# NTSB WPR23LA305: Grumman Acft ENG Cor-Schweizer G-164A, N5450, Davis, CA, August 6, 2023 - Type: NTSB accident investigation - Classification: Accident · Fatal · Class 3 · Limited · Final report - Date: August 6, 2023, 09:27 local (16:27 UTC) - Place: Davis, CA - Coordinates: 38.516972, -121.67063 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=38.5170&lon=-121.6706&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering-low-alt flying: Loss of control in flight](https://openairdocs.org/ntsb-events/240) - Highest injury: Fatal - Injuries: 1 fatal - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Western Pacific Region - Parties: FAA - SAIBs cited in the narratives: [SAIB CE-09-35](https://openairdocs.org/saib/CE-09-35) (OpenAirDocs) - NTSB case key (mKey): 192817 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR23LA305 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/192817/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=192817 - Page: https://openairdocs.org/ntsb/WPR23LA305 ## Probable cause An inflight loss of control during a low altitude operation for undetermined reasons. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Grumman Acft ENG Cor-Schweizer G-164A, 10 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=3952801), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/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: Loss of control in flight](https://openairdocs.org/ntsb-events/240) (defining event); cases with it: [Grumman Acft ENG Cor-Schweizer G-164A, 6 cases](https://openairdocs.org/ntsb-events/240/sequence.md?model=3952801), [All aircraft, 5,002 cases](https://openairdocs.org/ntsb-events/240/sequence.md) - [Maneuvering-low-alt flying: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Grumman Acft ENG Cor-Schweizer G-164A, 20 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=3952801), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The pilot was flying an aerial application flight over a tomato field from west to east when the airplane impacted a field and was consumed by a postimpact fire. There were no witnesses to the accident. Postaccident examination of the airplane revealed substantial impact and thermal damage to the airframe and its corresponding systems. Impact signatures on the propeller revealed leading edge gouges, chordwise scratches on the face side of one propeller blade, and aft bending on both propeller blades in the opposite direction of rotation, which is consistent with some rotation at the time of impact. The propeller exhibited some indication of power at the time of impact; however, the impact and thermal damage prevented a determination to what extent the engine was operating at the time of the accident. ## Factual narrative The operator identified the insecticide used in the aerial application as Wilbur-Ellis BEN-SUL 85. According to the United States Environmental Protection Agency, Pesticide Product Label, the pesticide contained 85 percent Sulfur and is marked with a label stating, “CAUTION: Harmful if absorbed through the skin. Causes eye irritation. Avoid contact with skin, eyes or clothing.” Additionally, the operator reported that the accident airplane was solely used to conduct aerial applications of Wilbur-Ellis BEN-SUL 85. The operator provided airframe, engine, and propeller logbooks from the last annual inspection, which was less than one month before the accident, on July 31, 2023. No additional logbook entries were provided. On August 06, 2023, about 0927 Pacific daylight time, a Grumman G164A, N5450, sustained substantial damage when it was involved in an accident near Davis, California. The pilot sustained fatal injuries. The airplane was operated as Title 14 Code of Federal Regulations Part 137 aerial application flight. The purpose of the flight was for the pilot to conduct an aerial application of pesticide on a local tomato crop. According to the operator, the airplane was topped off with fuel and 1,700 lbs of pesticide the night before the accident. The morning of the accident, the pilot departed from Medlock Field Airport (69CL), Woodland, California, and conducted aerial applications while flying from west to east about 68 ft agl. An employee responsible for refueling the airplane and loading the hopper reported that the airplane was fueled to about ¾ of a full tank and he added 1,500 lbs of pesticide before the accident. The employee reported that he continued with their daily tasks and did not witness the accident. There were no witnesses to the accident. Postaccident examination of the ground scars and the resting position of the airplane revealed that the airplane landed on the soft-field and nosed over. A fire consumed the airplane wreckage; the operator reported that the pilot self-extricated and was transported to a nearby medical facility. An autopsy of the pilot was performed by the Sacramento County Department of the Coroner. According to the pilot’s autopsy report, the cause of death was complications associated with thermal injuries. The pilot succumbed to his injuries 25 days after the accident. The weather reported at an airport about 12 nautical miles from the accident site included a temperature of 82°F and a dew point 59°F. The calculated relative humidity at this temperature and dewpoint was 46 percent. Review of the icing probability chart contained within Federal Aviation Administration Special Airworthiness Information Bulletin CE-09-35 revealed the atmospheric conditions at the time of the accident were conducive to serious icing at glide power. No pilot logbooks were recovered or provided during this investigation. Review of photographic evidence revealed that ground scars, consistent with the landing, were about 93 fteast of the main wreckage. The wreckage came to rest, inverted in the field where the pilot was applying pesticide. A fire consumed the engine compartment, fuselage, and empennage. Examination of the airplane revealed substantial impact and thermal damage; due to the damage the investigation was not able to identify the source of the fire or determine if it began in flight. The left and right upper and lower wings sustained impact damage to the leading edges, with thermal damage signatures emanating from the wing roots. The engine was separated from the engine mount and came to rest about 4 ft from the main wreckage. Examination of the recovered wreckage revealed that the cockpit was mostly consumed by fire except for the steel tube frame, which was thermally damaged, but remained intact. Flight control continuity was observed. The fuel system was completely consumed by fire. Examination of the airplane’s engine showed that it was separated from the airframe; however, it remained attached to engine mount structure. No holes were observed in the engine cases. All nine cylinders remained attached and secured to the intermediate case. The rear case and engine accessories exhibited thermal damage. Damage to the magneto prevented a functional test. The carburetor, generator, and remains of the magneto were removed from the rear case and the front spark plugs were removed from each cylinder. The propeller was rotated by hand throughout 360°. Rotational continuity was established throughout the engine and valvetrain, with movement observed on all the rear accessory case gears. Thumb compression was obtained on all cylinders except for cylinder Nos. 5 and 9. Each cylinder was examined internally using a lighted borescope. Varying degrees of corrosion, water, oil, and dirt were observed in each cylinder. All intake and exhaust valves, pistons, and internal areas of each cylinder were unremarkable except for cylinder Nos. 5 and 9, in which the intake and exhaust seats exhibited an abundance of dirt debris. All front spark plugs exhibited normal operation signatures. The oil screen contained a small amount of melted metallic debris. A visual examination of the carburetor revealed impact and thermal damage. The throttle and mixture control ends remained attached to their respective controls on the carburetor. The jet covers were removed and both metering jets were found secure. The carburetor could not be disassembled due to impact damage. ## Aircraft - Registration: [N5450](https://openairdocs.org/aircraft/N5450), registered now, S/N 1160 (OpenAirDocs) - Reported make and model: GRUMMAN ACFT ENG COR-SCHWEIZER G-164A - Registry model: [Grumman Acft ENG Cor-Schweizer G-164A](https://openairdocs.org/model/grumman-acft-eng-cor-schweizer-g-164a) (registry code 3952801) (OpenAirDocs) - Registry engine: [Pratt & Whitney R1340 series](https://openairdocs.org/engine/pratt-whitney-r1340-series) (registry code 52016, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 1160 - Year built: 1973 - Airframe hours: 13921.53 - Engines: P&W R-1340-AN-1 600 horsepower reciprocating - Damage: Substantial damage - Fire: Fire at unknown time - Flight: Aerial application, Part 137 - Operator: Growers Air Service - Registered owner: Growers Air Service - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Annual, July 21, 2023 - Departed: 69CL, Woodland, CA - Equipment: Satellite tracking device ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 55; injuries: fatal; commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; seat: single; flight hours: 15,538 total, 0 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 82 °F, dew point 59 °F - Altimeter: 29.97 inHg - Observed at: KVCB, 12 nm away - METAR: KVCB 061553Z AUTO 00000KT 10SM CLR 28/15 A2997 RMK AO2 SLP147 T02780150 ## 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 20230806013489A](https://openairdocs.org/incident/20230806013489A), Aug 6, 2023: Grumman Acft Eng Cor-Schweizer G-164A, Davis, CA, Substantial damage, 1 fatal. On August 6th, 2023, the pilot ws dusting field when he reported that the engine failed while making a pass at approximately 50' AGL. Aircraft contacted the… ## Other investigations on N5450 (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 LAX95LA126](https://openairdocs.org/ntsb/LAX95LA126), Mar 4, 1995: Schweizer G-164A (N5450), Robbins, CA, substantial damage. Probable cause: A failure of the engine master rod. A factor in the accident was the soft, wet condition of the field available for the forced landing. ## Docket (13 files) The files NTSB released with the investigation on July 24, 2025, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=192817. 223 MB in all. - Record of conversation -operator (item 1, PDF, 1 page, 68 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18891604&FileExtension=pdf&FileName=Memorandum%20for%20Record%20-Operator-Rel.pdf - Record of conversation -hernandez (item 2, PDF, 1 page, 67 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18892242&FileExtension=pdf&FileName=Memorandum%20for%20Record%20-Hernandez-Rel.pdf - Record of conversation -lara (item 3, PDF, 1 page, 66 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18892116&FileExtension=pdf&FileName=Memorandum%20for%20Record%20-Lara-Rel.pdf - Record of conversation -inspector beck -social media post (item 4, PDF, 1 page, 269 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18891750&FileExtension=pdf&FileName=Memorandum%20for%20Record%20-Social%20Media%20Post-Rel.pdf - Record of conversation -yolo county sheriff's office (item 5, PDF, 2 pages, 71 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18912016&FileExtension=pdf&FileName=Memorandum%20for%20Record%20-LEA-Rel.pdf - FAA inspector beck -wilbur-ellis ben-sul 85 (item 6, PDF, 1 page, 259 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18892346&FileExtension=pdf&FileName=Inspector%20Beck%20-Growers%20Air%20Services%20Operations_Redacted-Rel.pdf - United states environmental protection agency -wilbur-ellis ben-sul 85 (item 7, PDF, 5 pages, 669 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18892530&FileExtension=pdf&FileName=EPA%20-Willis-Ellis%20BEN-SUL%2085_Redacted-Rel.pdf - Maintenance log excerpts (item 8, PDF, 13 pages, 218 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18892431&FileExtension=pdf&FileName=Logbooks_Redacted-Rel.pdf - FAA forensic toxicology report (item 9, PDF, 1 page, 231 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18891857&FileExtension=pdf&FileName=FAA%20Forensic%20Toxicology%20Report_Redacted-Rel.pdf - Record of conversation -NTSB fire and explosion specialist (item 10, PDF, 1 page, 67 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18891760&FileExtension=pdf&FileName=Memorandum%20for%20Record%20-McAtee-Rel.pdf - Investigation photographs (item 11, PDF, 6 pages, 1.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18891584&FileExtension=pdf&FileName=Photographs-Rel.pdf - Examination summary (item 12, PDF, 3 pages, 155 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18909943&FileExtension=pdf&FileName=N5450%20Examination%20Report-Rel.pdf - Examination photographs (item 13, PDF, 8 pages, 1.9 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18892540&FileExtension=pdf&FileName=Examination%20Photographs-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.