# NTSB ANC98GA036: Cessna 185F, N5485R, Nightmute, AK, April 9, 1998 - Type: NTSB accident investigation - Classification: Accident · Fatal · Final report - Date: April 8, 1998, 16:55 local (Apr 9, 1998, 00:55 UTC) - Place: Nightmute, AK - Coordinates: 60.489894, -164.810806 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=60.4899&lon=-164.8108&mi=10 - Phase of flight: [Unknown](https://openairdocs.org/ntsb-phases/990) (OpenAirDocs' grouping) - Highest injury: Fatal - Injuries: 2 fatal - Status: Completed, report August 10, 2000 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - NTSB case key (mKey): 3097 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC98GA036 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/3097/pdf - Page: https://openairdocs.org/ntsb/ANC98GA036 ## Probable cause The pilot's continued VFR flight into instrument meteorological conditions which resulted in spatial disorientation and subsequent loss of aircraft control. Factors in the accident were meteorological conditions consisting of low ceilings, and blowing snow, and the pilot's failure to obtain a preflight weather briefing. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - In flight encounter with weather, unknown - weather condition - low ceiling (contributing factor) - preflight briefing service - not obtained, pilot in command (contributing factor) - weather condition - snow (contributing factor) - vfr flight into imc - continued, pilot in command (cause) - Loss of control - in flight, descent - uncontrolled - aircraft control - not maintained, pilot in command (cause) - spatial disorientation, pilot in command (cause) - In flight collision with terrain/water, descent - uncontrolled - terrain condition - snow covered ## Analysis The commercial pilot departed on a CFR Part 135/government flight for a remote coastal village to pick up the sole passenger. Just before landing at the village, light snow began to fall, and the wind conditions increased to about 20 knots. There was no evidence the pilot obtained a weather briefing. The area forecast included isolated ceilings below 1,000 feet, and visibilities below 3 miles in blowing snow and mist from offshore. The forecast wind conditions included 20 knots to 40 knots from offshore. Airmets were issued for moderate low level turbulence, mountain obscuration, strong surface winds along the coast, and moderate rime icing in clouds. When the airplane departed the village on the accident flight, a resident said the visibility was 1/4 to 1/2 mile in blowing snow. The flight did not reach the destination. The wreckage was located 8 miles away in snow covered terrain after two days of blizzard conditions. The airplane collided with the ground in a near vertical attitude, and exhibited high speed destruction. An examination of the engine did not reveal any preimpact malfunction. Evidence of engine combustion, heat, and rotation were noted during the engine examination. ## Factual narrative HISTORY OF FLIGHT On April 8, 1998, about 1655 Alaska daylight time, a wheel equipped Cessna 185F, airplane, N5485R, was destroyed when the airplane collided with remote, snow covered terrain, about 5 miles west-northwest of Nightmute, Alaska. The airplane was being operated as a visual flight rules (VFR) cross-country U.S. Government flight with Y-K Aviation Inc., Bethel, Alaska. The certificated airline transport pilot, and the sole passenger, received fatal injuries. VFR company flight following procedures were in effect. The flight originated at the Toksook Bay Airport, Toksook Bay, Alaska, about 1650, and was en route to Bethel. The pilot departed Bethel, Alaska, about 1545 for Toksook Bay, located on Nelson Island, to pick up the passenger. The passenger, an employee of the U.S. Department of Health and Human Services, Alaska Native Health Service, chartered Y-K Aviation for the flight to Bethel to attend a conference. A resident of the Village of Toksook Bay drove the passenger out to the airport about 1630. The resident reported the weather conditions at the time included light snow and wind. After picking up the passenger, the airplane departed for Bethel. Another resident reported that snow began falling just before the accident airplane arrived in Toksook Bay. The winds were less than 20 knots from the west-southwest. He watched the airplane depart, and climb to about 200 feet above the ground. The resident then lost sight of the airplane due to visibility conditions that he described as between 1/4 and 1/2 mile. The flight did not reach Bethel, and was reported overdue at 2343. Blizzard weather conditions prevented search personnel from Toksook Bay, and Nightmute, Alaska, from beginning an immediate search. The wreckage was located on April 9, 1998, about 1622. The accident location is about 8 1/2 miles east of Toksook Bay. The accident occurred during the hours of daylight, at latitude 60 degrees, 30.978 minutes north, and longitude 164 degrees, 49.252 minutes west. CREW INFORMATION The pilot held an airline transport pilot certificate with an airplane single-engine land rating. The pilot also held commercial pilot privileges with an airplane multiengine rating, and private pilot privileges with an airplane single-engine sea rating. The most recent first-class medical certificate was issued to the pilot on January 15, 1998, and contained no limitations. No personal flight records were located for the pilot. The aeronautical experience listed on page 3 of this report was obtained from a review of the airmen Federal Aviation Administration (FAA) records on file in the Airman and Medical Records Center located in Oklahoma City. On the pilot's application for medical certificate, dated January 15, 1998, the pilot indicated that his total aeronautical experience consisted of about 8,800 hours, of which 650 were accrued in the previous 6 months. The pilot held a single pilot Part 135 air carrier certificate. He completed a Part 135 proficiency check ride with an FAA inspector on August 29, 1997. AIRCRAFT INFORMATION The airplane's tachometer and hour meter were destroyed. An examination of the maintenance records revealed the most recent annual inspection of the engine and airframe, was accomplished on December 5, 1997. The last recorded inspection of the engine and airframe was a 100-hour inspection, completed on March 27, 1998. At that time, the airplane had accrued 6,125.5 hours. The engine was overhauled on February 18, 1997, by Penn Yan Aero Inc., and had accrued 1,189.9 hours since the overhaul. METEOROLOGICAL INFORMATION The closest official weather observation station is Mekoryuk, Alaska, which is 43 nautical miles west-southwest of the accident site. Mekoryuk is located on Nunivak Island which is separated from the mainland by the Etolin Strait of the Bering Sea. On April 8, 1998, at 1537, an unaugmented automated weather observation system (AWOS) station was reporting, in part: Wind, 170 degrees (true) at 24 knots; visibility, 1 3/4 statute miles; clouds, clear below 12,000 feet; temperature, 35 degrees F; dew point, 10 degrees F; altimeter, 29.75 inHg. Hooper Bay, Alaska, is located 72 miles northwest of the accident site. At 1541, an unaugmented AWOS was reporting, in part: Wind, 130 degrees (true) at 28 knots; visibility, 1/2 statute mile; clouds, 100 feet overcast; temperature, 23 degrees F; dew point, missing; altimeter, 29.80 inHg. Bethel, Alaska, is located 90 nautical miles east of the accident site. At 1653, an Aviation Routine Weather Report (METAR) was reporting in part: Wind, 170 degrees (true) at 17 knots; visibility, 30 statute miles; clouds, 3,300 feet broken, 6,000 feet overcast; temperature, 34 degrees F; dew point, 20 degrees F; altimeter, 29.99 inHg; remarks, virga. An NTSB meteorologist conducted an investigation of the weather conditions around the accident location. The weather study revealed a warm front extending from the central Alaska Peninsula, northwestward over the Bristol Bay, to a little east of Nunivak Island. Moderate to strong southeasterly, to southerly winds, and overcast clouds were present over the coastal areas of western Alaska. An area forecast for the Yukon-Kuskokwim Delta, issued on April 8, 1998, at 1200, and valid from 1200 until 0000, was reporting, in part: Through 1800, few clouds at 2,000 feet, 5,000 feet scattered, 10,000 feet broken, tops at 12,000 feet, widely separated layers above, tops at 25,000 feet. Temporary conditions, 2,000 feet broken, 5,000 feet overcast, visibility 5 statute miles in light snow and mist, west of a line from Hooper Bay to Cape Newenham. Isolated ceilings below 1,000 feet with visibilities below 3 statute miles in mist and freezing fog, tops at 4,000 feet east of line from Hooper Bay to Bethel. Beyond 1800, clouds and weather conditions, 2,000 feet scattered, 5,000 feet broken, 10,000 feet broken, tops at 12,000 feet, separated layers above 30,000 feet. Temporary conditions, 2,000 feet overcast, visibility 4 statute miles in light snow and mist. Isolated ceilings below 1,000 feet, visibilities below 3 statute miles in light snow, blowing snow and mist from offshore. Surface winds from the southeast at 20 knots with gusts to 40 knots from offshore. Outlook, valid from April 9, 1998, at 0000 to 1800, marginal VFR ceilings with rain, snow, mist, and wind. Airmets are valid until 1800. Airmet for Turbulence, Temporary moderate turbulence between 20,000 and 32,000 feet, no changes. After 1800, isolated moderate turbulence within 3,000 feet agl in the vicinity of rough terrain. Icing and freezing level, temporary light rime icing in clouds from the surface to 12,000 feet. After 1900, isolated moderate rime icing in clouds from 2,000 to 10,000 feet. Freezing level is near the surface. An amended area forecast for the Yukon-Kuskokwim Delta was issued on April 8, 1998, at 1455, and valid until 0000, stated, in part: Airmet for IFR and mountain obscuration, west of a line from Emmonak to Cape Newenham. Temporary ceilings below 1,000 feet, visibility below 3 statute miles in light snow, mist, and freezing fog. All sections, mountains obscured, no changes. West of a line from Emmonak to Cape Newenham, 1,500 feet broken, 3,000 feet overcast, merging layers to 10,000 feet, separated layers above, tops at 30,000 feet. Visibility, 3 statute miles in light snow, surface winds from the southeast at 20 knots, gusts to 35 knots. East of line from Emmonak to Cape Newenham, 2,500 feet scattered, 5,000 feet broken, 10,000 feet broken, tops at 12,000 feet, widely separated layers above, tops at 25,000 feet. Temporary conditions, 2,500 feet broken, widely scattered, visibility 5 statute miles in light snow showers and mist. Surface winds from the southeast with gusts to 25 knots through channels. Outlook, valid from April 9, 1998, at 0000 to 1800, west of a line fro ## Aircraft - Registration: [N5485R](https://openairdocs.org/deregistered/N5485R-2017-02-17), registration cancelled 2017-02-17, S/N 18503038, built 1976 (OpenAirDocs) - Reported make and model: Cessna 185F - Registry model: [Cessna A185F](https://openairdocs.org/model/cessna-a185f) (registry code 2072821) (OpenAirDocs) - Registry engine: [Continental IO-520 series](https://openairdocs.org/engine/continental-io-520-series) (registry code 17032, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 18503038 - Airframe hours: 6126 - Engines: Continental IO-520-D 300 horsepower reciprocating - Damage: Destroyed - Flight: Public use - Operator: Alaska Native Health Service - Registered owner: Y-K Aviation Inc. - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, March 27, 1998 - Departed: OOK, TOKSOOK BAY, AK - Destination: BET, BETHEL, AK - Flight plan: Company VFR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 35; commercial, airline transport, private; airplane ratings: single-engine land, multi-engine land, single-engine sea; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: left; toxicology performed; flight hours: 8,800 total ## Weather - Conditions: Instrument (IMC), Day - Wind: 170° at 24 knots - Visibility: 1.34 statute miles - Lowest ceiling: none - Temperature: 36 °F, dew point 28 °F - Altimeter: 29.00 inHg - Observed at: PAM, 43 nm away ## 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 19980408006389A](https://openairdocs.org/incident/19980408006389A), Apr 8, 1998: Cessna A185F, Nightmute, AK, Destroyed, 2 fatal. (.4)The commercial pilot departed on a CFR part 135/government flight for a remote coastal village to pick up the sole passenger. Just before landing at the… ## Other investigations on N5485R (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 ANC79DAG19](https://openairdocs.org/ntsb/ANC79DAG19), Sep 9, 1978: Cessna 185 (N5485R), Farewell, AK, substantial damage 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.