# NTSB ANC23LA063: Cessna U206G, N4891Z, Skwentna, AK, August 14, 2023 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 4 · Limited · Final report - Date: August 14, 2023, 10:20 local (18:20 UTC) - Place: Skwentna, AK - Coordinates: 61.953016, -151.25359 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=61.9530&lon=-151.2536&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing: Collision during takeoff/land](https://openairdocs.org/ntsb-events/490) - Highest injury: No injuries - Injuries: 5 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 4 - Basic report with no Prelim publish - NTSB office: Alaska Regional Office - Parties: FAA - NTSB case key (mKey): 192889 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC23LA063 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/192889/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=192889 - Page: https://openairdocs.org/ntsb/ANC23LA063 ## Probable cause The airplane’s float contacted an undetected submerged gravel bar during landing which resulted in a nose over. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Runway/land/takeoff/taxi surface](https://openairdocs.org/ntsb-findings/03023000): Environmental issues › Physical environment · Contributed to outcome (probable cause); cases with it: [Cessna U206G, 2 cases](https://openairdocs.org/ntsb-findings/03023000/cases.md?model=2073356), [All aircraft, 253 cases](https://openairdocs.org/ntsb-findings/03023000/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 U206G, 13 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=2073356), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) - [Runway/land/takeoff/taxi surface](https://openairdocs.org/ntsb-findings/03023000): Environmental issues › Physical environment · Awareness of condition (probable cause); cases with it: [Cessna U206G, 2 cases](https://openairdocs.org/ntsb-findings/03023000/cases.md?model=2073356), [All aircraft, 253 cases](https://openairdocs.org/ntsb-findings/03023000/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Landing: Collision during takeoff/land](https://openairdocs.org/ntsb-events/490) (defining event); cases with it: [Cessna U206G, 7 cases](https://openairdocs.org/ntsb-events/490/sequence.md?model=2073356), [All aircraft, 1,309 cases](https://openairdocs.org/ntsb-events/490/sequence.md) - [Landing: Nose over/nose down](https://openairdocs.org/ntsb-events/096); cases with it: [Cessna U206G, 9 cases](https://openairdocs.org/ntsb-events/096/sequence.md?model=2073356), [All aircraft, 2,287 cases](https://openairdocs.org/ntsb-events/096/sequence.md) ## Analysis While landing on a river and coming off the float step, the airplane’s float contacted an undetected submerged gravel bar in shallow water. The airplane pivoted, nosed over, and came to rest inverted. The airplane sustained substantial damage to the vertical stabilizer and rudder. The pilot reported that there were no preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operation. ## Aircraft - Registration: [N4891Z](https://openairdocs.org/aircraft/N4891Z), registered now, S/N U20606044, built 1980 (OpenAirDocs) - Reported make and model: CESSNA U206G - Registry model: [Cessna U206G](https://openairdocs.org/model/cessna-u206g) (registry code 2073356) (OpenAirDocs) - Registry engine: [Continental IO-520 series](https://openairdocs.org/engine/continental-io-520-series) (registry code 17032, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: U20606044 - Year built: 1980 - Airframe hours: 18019 - Engines: Continental IO-520-F 300 horsepower reciprocating - Damage: Substantial damage - Flight: Business, Part 135 - Operator: Rust's Flying Service, doing business as Rust's Flying Service - Registered owner: Rustair Inc - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, August 3, 2023 - Departed: PALH, Anchorage, AK - Destination: Same as departure - Flight plan: Company VFR - Airport: NA - Equipment: Stall warning system, ADS-B, Handheld GPS, Satellite tracking device ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 66; injuries: none; airline transport, flight instructor, commercial, flight engineer; airplane ratings: single-engine land, single-engine sea, multi-engine land; instrument ratings: helicopter; medical: class 1, with waivers/limitations; seat: left; restraint: 3-point; flight hours: 17,653 total, 500 in this make and model, 9,553 as pilot in command, 253 in the last 90 days, 107 in the last 30 days, 6 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Lowest ceiling: 4,000 ft overcast - Temperature: 58 °F - Altimeter: 29.88 inHg ## 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 20230814008799A](https://openairdocs.org/incident/20230814008799A), Aug 14, 2023: Cessna U206G, Skwentna, AK, Substantial damage. Pilot attempted a landing in the yentna river near the mouth of fish creek heading upstream close to mid-day. The left float impacted a submerged sand / gravel… ## Docket (2 files) The files NTSB released with the investigation on October 26, 2023, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=192889. 5.4 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 9 pages, 5.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16030036&FileExtension=pdf&FileName=NTSB%20Form%206120.1%20N4891Z%208.14.23_Redacted-Rel.pdf - Investigation photograph (item 2, PDF, 2 pages, 278 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16029769&FileExtension=pdf&FileName=Photo%20Array-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.