# NTSB WPR09LA085: Air Tractor AT-301, N3170C, Beaver, UT, January 15, 2009 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: January 15, 2009, 08:45 local (15:45 UTC) - Place: Beaver, UT - Coordinates: 38.192222, -112.505554 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=38.1922&lon=-112.5056&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering-low-alt flying: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340) - Highest injury: Minor injuries - Injuries: 1 minor - Status: Completed, report December 29, 2009 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: Federal Aviation Administration - NTSB case key (mKey): 73244 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR09LA085 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/73244/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=73244 - Page: https://openairdocs.org/ntsb/WPR09LA085 ## Probable cause A loss of engine power while maneuvering due to a sheared propeller blade's pitch change link. Contributing to the accident was lack of suitable terrain for the forced landing. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Propeller system: propeller controlling system](https://openairdocs.org/ntsb-findings/01046120): Aircraft › Aircraft propeller/rotor · Failure (probable cause); cases with it: [Air Tractor AT-301, 1 case](https://openairdocs.org/ntsb-findings/01046120/cases.md?model=0390103), [All aircraft, 25 cases](https://openairdocs.org/ntsb-findings/01046120/cases.md) - [Terrain: snowy/icy terrain](https://openairdocs.org/ntsb-findings/03021030): Environmental issues › Physical environment · Contributed to outcome; cases with it: [Air Tractor AT-301, 1 case](https://openairdocs.org/ntsb-findings/03021030/cases.md?model=0390103), [All aircraft, 77 cases](https://openairdocs.org/ntsb-findings/03021030/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: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340) (defining event); cases with it: [Air Tractor AT-301, 5 cases](https://openairdocs.org/ntsb-events/340/sequence.md?model=0390103), [All aircraft, 820 cases](https://openairdocs.org/ntsb-events/340/sequence.md) - [Maneuvering-low-alt flying: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342); cases with it: [Air Tractor AT-301, 9 cases](https://openairdocs.org/ntsb-events/342/sequence.md?model=0390103), [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md) - [Emergency descent: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Air Tractor AT-301, 19 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=0390103), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Landing-landing roll: Nose over/nose down](https://openairdocs.org/ntsb-events/096); cases with it: [Air Tractor AT-301, 6 cases](https://openairdocs.org/ntsb-events/096/sequence.md?model=0390103), [All aircraft, 2,287 cases](https://openairdocs.org/ntsb-events/096/sequence.md) ## Analysis While maneuvering during an aerial application flight, the pilot noted that the engine began to vibrate and lose power. During the forced landing, the airplane nosed over on the snow-covered terrain. The airplane was recovered from the accident site and examined. No internal engine components were found to have malfunctioned. One of the propeller blade's pitch change pins was observed sheared. ## Factual narrative On January 15, 2009, about 0845 mountain standard time, an Air Tractor AT-301, N3170C, operated by Flying B Aviation, LLC, experienced an engine vibration and partial loss of power while maneuvering during an aerial application flight about 10 miles southeast of Beaver, Utah. The pilot made a forced landing on a snow-covered field. During roll out the airplane nosed over, bending a wing and rudder. The commercial certificated pilot sustained a minor injury, and the airplane was substantially damaged. Visual meteorological conditions prevailed at the time, and no flight plan had been filed. The flight was performed under the provisions of 14 Code of Federal Regulations Part 137, and it originated from Beaver about 0830. The pilot verbally reported to the National Transportation Safety Board investigator that, while he was seeding the designated area, the engine started vibrating very badly. The Pratt & Whitney R-1340 engine had been overhauled several times, and he suspected a mechanical malfunction had occurred. The airplane was subsequently recovered from the accident site and examined under Federal Aviation Administration (FAA) supervision. In summary, the FAA inspector reported finding no evidence of internal engine malfunction when the crankshaft was rotated. No contaminating material was observed in the oil, which looked clean. The FAA inspector reported one observation that, in his opinion, may have related to the vibration reported by the pilot. The FAA inspector stated that one of the propeller's pitch change steel pins, which changes the beta angle of the propeller blade, was found sheared in two. No "Aircraft Accident Report" NTSB form 6120.1, was received by the Safety Board from the pilot/operator. ## Aircraft - Registration: [N3170C](https://openairdocs.org/deregistered/N3170C-2010-09-27), registration cancelled 2010-09-27, S/N 301-0591, built 1984 (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: 301-0591 - Engines: P&W R1340 SERIES 600 horsepower reciprocating - Damage: Substantial damage - Flight: Aerial application, Part 137 - Registered owner: Flying B Aviation LLC - Airworthiness certificate: Special, Restricted (Special) - Departed: U52, Beaver, UT - Destination: U52, Beaver, UT ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 36; injuries: minor; flight instructor, commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; seat: single; flight hours: 6,000 total ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 19 °F, dew point 18 °F - Altimeter: 30.42 inHg - Observed at: MLF, 30 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 20090115000059A](https://openairdocs.org/incident/20090115000059A), Jan 15, 2009: Airtrc AT301, Beaver, UT, Substantial damage. While providing 14 CFR part 137 services under contract to the Utah division of wildlife resources (seeding), the aircraft experienced an engine vibration,… ## Docket (2 files) The files NTSB released with the investigation on October 27, 2009, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=73244. 3.8 MB in all. - FAA Report (item 1, .PDF, 3.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40320411&FileExtension=.PDF&FileName=FAA%20Report-Redacted.PDF - Photo of Broken Pitch Change Pin (FAA Photo) (item 2, .PDF, 246 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40320025&FileExtension=.PDF&FileName=Photo%20of%20Broken%20Pitch%20Change%20Pin%20(FAA%20Photo)-Master.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.