# NTSB ANC00FA018: Cessna 207, N1747U, Bethel, AK, December 7, 1999 - Type: NTSB accident investigation - Classification: Accident · Fatal · Field investigation · Final report - Date: December 7, 1999, 13:00 local (17:00 UTC) - Place: Bethel, AK - Coordinates: 60.809936, -161.84967 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=60.8099&lon=-161.8497&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: Fatal - Injuries: 6 fatal - Status: Completed, report April 18, 2001 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - NTSB case key (mKey): 48511 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC00FA018 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/48511/pdf - Page: https://openairdocs.org/ntsb/ANC00FA018 ## Probable cause The pilot's continued VFR flight into instrument meteorological conditions. Factors associated with the accident were low ceilings, fog, and snow-covered terrain. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - In flight encounter with weather, cruise - weather condition - low ceiling (contributing factor) - weather condition - fog (contributing factor) - vfr flight into imc - continued, pilot in command (cause) - In flight collision with terrain/water, cruise - terrain condition - snow covered (contributing factor) ## Analysis The airline transport pilot departed on a CFR Part 135 scheduled passenger flight to a remote coastal village. When the flight did not return, an aerial search was initiated. The wreckage was located the following day along the pilot's intended route, about 49 miles from the departure airport. The airplane had collided with flat, featureless, snow-covered, terrain. A pilot that departed about one minute after the accident airplane's departure, had a similar route of flight. He characterized the weather conditions along the accident airplane's route as overcast, with ceilings ranging between 2,500 and 4,500 feet. He said that as he approached the area of the accident, he encountered 'a wall of weather' starting from the ground, with tops at 1,500 feet. He added that visibility was low, with fog and varied layers of cloud cover. The pilot stated that he changed his route in order to avoid the worsening weather conditions. He added that with satisfactory weather conditions, and given the intended destination of the accident airplane, the standard route of flight would be directly over the location of the accident site. No preaccident anomalies were noted with the accident airplane. ## Factual narrative HISTORY OF FLIGHT On December 7, 1999, about 1300 Alaska standard time, a wheel equipped Cessna 207 airplane, N1747U, was destroyed when the airplane collided with remote, snow-covered terrain, about 49 nautical miles west-southwest of Bethel, Alaska, at 60 degrees, 37 minutes north latitude, 163 degrees, 28 minutes west longitude. The airplane was operated by Grant Aviation, Inc., Anchorage, Alaska. The flight was being conducted under Title 14, CFR Part 135, as scheduled commuter Flight 261, when the accident occurred. The certificated airline transport pilot, and the five passengers aboard, all received fatal injuries. Company flight following procedures were in effect. The flight originated at the Bethel Airport, Bethel, at 1236, and was en route to Nightmute, Toksook, and Tununak, Alaska. The flight failed to return to Bethel by 1530, and company dispatch personnel initiated a phone search. They discovered that the flight had never reached Nightmute, the first scheduled destination. A company aerial search was initiated about 1600. The flight was officially reported overdue to the Federal Aviation Administration (FAA) at 1713. Personnel from the Alaska State Troopers, Civil Air Patrol, and Alaska Air National Guard, were dispatched to search the route of flight, but were unable to locate the missing airplane. The wreckage was located on December 8, about 1330, along the anticipated route of flight to Nightmute. There was no emergency locator transmitter (ELT) signal from the airplane. CREW INFORMATION The pilot held an airline transport pilot certificate with airplane single-engine land, and multiengine land ratings. He also held a flight instructor certificate with airplane single-engine, and multiengine land, airplane ratings. His most recent first-class medical certificate was issued on July 20, 1999, and contained no limitations. The pilot was hired by the company on July 12, 1999. On August 6, 1999, the pilot completed his initial Part 135 check ride in accordance with FAR 135.293 and 135.299. According to the Pilot/Operator report (NTSB form 6120.1/2) submitted by the operator, the pilot's aeronautical experience consisted of 2,255 hours, of which 390 hours were accrued in the accident airplane make and model. In the preceding 90 and 30 days prior to the accident, the report listed a total of 301 and 66 hours, respectively. According to the operator, on the day preceding the accident, the pilot accrued 3.0 hours of flight time. AIRCRAFT INFORMATION The airplane had accumulated a total time in service of 10,363.5 hours. An examination of the maintenance records revealed the most recent annual inspection of the engine and airframe was accomplished on April 28, 1999. The last recorded inspection of the engine and airframe was a 100-hour inspection, completed on November 13, 1999, 45.0 hours before the accident. The engine was overhauled on September 24, 1999, by Aero Recip Alaska, Inc., and had accrued 196.9 hours since overhaul. METEOROLOGICAL INFORMATION The closest weather observation station is Bethel, which is located about 49 nautical miles east-northeast of the accident site. On December 7, at 1253, an Aviation Routine Weather Report (METAR) was reporting in part: Sky conditions and ceiling, 2,000 overcast; visibility, 10 statute miles; wind, calm; temperature, 0 degrees F; dew point, minus 7 degrees F; altimeter, 29.89. Hooper Bay, Alaska, is located about 95 nautical miles northwest of the accident site. At 1255, an unaugmented AWOS was reporting, in part: Wind, 100 degrees (true) at 12 knots; visibility, missing; clouds, 7,500 feet broken; temperature, minus 4 degrees F; dew point, minus 11 degrees F; altimeter, 29.87 inHg. Mekoryuk, Alaska, is located about 84 nautical miles south-southwest of the accident site. At 1255, an unaugmented AWOS was reporting, in part: Wind, 170 degrees (true) at 13 knots; visibility, 10 statute miles; clouds, 1,800 feet scattered, 2,500 feet overcast, 4,600 feet overcast; temperature, 12 degrees F; dew point, 9 degrees F; altimeter, 29.83 inHg. An NTSB meteorologist reviewed the weather conditions around the accident location. The weather study revealed a trough of low pressure located along 150 degrees west longitude with two low pressure centers over the northern Gulf of Alaska. In addition, the study indicated a weak ridge of high pressure extending from the Bethel area westward to the Bering Sea. A complete copy of his report is appended. An area forecast for the Yukon-Kuskokwim Delta, issued on December 7, 1999, at 1145, and valid until 0000, was forecasting, in part: Clouds and weather, 1,500 feet scattered, 9,000 feet broken, tops at 11,000 feet, with occasional 1,500 feet broken. An AIRMET valid until 1800, was forecasting mountain obscuration in clouds and precipitation along the pilot's planned route of flight. An amended terminal forecast for Bethel, valid from 1041 on December 7, was forecasting, in part: Wind, 190 degrees at 6 knots: Visibility greater that 6 statute miles; clouds and sky condition, 1,500 feet scattered, 2,500 feet overcast. Temporary changes expected between the valid forecast times, Visibility, 3 statute miles, light snow showers; clouds and sky condition, 4000 feet broken. A pilot that departed from Bethel about one minute after the accident airplane's departure, had a similar route of flight. He characterized the weather conditions between Bethel and the accident site as overcast with ceilings ranging between 2,500 and 4,500 feet. He said that as he approached the accident site, he encountered "a wall of weather" starting from the ground, with the tops at 1,500 feet. He added that visibility was low with fog and varied layers of cloud cover. The pilot stated that he changed his route in order to avoid worsening weather conditions. He added that with satisfactory weather conditions, and given the intended destination of the accident airplane, the standard route of flight would be directly over the location of the accident site. WRECKAGE AND IMPACT INFORMATION The National Transportation Safety Board investigator-in-charge examined the wreckage at the accident site on December 9, 1999. The airplane was located in an area of flat, featureless, and snow-covered terrain. High winds, snow, fog, and sub-zero temperatures limited the available time at the scene. The investigator-in-charge returned to the accident site on May 22, 2000, and completed the on scene examination of the wreckage. The main wreckage debris path was oriented on a 245 degree heading, and was about 195 feet long. (All headings/bearings noted in this report are magnetic). The first piece of airplane wreckage discovered along the debris path was a broken red navigation lens, and the left wingtip. About 24 feet from the left wingtip debris was a crater, measuring about 5 feet in diameter, and 3 feet deep. The engine, engine firewall, lower cockpit floor, and propeller assembly, were within the crater. The engine sustained extensive impact and fire damage to the underside, and front portion of the engine. The exhaust tubes were extensively crushed, bent, and folded, producing sharp creases that were not cracked or broken along the creases. The propeller assembly separated from the engine crankshaft. The propeller blades and propeller hub were located within the 3 foot deep crater. Removal of the propeller assembly from the crater revealed the spinner was crushed aft, and folded and formed around the shape of the propeller hub assembly. The first propeller blade was observed underneath the engine, and bent aft. The two remaining propeller blades had minor leading edge gouging, and extensive "S" bending. Extensive fuselage fragmentation was evident along the debris path between the crater and the main wreckage. A postcrash fire incinerated the airpl ## Aircraft - Registration: [N1747U](https://openairdocs.org/deregistered/N1747U-2006-09-25), registration cancelled 2006-09-25, S/N 20700347, built 1976 (OpenAirDocs) - Reported make and model: Cessna 207 - Registry model: [Cessna 207](https://openairdocs.org/model/cessna-207) (registry code 2073602) (OpenAirDocs) - Registry engine: [Continental IO-520 series](https://openairdocs.org/engine/continental-io-520-series) (registry code 17032, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 20700347 - Airframe hours: 10363 - Engines: Continental IO-520F 300 horsepower reciprocating - Damage: Destroyed - Fire: On-Ground - Flight: Part 135 - Operator: Grant Aviation, Inc. - Registered owner: Bruce E. Larson - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, November 13, 1999, 45 hours before - Departed: BET, AK - Destination: IGT, NIGHTMUTE, AK - Flight plan: Company VFR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 33; flight instructor, airline transport, commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: left; toxicology performed; flight hours: 2,255 total, 390 in this make and model, 2,150 as pilot in command, 301 in the last 90 days, 66 in the last 30 days, 3 in the last 24 hours ## Weather - Conditions: Instrument (IMC), Day - Wind: calm - Visibility: 10 statute miles - Lowest ceiling: 2,000 ft overcast - Temperature: -0 °F, dew point -0 °F - Altimeter: 29.00 inHg - Observed at: BET, 49 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 19991207046769A](https://openairdocs.org/incident/19991207046769A), Dec 7, 1999: Cessna 207, Bethel, AK, No damage, 6 fatal. (-23) On December 7, 1999, about 1300 Alaska standard time, a wheel equipped Cessna 207 airplane, N1747U, was destroyed when the airplane collided with remote,… ## Other investigations on N1747U (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 ANC97LA042](https://openairdocs.org/ntsb/ANC97LA042), Mar 27, 1997: Cessna 207 (N1747U), Grayling, AK, substantial damage. Probable cause: The partial loss of engine power due to a fractured connecting rod bolt, which was precipitated by fatigue. A factor associated with the accident was the snow covered terrain in the emergency landing… 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.