# NTSB CEN21LA119: Cessna 172, N4376Q, Silt, CO, January 31, 2021 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Class 3 · Limited · Final report - Date: January 31, 2021, 14:20 local (21:20 UTC) - Place: Silt, CO - Coordinates: 39.5198, -107.6667 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=39.5198&lon=-107.6667&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering-low-alt flying: Low altitude operation/event](https://openairdocs.org/ntsb-events/220) - Highest injury: Serious injuries - Injuries: 3 serious - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Central Region - Parties: FAA, Textron, Lycoming - NTSB case key (mKey): 102580 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN21LA119 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/102580/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=102580 - Page: https://openairdocs.org/ntsb/CEN21LA119 ## Probable cause The pilot’s failure to avoid powerlines while flying at low altitude. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Object/animal/substance: wire](https://openairdocs.org/ntsb-findings/03022032): Environmental issues › Physical environment · Awareness of condition (probable cause); cases with it: [Cessna 172L, 2 cases](https://openairdocs.org/ntsb-findings/03022032/cases.md?model=2072432), [All aircraft, 588 cases](https://openairdocs.org/ntsb-findings/03022032/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 172L, 11 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md?model=2072432), [All aircraft, 3,098 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering-low-alt flying: Low altitude operation/event](https://openairdocs.org/ntsb-events/220) (defining event); cases with it: [Cessna 172L, 1 case](https://openairdocs.org/ntsb-events/220/sequence.md?model=2072432), [All aircraft, 780 cases](https://openairdocs.org/ntsb-events/220/sequence.md) ## Analysis The pilot was conducting a local sightseeing flight when the airplane impacted high-tension transmission wires. The airplane came to rest about 600 ft past the wires, and the upper 2-foot section of the vertical stabilizer and rudder were separated and located about 100 ft from the wires. Postaccident examination revealed no malfunctions or anomalies of the airplane or engine that would have precluded normal operation. The circumstances of the accident are consistent with the pilot’s failure to avoid powerlines while flying at low altitude. ## Factual narrative On January 31, 2021, about 1420 mountain standard time, a Cessna 172, N4376Q, was destroyed when it was involved in an accident near Silt, Colorado. The pilot and two passengers sustained serious injuries. The airplane was operated as a Title 14 Code of Federal Regulations (CFR) Part 91 personal flight. A passenger’s family member reported that the purpose of the flight was to take some friends’ children flying in the local area. The family member stated that, while expecting the airplane to return for landing, he received a call from the mother stating that they had crashed. The main wreckage was located about 3 miles east of the departure airport in an area of rising terrain. The debris field began about 25 ft past a set of high-tension transmission wires and extended about 670 ft. The upper 2 ft of the vertical stabilizer and rudder were located about 75 ft from the beginning of the debris field. The initial ground scar was located about 475 ft past the transmission wires and was identified by a damaged tree and sheet metal consistent with the color of the airplane. The main wreckage came to rest inverted about 600 ft past the wires. A post-accident airframe examination revealed that the lower portion of the vertical stabilizer and rudder remained attached to the fuselage and exhibited damage consistent with an impact with a wire. The vertical stabilizer leading edge was deformed aft in a U-shaped direction with metal polishing and black paint transfer. Flight control continuity was established to the ailerons, elevators, and rudder, and the flaps were found in the retracted position. Internal continuity was established throughout the engine and valve train. All cylinders were examined with a borescope with no anomalies noted. No mechanical anomalies or malfunctions were found that would have precluded normal operation. A cell phone video recording taken by a passenger from inside the airplane showed the airplane flying at low altitude, followed by an upset event and the subsequent impact sequence. The video did not capture a continuous forward view out of the cockpit windows. ## Aircraft - Registration: [N4376Q](https://openairdocs.org/aircraft/N4376Q), registered now, S/N 17260276 (OpenAirDocs) - Reported make and model: CESSNA 172 - Registry model: [Cessna 172L](https://openairdocs.org/model/cessna-172l) (registry code 2072432) (OpenAirDocs) - Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 17260276 - Year built: 1971 - Engines: Lycoming Engines O-320 reciprocating - Damage: Destroyed - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Departed: KRIL, Rifle, CO - Airport: RIL - Equipment: ADS-B, Video recording device ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 49; injuries: serious; private; airplane ratings: single-engine land; medical: class 3, without waivers/limitations; seat: left; toxicology performed ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 28 °F, dew point 10 °F - Altimeter: 30.43 inHg - Observed at: K5SM, 14 nm away - METAR: K5SM 312115Z AUTO 00000KT 10SM CLR M02/M12 A3043 RMK AO2 ## 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 20210131003299A](https://openairdocs.org/incident/20210131003299A), Jan 31, 2021: Cessna 172L, Silt, CO, Destroyed. Aircraft struck power line at around 100 ft off of ground. Struck vertical and sheared 2 feet off of rudder. Aircraft had no controls and crashed . ## Other investigations on N4376Q (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 DEN78DTE44](https://openairdocs.org/ntsb/DEN78DTE44), Apr 2, 1978: Cessna 172L (N4376Q), Falcon, CO, substantial damage ## Docket (7 files) The files NTSB released with the investigation on July 21, 2022, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=102580. 9.3 MB in all. - Exam summary (item 1, PDF, 4 pages, 936 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12505554&FileExtension=pdf&FileName=Exam%20Summary_For%20Docket-Rel.pdf - Photos (item 2, PDF, 4 pages, 3.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12505210&FileExtension=pdf&FileName=Photo%20Array-Rel.pdf - Onboard image recorder - specialist's factual report (item 3, PDF, 5 pages, 380 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12349167&FileExtension=pdf&FileName=Onboard%20Image%20Recorder%20-%20Specialist%27s%20Factual%20Report-Rel.pdf - Electronic recorder devices - specialist's factual report (item 4, PDF, 7 pages, 1.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12349388&FileExtension=pdf&FileName=Electronic%20Recorder%20Devices%20-%20Specialist%27s%20Factual%20Report-Rel.pdf - Attachment 1 to electronic recorder devices - specialist's factual report -- tabular data (item 5, CSV, 17 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12349581&FileExtension=csv&FileName=Attachment%201%20to%20Electronic%20Recorder%20Devices%20-%20Specialist%27s%20Factual%20Report%20--%20Tabular%20Data-Rel.csv - Textron technical report (item 6, PDF, 8 pages, 2.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12505200&FileExtension=pdf&FileName=Tech%20Report%2017260276_Redacted-Rel.pdf - Statement of party representatives to NTSB investigation (item 7, PDF, 15 pages, 445 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12505765&FileExtension=pdf&FileName=Signed%20Party%20Forms_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.