# NTSB FTW98LA176: Cessna P206B, N4728F, Riverton, WY, April 7, 1998 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Limited investigation · Final report - Date: April 7, 1998, 11:55 local (17:55 UTC) - Place: Riverton, WY - Coordinates: 43.030311, -108.409576 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=43.0303&lon=-108.4096&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: Serious injuries - Injuries: 1 serious, 1 minor, 2 uninjured - Status: Completed, report October 30, 1998 - Report: Approved by Office Director - NTSB case key (mKey): 20573 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW98LA176 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/20573/pdf - Page: https://openairdocs.org/ntsb/FTW98LA176 ## Probable cause continued flight by the pilot into instrument meteorological conditions (IMC), and his failure to maintain sufficient altitude from terrain, while manuevering to reverse direction. Related factors were: the adverse weather conditions, mountainous terrain, and the pilot's lack of instrument experience. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - In flight encounter with weather, cruise - normal - weather condition - low ceiling (contributing factor) - weather condition - drizzle/mist (contributing factor) - weather condition - snow (contributing factor) - weather condition - obscuration (contributing factor) - vfr flight into imc - continued, pilot in command (cause) - lack of total instrument time, pilot in command (contributing factor) - In flight collision with terrain/water, maneuvering - turn to reverse direction - terrain condition - mountainous/hilly (contributing factor) - altitude/clearance - not maintained, pilot in command (cause) ## Analysis The pilot obtained a weather briefing before departing on a flight from Rock Springs, WY, to Broadus, MT. He was told that Gillette, WY, and Billings, MT, were reporting instrument meteorological conditions (IMC), and that no weather was available for Riverton, WY. Since visual meteorological conditons (VMC) prevailed at Rock Springs, he made a decision to takeoff and assess the weather en route. While in cruise flight, the aircraft penetrated a line of light drizzle and snow showers. While attempting to reverse direction, the airplane collided with terrain. ## Factual narrative On April 7, 1998, approximately 1155 mountain daylight time, a Cessna P206B, N4728F, was substantially damaged when it collided with terrain while maneuvering to reverse direction 19 miles southeast of Riverton, Wyoming. The commercial pilot was seriously injured, one passenger sustained minor injuries, and two passengers were not injured. Instrument meteorological conditions prevailed, and no flight plan was filed for the personal flight being conducted under Title 14 CFR Part 91. The flight originated at Rock Springs, Wyoming, approximately 30 minutes prior to the accident. The following is based on the accident report submitted by the pilot. He and his passengers had flown from Utah and landed at Rock Springs, Wyoming. He obtained a weather briefing and was told that Gillette, Wyoming, and Billings, Montana, were reporting instrument meteorological conditions, and no weather was available for Riverton, Wyoming. Since visual meteorological conditions prevailed at Rock Springs, he made the decision to proceed and assess the weather en route. While in cruise flight, the aircraft penetrated a line of light drizzle and snow showers. The pilot noticed "what appeared to be a limitation to forward visibility" ahead of him, but due to the flat light (sic) conditions, he underestimated his distance from the terrain. As a result, he did not slow the airplane down from cruise speed in enough time, and subsequently lost visual references for approximately 20 to 30 seconds. After he had regained visual conditions, he attempted to slow the aircraft down and turn 180 degrees, following a return course on his Global Positioning System. As he established himself on the course, he noticed a hill in front of their path and began to turn away from it to the left. In an attempt to shorten his turn, he added flaps. The left lower wing struck a rise in the terrain, and the airplane impacted the ground. In his accident report, the pilot said that there was 1 mile visibility, a broken ceiling between 500 to 1,000 feet, and moderate snow showers. The left wing was torn off, and there was damage to the engine, the right wing, the nacelle, landing gear, and fuselage. ## Aircraft - Registration: [N4728F](https://openairdocs.org/deregistered/N4728F-2013-10-23), registration cancelled 2013-10-23, S/N P206-0328, built 1966 (OpenAirDocs) - Reported make and model: Cessna P206B - Registry model: [Cessna P206B](https://openairdocs.org/model/cessna-p206b) (registry code 2073309) (OpenAirDocs) - Registry engine: [Continental IO-520 series](https://openairdocs.org/engine/continental-io-520-series) (registry code 17032, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: P2060328 - Airframe hours: 6251 - Engines: Continental I0-520 285 horsepower reciprocating - Damage: Destroyed - Flight: Personal, Part 91 - Registered owner: Jeffrey G. Wash - Airworthiness certificate: Standard, Normal - Last inspection: Annual, June 10, 1997 - Departed: RKS, ROCK SPRINGS, WY - Destination: BDX, BROADUS, MT ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 37; commercial; airplane ratings: single-engine land; medical: class 2, valid medical--no waivers/lim.; seat: left; flight hours: 3,200 total, 1,500 in this make and model, 3,100 as pilot in command, 19 in the last 90 days, 17 in the last 30 days, 5 in the last 24 hours ## Weather - Conditions: Instrument (IMC), Day - Wind: 250° at 7 knots - Visibility: 30 statute miles - Lowest ceiling: 3,700 ft broken - Temperature: 59 °F, dew point 41 °F - Altimeter: 30.00 inHg - Observed at: RIV, 19 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 19980407011359A](https://openairdocs.org/incident/19980407011359A), Apr 7, 1998: Cessna P206B, Riverton, WY, Destroyed. On approach deviated due snow area. Too slow. Stalled. Struck trees and deep snow. ELT battery out of date. (.4)the pilot obtained a weather briefing before… 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.