# NTSB CEN22LA354: Air Tractor AT-301, N4326S, Lamoni, IA, August 1, 2022 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: August 1, 2022, 14:20 local (19:20 UTC) - Place: Lamoni, IA - Coordinates: 40.6237, -93.93814 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=40.6237&lon=-93.9381&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering-low-alt flying: Unknown or undetermined](https://openairdocs.org/ntsb-events/000) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Central Region - Parties: Federal Aviation Administration; Des Moines FSDO - NTSB case key (mKey): 105649 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN22LA354 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/105649/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=105649 - Page: https://openairdocs.org/ntsb/CEN22LA354 ## Probable cause A loss of airplane performance for reasons that could not be determined. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Not determined](https://openairdocs.org/ntsb-findings/05000000): Not determined › Not determined · Unknown/Not determined (probable cause); cases with it: [Air Tractor AT-301, 11 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md?model=0390103), [All aircraft, 2,247 cases](https://openairdocs.org/ntsb-findings/05000000/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: Unknown or undetermined](https://openairdocs.org/ntsb-events/000) (defining event); cases with it: [Air Tractor AT-301, 2 cases](https://openairdocs.org/ntsb-events/000/sequence.md?model=0390103), [All aircraft, 1,703 cases](https://openairdocs.org/ntsb-events/000/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: Attempted remediation/recovery](https://openairdocs.org/ntsb-events/060); cases with it: [Air Tractor AT-301, 2 cases](https://openairdocs.org/ntsb-events/060/sequence.md?model=0390103), [All aircraft, 1,422 cases](https://openairdocs.org/ntsb-events/060/sequence.md) - [Emergency descent: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Air Tractor AT-301, 25 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=0390103), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The pilot stated that the accident flight was the sixth or seventh aerial application flight that he performed on the day of the accident. He stated that the run-up and takeoff for flight were normal. When he turned toward the intended field of application, he “noticed a lack of performance.” The pilot attempted to restore airplane performance without success. He dumped the load of aerial applicant, and airplane then impacted trees and terrain. The airplane was destroyed by impact forces and postcrash fire. The pilot stated that at the time of the accident the engine instrument indications, which included engine power and propeller speed. A postaccident examination of the engine revealed no mechanical anomalies that would have precluded normal operation, and the reason for the airplane’s reported lack of performance was not determined. ## Factual narrative On August 1, 2022, at 1420 central daylight time, an Air Tractor Inc AT-301, N4326S, was destroyed when it was involved in an accident near Lamoni, Iowa. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 137 aerial application flight. The pilot stated that the accident flight was the sixth or seventh aerial application flight that he performed on the day of the accident. He stated that the run-up and takeoff for the flight were normal. After takeoff, he turned west toward the field and noticed a lack of performance. The pilot turned the airplane toward the north and lowered the airplane’s nose to gain airspeed. He adjusted the propeller, engine power, and flaps, but was unable to maintain altitude. The pilot dumped the load of aerial applicant, and airplane then impacted trees and terrain. The airplane was destroyed by impact forces and postcrash fire. The pilot stated that all engine instrument indications were normal, the engine speed was 2,250 rpm, and the manifold pressure was 37 inches at the time of impact, Postaccident examination of the engine revealed that the rear accessory housing, and all attached accessories, sustained impact and post-crash fire damage. Examination of the engine drive gears leading into the accessory drive housing were found intact and did not display failure. The impeller housing and impeller shaft seal did not display failure. There was no evidence of oil leakage into the impeller housing. Drive gears from the engine into and including the impeller drive did not display failure. There was no abnormal play of the impeller shaft and its bearing. Rotation of the crankshaft drivetrain confirmed continuity. The cylinders exhibited normal features with no corrosion, scoring, or excessive wear. ## Aircraft - Registration: [N4326S](https://openairdocs.org/aircraft/N4326S), registered now, S/N 301-0006 (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 R-985 series](https://openairdocs.org/engine/pratt-whitney-r-985-series) (registry code 52008, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 301-0006 - Year built: 1974 - Airframe hours: 10958 - Engines: Pratt&Whitney R-1340 S3H1G 650 hp reciprocating - Damage: Destroyed - Flight: Aerial application, Part 137 - Operator: Stardust Ag Aviation - Registered owner: Marlow Aviation LLC - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Annual, May 1, 2022 - Departed: LWD, Lamoni, IA - Destination: Same as departure - Airport: LWD, Lamoni Municipal Airport ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 38; injuries: minor; commercial, airline transport; airplane ratings: multi-engine land, single-engine sea, single-engine land; instrument ratings: airplane; medical: class 2, without waivers/limitations; last flight review October 9, 2021; seat: single; restraint: 4-point; flight hours: 5,400 total, 810 in this make and model, 4,794 as pilot in command, 311 in the last 90 days, 156 in the last 30 days, 7 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 340° at 3 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 81 °F, dew point 68 °F - Altimeter: 29.98 inHg - Observed at: KLWN ## 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 20220801007619A](https://openairdocs.org/incident/20220801007619A), Aug 1, 2022: Air Tractor Inc AT-301, Leon, IA, Destroyed. Pilot experienced lack of engine performance for unknown reasons while enroute to the field to be sprayed. The aircraft impacted a heavy wooded area causing a… ## Other investigations on N4326S (3) 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 SEA98LA079](https://openairdocs.org/ntsb/SEA98LA079), May 19, 1998: Air Tractor AT-301 (N4326S), Idaho Falls, ID, substantial damage. Probable cause: The pilot's inadequate inflight decision to land with a tailwind and his failure to maintain aircraft control. Also contributing was the pilot's improper setting of the fuel mixture which resulted in… - [NTSB SEA95LA154](https://openairdocs.org/ntsb/SEA95LA154), Jul 17, 1995: Air Tractor AT-301 (N4326S), Roberts, ID, substantial damage. Probable cause: A LOSS OF ENGINE POWER DUE TO THE SEPARATION OF THE NUMBER 3 CYLINDER EXHAUST VALVE ROCKER ARM SHAFT FROM THE CYLINDER HEAD, WHICH DISABLED MOVEMENT OF THE EXHAUST VALVE. A FACTOR WAS THE LACK OF… - [NTSB LAX82DA265](https://openairdocs.org/ntsb/LAX82DA265), Jul 18, 1982: Air Tractor AT-301 (N4326S), San Joaquin, CA, substantial damage ## Docket (3 files) The files NTSB released with the investigation on April 25, 2024, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=105649. 9.5 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 9 pages, 8.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15902297&FileExtension=pdf&FileName=6120%20Master_Redacted-Rel.pdf - FAA inspector's examination statement (item 2, PDF, 1 page, 153 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15911583&FileExtension=pdf&FileName=FAA%20Inspector%20Statement%20Mastr_Redacted-Rel.pdf - Photo log (item 3, PDF, 1 page, 1.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15919058&FileExtension=pdf&FileName=Photos-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.