# NTSB WPR20LA203: Cessna 172, N6929H, Alpine, UT, July 3, 2020 - Type: NTSB accident investigation - Classification: Accident · Fatal · Class 3 · Limited · Final report - Date: July 3, 2020, 07:22 local (13:22 UTC) - Place: Alpine, UT - Coordinates: 40.499168, -111.658058 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=40.4992&lon=-111.6581&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute-cruise: Loss of control in flight](https://openairdocs.org/ntsb-events/240) - Highest injury: Fatal - Injuries: 4 fatal - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Western Pacific Region - Parties: Textron, FAA, Lycoming - NTSB case key (mKey): 101529 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR20LA203 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/101529/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=101529 - Page: https://openairdocs.org/ntsb/WPR20LA203 ## Probable cause The pilot’s exceedance of the airplane’s critical angle-of-attack while maneuvering in a canyon, which resulted in a loss of airplane control. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Performance/control parameters: angle of attack](https://openairdocs.org/ntsb-findings/01062042): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Cessna 172M, 4 cases](https://openairdocs.org/ntsb-findings/01062042/cases.md?model=2072418), [All aircraft, 990 cases](https://openairdocs.org/ntsb-findings/01062042/cases.md) - [Info processing/decision: decision making/judgment](https://openairdocs.org/ntsb-findings/02041520): Personnel issues › Action/decision · Pilot (probable cause); cases with it: [Cessna 172M, 36 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md?model=2072418), [All aircraft, 3,098 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md) - [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Cessna 172M, 123 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=2072418), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) - [Terrain: mountainous/hilly terrain](https://openairdocs.org/ntsb-findings/03021010): Environmental issues › Physical environment · Effect on operation; cases with it: [Cessna 172M, 7 cases](https://openairdocs.org/ntsb-findings/03021010/cases.md?model=2072418), [All aircraft, 329 cases](https://openairdocs.org/ntsb-findings/03021010/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute-cruise: Loss of control in flight](https://openairdocs.org/ntsb-events/240) (defining event); cases with it: [Cessna 172M, 47 cases](https://openairdocs.org/ntsb-events/240/sequence.md?model=2072418), [All aircraft, 5,002 cases](https://openairdocs.org/ntsb-events/240/sequence.md) ## Analysis The pilot and three passengers departed the airport for a daytime personal flight in favorable weather conditions. Radar data indicated the airplane flew on a southbound heading for about 25 minutes, steadily climbing to an altitude of 6,200 feet, before turning to the northeast and flying over a lake. The airplane continued on a north/northeast heading and climbed to an altitude of 8,785 feet over the next 16 minutes. It disappeared off radar 4 minutes later after performing a 270º turn in a canyon. A witness in the area observed the airplane approach the canyon headed in a northwest direction and noted that he thought the airplane was too low to clear the terrain and depart the canyon. He observed the airplane enter a “tight, right banking turn” in the canyon. The airplane leveled off after turning about 180º, followed by a couple of left and right wing-tip oscillations before it entered a clockwise, corkscrew spin and disappeared from view in a vertical, nose-down attitude. The witness reported that the airplane’s engine was producing the same, constant sound until it started to vertically descend, and the noise started to oscillate. Examination of the airplane and engine revealed no preimpact mechanical anomalies, and damage to the crankshaft flange and propeller was consistent with the engine producing power at the time of impact. Additionally, autopsy and toxicology of the pilot did not reveal evidence of physiological impairment or incapacitation. The radar data, witness statement, and damage to the airplane were all consistent with a loss of control after the pilot exceeded the airplane’s critical angle-of-attack while maneuvering in the canyon. ## Factual narrative On July 3, 2020, about 0722 mountain daylight time, a Cessna 172 airplane, N6929H, was destroyed when it was involved in an accident near Alpine, Utah. The pilot and three passengers sustained fatal injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. Radar data revealed that the airplane departed at 0637 from South Valley Regional Airport (U42) Salt Lake City, Utah, on a southerly heading. The airplane continued flying south and climbed to an altitude of about 5,500 feet. About 0642, it made a right 360º turn, then continued flying south, eventually climbing to an altitude of about 6,200 feet, around the western edge of Utah Lake. About 0702, the airplane made a left turn and began flying in a northeast direction, across Utah Lake. The airplane climbed as it crossed the lake and reached an altitude of 7,100 feet as it flew over the eastern edge of the lake. At 0712 and an altitude of approximately 8,000 feet, the airplane made a slight left turn to a northern heading. It continued to climb until it was lost off radar at 0714 at an altitude of 8,250 feet. The airplane reappeared on radar at 0718 at 8,785 feet on a northeast heading. It continued for about another minute and then made a right 270º turn, before disappearing from radar about 0722 on a west/northwest heading, at an altitude of 8,800 feet. A witness located near the accident site observed the airplane approach a canyon headed in a northwest direction. The witness noted that he thought the airplane was too low to clear the terrain and depart the canyon. He observed the airplane enter a “tight, right banking turn” in the canyon. The airplane leveled off after turning about 180º, followed by a couple of left and right wing-tip oscillations before it entered a clockwise, corkscrew spin. The airplane made about 1 1/2 - 2 rotations before it disappeared from the witness's line of sight in a vertical, nose-down attitude. The witness reported that the airplane’s engine was producing the same, constant sound until it started to vertically descend, and the noise started to oscillate. First responders to the accident site reported all components of the airplane were contained within about 100 feet of the main wreckage. Additionally, there was no smell of fuel at the accident site and the wing tanks appeared dry. Hydraulic deformation was observed to both wing tanks. A postaccident examination of the engine revealed the crankshaft was able to freely and easily rotate in both directions. Thumb compression and valve train continuity was confirmed on all four cylinders. The propeller was separated at the crankshaft flange, which exhibited torsional overload signatures consistent with the absorption of rotational energy. Additionally, one of the propeller blades displayed significant leading-edge gouging, torsional twisting, and chordwise striations across the cambered surface, as well as trailing edge “S” bending. No evidence of pre-impactmechanical anomalies was observed. An autopsy was performed on the pilot and front-seat passenger, by the Utah Department of Health, Office of the Medical Examiner. The cause of death for both was blunt force injuries. Toxicology testing was performed on the pilot by the FAA Forensic Sciences Laboratory. The testing was negative for ethanol and other drugs. ## Aircraft - Registration: [N6929H](https://openairdocs.org/deregistered/N6929H-2021-03-30), registration cancelled 2021-03-30, S/N 17265650, built 1975 (OpenAirDocs) - Reported make and model: Cessna 172 (M) - Registry model: [Cessna 172M](https://openairdocs.org/model/cessna-172m) (registry code 2072418) (OpenAirDocs) - Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 17265650 - Year built: 1975 - Engines: Lycoming O-320 SERIES reciprocating - Damage: Destroyed - Flight: Personal, Part 91 - Operator: Tyson Colby Brummett - Registered owner: 6929H Aircraft Leasing LLC - Airworthiness certificate: Standard, Normal - Departed: U42, Salt Lake City, UT - Destination: U42, Salt Lake City, UT - Equipment: Unknown ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 35; injuries: fatal; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, without waivers/limitations; seat: right; restraint: 3-point; toxicology performed; flight hours: 450 total ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 54 °F, dew point 32 °F - Altimeter: 30.21 inHg - Observed at: KHCR ## 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 20200703014429A](https://openairdocs.org/incident/20200703014429A), Jul 3, 2020: Cessna 172M, Alpine, UT, Destroyed, 4 fatal. On 7/3/2020 at 0630 MDT aircraft N6929H a C-172 departed from south valley regional airport (KU42). The plane was piloted by a newly certificated CFI who had… ## Docket (11 files) The files NTSB released with the investigation on June 7, 2022, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=101529. 13.5 MB in all. - Witness statement (item 1, PDF, 1 page, 146 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13242100&FileExtension=pdf&FileName=Gregg%20Rawlings%20(witness)-%20INTERVIEW%20SUMMARY-Rel.pdf - METAR (item 2, PDF, 3 pages, 206 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13237373&FileExtension=pdf&FileName=weather_Redacted-Rel.pdf - Radar video (item 3, MP4, 8.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13237655&FileExtension=mp4&FileName=N6929H-Rel.mp4 - Tabular track (item 4, CSV, 147 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13237349&FileExtension=csv&FileName=N6929H%20track-Rel.csv - Adsb (item 5, KMZ, 140 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13237665&FileExtension=kmz&FileName=N6929H_A935BF_20200703_ADSB_Eval-Rel.kmz - Pd initial statement (item 6, PDF, 1 page, 146 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13241558&FileExtension=pdf&FileName=LEO%20Initial%20report_Redacted-Rel.pdf - Textron airframe exam report (item 7, PDF, 9 pages, 3.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13237445&FileExtension=pdf&FileName=Tech%20Report%2017265650_Redacted-Rel.pdf - Weight and balance (item 8, PDF, 2 pages, 83 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13242090&FileExtension=pdf&FileName=weight%20and%20balance_Redacted-Rel.pdf - Statement of party representatives to NTSB investigation (item 9, PDF, 2 pages, 346 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13912070&FileExtension=pdf&FileName=WPR20LA203%20Party%20Forms_Redacted-Rel.pdf - Release of aircraft wreckage, NTSB form 6120.15 (item 10, PDF, 1 page, 100 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13265570&FileExtension=pdf&FileName=Wreckage%20Release_Redacted-Rel.pdf - Toxicological report (item 11, PDF, 1 page, 339 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13241344&FileExtension=pdf&FileName=Toxicology_Redacted-Rel.pdf 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.