# NTSB WPR22LA293: Air Tractor AT-301, N36542, Circle, MT, August 7, 2022 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 4 · Limited · Final report - Date: August 7, 2022, 08:49 local (14:49 UTC) - Place: Circle, MT - Coordinates: 47.369685, -105.44059 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=47.3697&lon=-105.4406&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering-low-alt flying: Fuel related](https://openairdocs.org/ntsb-events/190) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 4 - Basic report with no Prelim publish - NTSB office: Western Pacific Region - Parties: Federal Aviation Administration - NTSB case key (mKey): 105693 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR22LA293 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/105693/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=105693 - Page: https://openairdocs.org/ntsb/WPR22LA293 ## Probable cause The loss of engine power due to carburetor ice. Contributing to the accident was the pilot’s failure to use carburetor heat. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Engine fuel and control: fuel control/carburetor](https://openairdocs.org/ntsb-findings/01057322): Aircraft › Aircraft power plant · Not specified (probable cause) - [Temp/humidity/pressure: conducive to carburetor icing](https://openairdocs.org/ntsb-findings/03031030): Environmental issues › Conditions/weather/phenomena · Contributed to outcome (probable cause) - [Action: lack of action](https://openairdocs.org/ntsb-findings/02041030): Personnel issues › Action/decision · Pilot (probable cause) ## Analysis The pilot reported that, following an aerial application on field, he was returning to a private [air]strip, when the engine began to run rough and lost power at an altitude of about 100 ft above ground level. The pilot initiated a forced landing to a wheat field, however, the airplane impacted terrain about 75 ft short of the field, which resulted in substantial damage to the fuselage. The pilot reported that there were no preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operation. The pilot added that carburetor ice “was not even considered at the time of power loss” and that the conditions favorable to carburetor ice were not taken into account. Carburetor heat was not used. Weather conditions reported at the time of the accident were conducive for serious carburetor icing at cruise power. ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering-low-alt flying: Fuel related](https://openairdocs.org/ntsb-events/190) (defining event) - [Maneuvering-low-alt flying: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) ## Aircraft - Registration: [N36542](https://openairdocs.org/aircraft/N36542), registered now, S/N 301-0310, built 1980 (OpenAirDocs) - Reported make and model: AIR TRACTOR INC AT-301 - Registry model: [Air Tractor AT-301](https://openairdocs.org/model/air-tractor-at-301) (registry code 0390103) (OpenAirDocs) - Registry engine: [Pratt & Whitney R1340 series](https://openairdocs.org/engine/pratt-whitney-r1340-series) (registry code 52016, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 301-0310 - Year built: 1980 - Airframe hours: 10421 - Engines: P&W R1340 AN-1 600 horsepower reciprocating - Damage: Substantial damage - Flight: Aerial application, Part 137 - Operator: Harris Spraying Inc - Registered owner: Harris Spraying Inc - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Annual, March 29, 2021, 899 hours before ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 80; injuries: minor; commercial; airplane ratings: single-engine land; medical: class 2, with waivers/limitations; last flight review August 21, 2020; seat: center; restraint: 3-point; flight hours: 8,101 total, 4,667 in this make and model, 8,101 as pilot in command, 47 in the last 90 days, 15 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 150° at 3 knots - Lowest ceiling: 4,400 ft overcast - Temperature: 57 °F, dew point 54 °F - Altimeter: 30.16 inHg - Observed at: KGDV, 30 nm away - METAR: KGDV 071456Z AUTO 15003KT FEW010 OVC044 14/12 A3016 RMK AO2 SLP213 T01440122 51008 PWINO $ ## 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 20220807007869A](https://openairdocs.org/incident/20220807007869A), Aug 7, 2022: Air Tractor Inc AT-301, Circle, MT, Substantial damage. On August 17, 2022 at 0849 MST, an Air tractor AT-301, N36542, [privacy data omitted] lost power and impacted the ground while on a CFR part 137 agricultural… ## Docket (4 files) The files NTSB released with the investigation on November 10, 2022, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=105693. 1.6 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 9 pages, 1.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=14590172&FileExtension=pdf&FileName=6120_Redacted-Rel.pdf - Record of conversation - son of the pilot (item 2, PDF, 1 page, 121 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=14590425&FileExtension=pdf&FileName=Record%20of%20Conversation%20son%20of%20pilot-Rel.pdf - FAA special airworthiness information bulletin - carburetor icing prevention (item 3, PDF, 3 pages, 106 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=14590095&FileExtension=pdf&FileName=r_CE-09-35-Rel.pdf - Photo array (item 4, PDF, 1 page, 1 photo, 326 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=14590644&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.