# NTSB DEN04FA079: Mooney M20K, N231DL, Pinedale, WY, May 23, 2004 - Type: NTSB accident investigation - Classification: Accident · Fatal · Field investigation · Final report - Date: May 23, 2004, 11:39 local (17:39 UTC) - Place: Pinedale, WY - Coordinates: 43.18111, -109.656944 - Nearby events: https://openairdocs.org/map.md?lat=43.1811&lon=-109.6569&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: Fatal - Injuries: 3 fatal - Status: Completed, report September 13, 2005 - Report: Approved by Office Director - Parties: FAA CPR FSDO - NTSB case key (mKey): 59318 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN04FA079 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/59318/pdf - Page: https://openairdocs.org/ntsb/DEN04FA079 ## Probable cause The pilot's inadvertent flight into adverse weather conditions, and his failure to maintain terrain clearance while maneuvering. Contributing factors were the downdraft, the snow shower weather and mountainous terrain. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - In flight encounter with weather, cruise - flight into adverse weather - inadvertent, pilot in command (cause) - weather condition - downdraft (contributing factor) - weather condition - snow (contributing factor) - In flight collision with terrain/water, maneuvering - clearance - not maintained, pilot in command (cause) - terrain condition - mountainous/hilly (contributing factor) ## Analysis The non-instrument rated private pilot had been airborne for approximately 3 hours when he approached the Wind River Range in central Wyoming. Radar data indicated that he descended from 15,500 feet to 14,300 feet (because of weather) to cross the continental divide at Gannett Peak, elevation 13,804 feet,. Radar data indicates that approximately 20 seconds later, the airplane was in an approximate 4,200 feet per minute rate of descent. Satellite imagery and NEXRAD Doppler data suggest that at the pilot's ground track location, the mountain was experiencing light to intermittent snow showers according to the NTSB meteorologist. No endorsements could be found in the pilot's flight logbook to indicate that he had received any mountain flying training. Search and rescue teams found the airplane 3 days later. No evidence of a mechanical failure was found. ## Factual narrative HISTORY OF FLIGHT On May 23, 2004, at 1139 mountain daylight time, a Mooney M20K, N231DL, was destroyed when it impacted terrain while maneuvering in the Wind River Range, near Pinedale, Wyoming. The private pilot and his two passengers were fatally injured. The pilot/owner of the airplane was operating it under Title 14 CFR Part 91. Visual meteorological conditions prevailed for the personal, cross-country flight that originated from Sunriver, Oregon, at approximately 0800. The meteorological (visibility) conditions could not be determined at the accident site. No flight plan had been filed, but family members said the destination was Scottsbluff, Nebraska. The pilot requested flight following from Seattle Air Route Traffic Control Center (ARTCC) soon after takeoff. During the flight, he frequently requested updated weather reports for his route of flight from Federal Aviation Administration (FAA) Air Traffic Control (ATC) personnel. At 1103, ATC tapes documented that the pilot said that he was deviating to avoid weather, and at 1117 he said his intention was to continue to Riverton, Wyoming, for a fuel stop. At 1136, ATC radar data indicates that the airplane was approaching the Wind River Range at 15,700 feet. At 1138:52, the airplane crossed over Gannett Peak (elevation 13,804 feet), which is on the continental divide and is the highest peak in Wyoming. At 1139:20, ATC radar recorded its last return from the airplane. The last two radar returns suggest that the airplane was in a descent of approximately 4,200 feet per minute. Search and rescue teams found the airplane 3 days later. PERSONNEL INFORMATION The Federal Aviation Administration's (FAA) records indicate that the pilot got his private pilot's license on March 14, 1995; he was not instrument rated. The pilot had taken an FAA required flight medical (third class) on April 16, 2002; it was good for two years. He had an FAA required flight review endorsement dated June 10, 2002. On an insurance application, dated March 6, 2004, he reported that he had 600 hours of total flight experience, and 400 hours in make and model. The NTSB Investigator-In-Charge reviewed the pilot's flight logbook and found no endorsements to indicate whether the pilot had ever received any mountain flying training. AIRCRAFT INFORMATION The airplane was a single engine, propeller-driven, four seat airplane, which was manufactured by Mooney Aircraft Corporation in 1979. It was powered by a Continental TSIO-360-LB1B, six cylinder, reciprocating, horizontally opposed, direct drive, air cooled, fuel injected, turbo-charged engine, which had a maximum takeoff rating of 210 horsepower at sea level. The airplane received its last annual inspection on June 21, 2003, at that time, the Hobbs meter read 1,337 hours and the airframe had 3,564 hours on it. The airplane was equipped with a Global Positioning System (GPS), and an oxygen system. METEOROLOGICAL INFORMATION At 1153, the weather conditions at Big Piney, Wyoming (BPI; elevation 6,990 feet), 200 degrees for 43 nautical miles (nm) from the accident site, was as follows: wind 210 degrees at 14 knots gusting to 20 knots; visibility 10 statue miles (sm); cloud condition scattered at 3,900 feet, broken at 5,500 feet, and broken at 6,500 feet; temperature 46 degrees Fahrenheit; dew point 37 degrees Fahrenheit; altimeter setting 29.83 inches. At 1156, the weather conditions at Riverton, Wyoming (RIW; elevation 5,525 feet), 085 degrees for 50 nm from the accident site, were as follows: wind 200 degrees at 16 knots gusting 24 knots; visibility 10 sm; cloud condition scattered at 8,500 feet; temperature 59 degrees Fahrenheit; dew point 32 degrees Fahrenheit; altimeter setting 29.73 inches. The sounding data at Riverton, Wyoming, at 0600 on the day of the accident, indicated that the wind at 12,000 feet was 270 degrees at 26 knots, at 13,500 feet it was 273 degrees at 26 knots, and at 16,000 feet it was 260 degrees at 26 knots. Satellite imagery showed that the Wind River Range was covered by clouds; the bottoms could not be determined. NEXRAD Doppler weather radar (WSR-88-D) data indicates light to moderate precipitation (snow) in the northwest half of the Wind River Range, and intermittent precipitation (snow) in the southeast half of the Wind River Range. WRECKAGE AND IMPACT INFORMATION The airplane was found on very rugged mountainous terrain (N43 degrees, 11', 28"; W109 degrees, 36', 56"; elevation 11,000 feet) which was barren of any vegetation. The bearing from the last radar hit to the impact site was approximately 100 degrees, and a distance of between 4,000 to 5,000 feet away. Some airplane debris was found scattered in the valley below, but the main wreckage was found buried in deep snow half way up a rocky, 45 degree up sloping scree field. Due to the extreme nature of the airplane's impact, no control continuity or cockpit documentation was possible. Salvage personnel believed that all the airplane's major components were accounted for at the accident site. No preimpact engine or airframe anomalies, which might have affected the airplane's performance, were identified. MEDICAL AND PATHOLOGICAL INFORMATION The Fremont County Coroner, from Riverton, Wyoming, ordered an autopsy to be done on the pilot, by a forensic pathology consultant, at McKee Medical Center, Loveland, Colorado. This was accomplished on June 10, 2004. The FAA's Civil Aeromedical Institute (CAMI) in Oklahoma City, Oklahoma, performed toxicology tests on the pilot. According to CAMI's report (#200400128001), carbon monoxide and cyanide test were not performed. The tests for drugs were negative, and the positive volatiles test results were believed to be due to postmortem ethanol formation and not from the ingestion of ethanol. ADDITIONAL DATA The NTSB investigator-In-Charge did not travel to the accident site due to severe weather conditions. An FAA inspector from Casper, Wyoming, did make it to the accident site and documented it. The airplane's wreckage was retrieved to Beegles Aircraft Service, Inc., Greeley, Colorado, in mid July. The airplane, including all components and logbooks, was released to a representative of the owner's insurance company on September 16, 2004. ## Aircraft - Registration: [N231DL](https://openairdocs.org/deregistered/N231DL-2004-07-30), registration cancelled 2004-07-30, S/N 25-0010, built 1978 (OpenAirDocs) - Reported make and model: Mooney M20K - Registry model: [Mooney M20K](https://openairdocs.org/model/mooney-m20k) (registry code 5870220) (OpenAirDocs) - Registry engine: [Continental TSIO-360 series](https://openairdocs.org/engine/continental-tsio-360-series) (registry code 17019, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 25-0010 - Airframe hours: 3564 - Engines: Continental TSIO-360-LB1B 210 horsepower reciprocating - Damage: Destroyed - Flight: Personal, Part 91 - Registered owner: Lashley Auto Sales, Inc. - Airworthiness certificate: Standard, Normal - Last inspection: Annual, June 21, 2003 - Departed: S21, Sunrise, OR - Destination: RIW, Riverton, WY ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 49; injuries: fatal; private; airplane ratings: single-engine land; medical: class 3; last flight review June 10, 2002; seat: left; toxicology performed; flight hours: 600 total, 400 in this make and model, 5 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 200° at 16 knots, gusting 24 - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 59 °F, dew point 32 °F - Altimeter: 29.72 inHg - Observed at: RIW, 50 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 20040523011799A](https://openairdocs.org/incident/20040523011799A), May 23, 2004: Mooney M20K, Pinedale, WY, Destroyed, 3 fatal. (-23) During a cross country flight from sun river, or to scottsbuff, NE, the aircraft was lost on radar at 14,000 feet and in a left hand spiral. The aircraft… 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.