map display. He said he is more familiar with his own GPS, and had it installed on the top of the instrument panel glare shield. He said that since the terrain in Western Alaska is usually quite flat, he routinely utilized the Capstone map mode with the GPS "go to" function for each leg/destination of a route, not the terrain mode.

The closest official weather observation station to the accident site is Hooper Bay, Alaska, which is located 71 nautical miles northwest of the accident site. On April 3, at 1835, an Aviation Routine Weather Report (METAR) was reporting in part: Wind, 140 degrees (true) at 9 knots; visibility, 9 statute miles; clouds and sky condition, 800 feet broken, 1,200 feet broken, 3,100 feet overcast; temperature, 32 degrees F; dew point, 28 degrees F; altimeter, 28.92 inHg.

On April 3, at 1753, a METAR from Bethel, located 81 nautical miles east of the accident site, was reporting in part: Wind, 160 degrees (true) at 18 knots, gust to 24 knots; visibility, 10 statute miles; clouds and sky condition, 1,900 feet broken, 2,600 feet overcast; temperature, 35 degrees F; dew point, 32 degrees F; altimeter, 28.94 inHg.

NTSB Probable Cause

The pilot's continued VFR flight into instrument meteorological conditions, and his failure to maintain adequate distance/altitude from terrain, resulting in a collision with terrain while maneuvering. Factors in the accident were flat light conditions, snow-covered terrain, and the pilot's failure to utilize on-board Capstone flight/navigation instruments to display terrain awareness data.