# NTSB ANC08LA042: Cessna 180, N66036, White Mountain, AK, March 11, 2008 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: March 11, 2008, 10:50 local (18:50 UTC) - Place: White Mountain, AK - Coordinates: 64.709724, -162.762771 - Nearby events: https://openairdocs.org/map.md?lat=64.7097&lon=-162.7628&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute-cruise: Loss of visual reference](https://openairdocs.org/ntsb-events/402) - Highest injury: Minor injuries - Injuries: 2 minor, 1 uninjured - Status: Completed, report August 28, 2008 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - Parties: FAA-FAI-FSDO 01 - NTSB case key (mKey): 67647 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC08LA042 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/67647/pdf - Page: https://openairdocs.org/ntsb/ANC08LA042 ## Probable cause The pilot’s inadvertent flight into flat light/whiteout conditions over snow-covered terrain. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Terrain: mountainous/hilly terrain](https://openairdocs.org/ntsb-findings/03021010): Environmental issues › Physical environment · Not specified; cases with it: [Cessna 180K, 1 case](https://openairdocs.org/ntsb-findings/03021010/cases.md?model=2072624), [All aircraft, 329 cases](https://openairdocs.org/ntsb-findings/03021010/cases.md) - [Ceiling/visibility/precip: whiteout](https://openairdocs.org/ntsb-findings/03035060): Environmental issues › Conditions/weather/phenomena · Effect on operation (probable cause); cases with it: [Cessna 180K, 1 case](https://openairdocs.org/ntsb-findings/03035060/cases.md?model=2072624), [All aircraft, 13 cases](https://openairdocs.org/ntsb-findings/03035060/cases.md) - [Terrain: snowy/icy terrain](https://openairdocs.org/ntsb-findings/03021030): Environmental issues › Physical environment · Not specified; cases with it: [Cessna 180K, 1 case](https://openairdocs.org/ntsb-findings/03021030/cases.md?model=2072624), [All aircraft, 77 cases](https://openairdocs.org/ntsb-findings/03021030/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute-cruise: Loss of visual reference](https://openairdocs.org/ntsb-events/402) (defining event); cases with it: [Cessna 180K, 1 case](https://openairdocs.org/ntsb-events/402/sequence.md?model=2072624), [All aircraft, 242 cases](https://openairdocs.org/ntsb-events/402/sequence.md) - [Enroute-cruise: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Cessna 180K, 8 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=2072624), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The airline transport pilot was in cruise flight at 2,500 feet msl over snow-covered mountainous terrain. He said the weather conditions were reported as having a ceiling of about 3,000 feet, and a visibility of 10 miles. The route crossed an area of low hills, and the pilot said the visibility began to deteriorate. He descended to about 2,000 feet msl, and suddenly flew into whiteout conditions. The airplane collided with a mountain ridge and overturned. The airplane received structural damage to the wings, landing gear, and fuselage. A pilot who flew to the site shortly after the accident stated that he had difficulty seeing the ridge line. He stated that “visibility was good, about 5 miles, but I couldn’t make out the ridge. The ridge line was relatively horizontal, without any contrasting features, making it difficult to identify against the sky.” The Federal Aviation Administration’s Aeronautical Information Manual (AIM), Section 7-5-13, “Potential Flight Hazards, Flying in Flat Light and Whiteout Conditions,” notes that whiteout “occurs when a person becomes engulfed in a uniformly white glow…a result of being surrounded by blowing snow, dust, sand, mud or water.” The AIM states that flat light “is an optical illusion, also known as ‘sector or partial whiteout.’ Flat light conditions are usually accompanied by overcast skies inhibiting visual cues. Flat light can completely obscure features of the terrain, creating an inability to distinguish distances and closure rates.” According to the AIM, “flat light conditions can lead to a whiteout environment quite rapidly, and both atmospheric conditions are insidious; they sneak up on you as your visual references slowly begin to disappear.” ## Factual narrative On March 11, 2008, about 1050 Alaska daylight time, a wheel ski-equipped Cessna 180 airplane, N66036, sustained substantial damage when it collided with snow-covered terrain, about 16 miles east-northeast of White Mountain, Alaska. The airplane was being operated as a visual flight rules (VFR) cross-country personal flight under Title 14, CFR Part 91, when the accident occurred. The airplane was operated by the pilot who was volunteering his airplane in support of the annual Iditarod sled dog race in Alaska. The airline transport certificated pilot was not injured. The two passengers received minor injuries. The flight originated at the Koyuk Airport, Koyuk, Alaska, about 1020, en route to White Mountain, and no flight plan was filed. During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), on March 11, the pilot reported that he departed from Koyuk with several other airplanes, and the weather conditions were reported as having a ceiling of about 3,000 feet, and a visibility of 10 miles. As the flight progressed toward White Mountain, he was in cruise flight at 2,500 feet msl. The route crossed low hills east of the airport, and the pilot said the visibility began to deteriorate. He descended to about 2,000 feet msl, and suddenly flew into whiteout conditions. The airplane collided with a mountain ridge about 2,000 feet msl and overturned. The airplane received structural damage to the wings, landing gear, and fuselage. A pilot who flew to the site shortly after the accident stated that he had difficulty seeing the ridge line. He stated that “visibility was good, about 5 miles, but I couldn’t make out the ridge. The ridge line was relatively horizontal, without any contrasting features, making it difficult to identify against the sky.” The Federal Aviation Administration’s Aeronautical Information Manual (AIM), Section 7-5-13, “Potential Flight Hazards, Flying in Flat Light and Whiteout Conditions,” notes that whiteout “occurs when a person becomes engulfed in a uniformly white glow…a result of being surrounded by blowing snow, dust, sand, mud or water.” The AIM states that flat light “is an optical illusion, also known as ‘sector or partial whiteout.’ Flat light conditions are usually accompanied by overcast skies inhibiting visual cues. Flat light can completely obscure features of the terrain, creating an inability to distinguish distances and closure rates.” According to the AIM, “flat light conditions can lead to a whiteout environment quite rapidly, and both atmospheric conditions are insidious; they sneak up on you as your visual references slowly begin to disappear.” ## Aircraft - Registration: [N66036](https://openairdocs.org/deregistered/N66036-2009-07-27), registration cancelled 2009-07-27, S/N 18052908, built 1977 (OpenAirDocs) - Reported make and model: Cessna 180 - Registry model: [Cessna 180K](https://openairdocs.org/model/cessna-180k) (registry code 2072624) (OpenAirDocs) - Registry engine: [Continental O-470 series](https://openairdocs.org/engine/continental-o-470-series) (registry code 17026, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 1805298 - Airframe hours: 2980 - Engines: Continental O-470 230 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: C. Kenneth Moon - Airworthiness certificate: Standard, Normal - Last inspection: Annual, September 1, 2007, 50 hours before - Departed: PAKK, Koyuk, AK - Destination: WMO, White Mountain, AK ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 72; injuries: none; airline transport, flight engineer, commercial, flight instructor; airplane ratings: single-engine sea, multi-engine sea, single-engine land, multi-engine land; instrument ratings: helicopter, airplane; medical: class 1, without waivers/limitations; last flight review January 1, 2008; seat: left; flight hours: 19,930 total, 2,300 in this make and model, 17,000 as pilot in command, 43 in the last 90 days, 35 in the last 30 days, 5 in the last 24 hours ## Weather - Conditions: Instrument (IMC), Day - Wind: calm - Visibility: 5 statute miles - Lowest ceiling: 3,000 ft indefinitevv ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20080311014039A](https://openairdocs.org/incident/20080311014039A), Mar 11, 2008: Cessna 180K, White Mountain, AK, Destroyed. (-23) [privacy data omitted] on March 11, 2008, at approximately 10:00 am local time, the pilot-in-command obtained weather information from the iditarod air… ## Other investigations on N66036 (1) From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. - [NTSB ANC91LA035](https://openairdocs.org/ntsb/ANC91LA035), Mar 10, 1991: Cessna 180K (N66036), Amos Lakes, AK, substantial damage. Probable cause: THE PILOT'S SELECTION OF TERRAIN THAT WAS ROUGH, SNOW-COVERED AND ICY FOR TAKEOFF. From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.