# NTSB WPR09CA193: Piper PA-28-140, N945RH, Dubois, WY, April 13, 2009 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Data collection · Final report - Date: April 13, 2009, 15:10 local (21:10 UTC) - Place: Dubois, WY - Coordinates: 43.752223, -110.067222 - Nearby events: https://openairdocs.org/map.md?lat=43.7522&lon=-110.0672&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute: Windshear or thunderstorm](https://openairdocs.org/ntsb-events/390) - Highest injury: Minor injuries - Injuries: 2 minor - Status: Completed, report July 14, 2009 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: Federal Aviation Administration - NTSB case key (mKey): 73646 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR09CA193 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/73646/pdf - Page: https://openairdocs.org/ntsb/WPR09CA193 ## Probable cause The pilot's encounter with a windshear/downdraft that exceeded the climb performance capabilities of the airplane. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Temp/humidity/pressure: high density altitude](https://openairdocs.org/ntsb-findings/03031020): Environmental issues › Conditions/weather/phenomena · Effect on operation; cases with it: [Piper PA-28-140, 12 cases](https://openairdocs.org/ntsb-findings/03031020/cases.md?model=7102802), [All aircraft, 278 cases](https://openairdocs.org/ntsb-findings/03031020/cases.md) - [Aircraft capability: climb capability](https://openairdocs.org/ntsb-findings/01061010): Aircraft › Aircraft oper/perf/capability · Capability exceeded (probable cause); cases with it: [Piper PA-28-140, 7 cases](https://openairdocs.org/ntsb-findings/01061010/cases.md?model=7102802), [All aircraft, 183 cases](https://openairdocs.org/ntsb-findings/01061010/cases.md) - [Wind: downdraft](https://openairdocs.org/ntsb-findings/03034035): Environmental issues › Conditions/weather/phenomena · Effect on operation (probable cause); cases with it: [Piper PA-28-140, 3 cases](https://openairdocs.org/ntsb-findings/03034035/cases.md?model=7102802), [All aircraft, 178 cases](https://openairdocs.org/ntsb-findings/03034035/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute: Windshear or thunderstorm](https://openairdocs.org/ntsb-events/390) (defining event); cases with it: [Piper PA-28-140, 3 cases](https://openairdocs.org/ntsb-events/390/sequence.md?model=7102802), [All aircraft, 224 cases](https://openairdocs.org/ntsb-events/390/sequence.md) - [Enroute: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Piper PA-28-140, 137 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=7102802), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The pilot was following a highway to the northwest at 10,000 feet mean sea level. He crossed the mountain pass between 700 and 1,000 feet above ground level climbing slowly. Once on the west side of the pass, approaching the base of some cliffs, they encountered a strong down draft and the airspeed dropped rapidly and the airplane started to descend. The pilot reports that he attempted to keep the airspeed at 85 knots and climb but, that the airplane continued to lose altitude. He checked the engine instruments and did not note any degradation of engine performance. The airplane continued to descend. The pilot executed a forced landing in approximately the center of the valley ahead of them. The pilot reported that there were no preimpact mechanical malfunctions or failures. Based on the temperature and pressure readings from the closest weather reporting station, the density altitude at the accident site was about 9,200 feet. ## Factual narrative **Modified on July 2, 2009** On April 13, 2008, at 1510 mountain daylight time, a Piper PA-28-140, N945RH, collided with mountainous terrain 26 miles northwest of Dubois, Wyoming. The private pilot operated the airplane under the provisions of Title 14 Code of Federal Regulations, Part 91. The pilot and passenger received minor injuries, and the airplane was substantially damaged. Visual meteorological conditions prevailed, and a VFR flight plan had been filed. The flight originated at Douglas, Wyoming, at 1300. The pilot reported that he was following Highway 287 to the northwest at 10,000 feet mean sea level (msl). He crossed the Togwatee Pass between 700 and 1,000 feet above ground level (agl), and climbing slowly. Once on the west side of the pass, approaching the base of some cliffs, they encountered a strong down draft and the air speed dropped rapidly and the airplane started to descend. The pilot attempted to keep the airspeed at 85 knots and climb but the airplane continued to lose altitude. He checked the engine instruments and did not note any degradation of engine performance. The airplane continued to descend. The pilot executed a forced landing in approximately the center of the valley ahead of them. The pilot and his passenger broke out a window and egressed the airplane. They hiked to the top of the nearest ridge and called for assistance using a cell phone. The nearest automatic weather observation facility was Jackson Hole Airport, Jackson, Wyoming, which is located 39 miles southwest of the accident location. At 1457, the winds at Jackson Hole were 170 degrees at 18 knots. ## Aircraft - Registration: [N945RH](https://openairdocs.org/deregistered/N945RH-2013-07-11), registration cancelled 2013-07-11, S/N 28-7225283, built 1972 (OpenAirDocs) - Reported make and model: PIPER PA-28-140 - Registry model: [Piper PA-28-140](https://openairdocs.org/model/piper-pa-28-140) (registry code 7102802) (OpenAirDocs) - Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 28-7225283 - Airframe hours: 6052 - Engines: Lycoming O-320-E2A 150 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Donald S. Ballard - Registered owner: Donald S. Ballard - Airworthiness certificate: Standard, Normal - Last inspection: Annual, August 1, 2008 - Departed: KDGW, Converse County, WY - Destination: KIDA, Idaho falls, ID - Flight plan: VFR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 32; injuries: minor; private; airplane ratings: single-engine land; medical: class 3, without waivers/limitations; last flight review May 9, 2008; seat: left; flight hours: 120 total, 21 in this make and model, 80 as pilot in command ## Weather - Conditions: Visual (VMC), Day - Wind: 170° at 18 knots - Visibility: 10 statute miles - Temperature: 45 °F, dew point 27 °F - Altimeter: 29.95 inHg - Observed at: KJAC, 39 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 20090413004869A](https://openairdocs.org/incident/20090413004869A), Apr 13, 2009: Piper PA28140, Dubois, WY, Substantial damage. (-23) Aircraft encountered down draft and pilot could not maintain altitude to clear terrain. 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.