# NTSB CEN24LA119: Zenith Stol CH750, N750WW, Sextonville, WI, February 23, 2024 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Class 3 · Limited · Final report - Date: February 22, 2024, 18:02 local (Feb 23, 2024, 00:02 UTC) - Place: Sextonville, WI - Coordinates: 43.2983, -90.3023 - Nearby events: https://openairdocs.org/map.md?lat=43.2983&lon=-90.3023&mi=10 - Phase of flight: [Unknown](https://openairdocs.org/ntsb-phases/990) (OpenAirDocs' grouping) - Defining event: [Unknown: Unknown or undetermined](https://openairdocs.org/ntsb-events/000) - Highest injury: Serious injuries - Injuries: 1 serious - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Central Region - Parties: FAA - Milwaukee FSDO - NTSB case key (mKey): 193830 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN24LA119 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/193830/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=193830 - Page: https://openairdocs.org/ntsb/CEN24LA119 ## Probable cause A loss of engine power for reasons that could not be determined, followed by a loss of control and subsequent impact with terrain. ## 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: [Baenen Mark S ZENITH CH750 STOL, 1 case](https://openairdocs.org/ntsb-findings/05000000/cases.md?model=056376P), [All aircraft, 2,247 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md) - [Performance/control parameters](https://openairdocs.org/ntsb-findings/01062000): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Baenen Mark S ZENITH CH750 STOL, 1 case](https://openairdocs.org/ntsb-findings/01062000/cases.md?model=056376P), [All aircraft, 1,269 cases](https://openairdocs.org/ntsb-findings/01062000/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Unknown: Unknown or undetermined](https://openairdocs.org/ntsb-events/000) (defining event); cases with it: [Baenen Mark S ZENITH CH750 STOL, 1 case](https://openairdocs.org/ntsb-events/000/sequence.md?model=056376P), [All aircraft, 1,703 cases](https://openairdocs.org/ntsb-events/000/sequence.md) - [Initial climb: Loss of control in flight](https://openairdocs.org/ntsb-events/240); cases with it: [Baenen Mark S ZENITH CH750 STOL, 1 case](https://openairdocs.org/ntsb-events/240/sequence.md?model=056376P), [All aircraft, 5,002 cases](https://openairdocs.org/ntsb-events/240/sequence.md) ## Analysis The pilot reported that he had recently changed the carburetor on the experimental, amateur-built airplane’s engine, and the accident flight was his third flight with the new carburetor. Although the previous flights had been uneventful, he thought that the fuel/air mixture was too rich. He stated that he intended to remain in the airport traffic pattern during the accident flight; however, he had no memory of the events of the flight. A witness reported seeing the airplane as it was departing the airport. The witness reported that the airplane was flying about 60 ft above ground level (agl) and climbed to about 100 ft agl followed by a shallow, descending left turn. The witness did not hear any engine noise and thought that the propeller was not spinning. The witness noted that the airplane was traveling very slow and then dropped straight down. The airplane impacted terrain and came to rest in a field less than 1 mile from the airport. Examination of the airplane, engine, and systems revealed no evidence of any preimpact anomalies that would have precluded normal operation. The propeller blades did not exhibit signs of rotation at the time of impact. The witness, who responded to the accident site, reported that there was an odor of fuel at the site. Based on the available information, it is likely that the engine lost power shortly after takeoff. The witness’ account of the airplane traveling “very slow” and descending “straight down” is consistent with a loss of airplane control. ## Factual narrative On February 22, 2024, at 1802 central standard time, an experimental, amateur-built Zenith CH750 STOL, N750WW, was substantially damaged when it was involved in an accident near Sextonville, Wisconsin. The pilot sustained serious injuries. The airplane was operated as a Title 14 Code of Federal Regulations part 91 personal flight. The pilot reported that he had recently changed the carburetor on the airplane’s engine, and the accident flight was his third flight with the new carburetor. Although the previous flights had been uneventful, he thought that the fuel/air mixture was too rich. He stated that he intended to remain in the traffic pattern during the accident flight; however, he had no memory of the events of the flight. A witness in the area reported seeing the airplane as it was departing Richland Airport (93C), Richland Center, Wisconsin. The witness reported that the airplane was flying about 60 ft agl and climbed to about 100 ft agl followed by a descending, shallow left turn. The witness did not hear any engine noise and thought that the propeller was not spinning. The witness noted that the airplane was traveling very slow and then dropped straight down. At 1802, the witness made a 911 call and rendered aid to the pilot. An odor of fuel was present at the accident site. The airplane came to rest in a field on the edge of a tree line less than 1 mile north of 93C. The airplane came to rest upright with several tree branches lying near the wreckage. The left wing was impact separated. Postaccident examination of the airplane revealed that both wings and the fuselage sustained substantial damage during the accident sequence. One of the two propeller blades remained attached to the propeller hub; the other blade was broken at the propeller hub and located near the wreckage. Both blades were mostly intact and did not exhibit rotational scoring, leading edge damage, or chordwise scratches. There were no preimpact anomalies found with the airframe or the flight controls. The airplane was equipped with an automotive engine that had been modified for use in the airplane. There were two independent ignition systems that functioned properly when external power was applied to the electrical system. Examination of the engine revealed no anomalies that would have precluded normal operation. The airplane’s alternator and voltage regulator were examined and tested. Examination of the alternator revealed that the rotating magnet assembly slipped on the shaft when the drive coupling was rotated by hand. The torque nut was tightened, and the alternator functioned normally. The voltage regulator functioned normally when tested. No anomalies were found with the voltage regulator. ## Aircraft - Registration: [N750WW](https://openairdocs.org/aircraft/N750WW), registered now, S/N 75-10750, built 2019 (OpenAirDocs) - Reported make and model: ZENITH STOL CH750 - Registry model: [Baenen Mark S ZENITH CH750 STOL](https://openairdocs.org/model/baenen-mark-s-zenith-ch750-stol) (registry code 056376P) (OpenAirDocs) - Registry engine: [Amateur-built UNKNOWN ENG](https://openairdocs.org/engine/amateur-built-unknown-eng) (registry code 99999) (OpenAirDocs) - Category: Airplane, amateur-built - Serial number: 75-10750 - Year built: 2019 - Airframe hours: 251.7 - Engines: Corvair 2700cc 100 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: Baenen Mark S - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Condition, March 18, 2023 - Destination: Same as departure - Flight plan: VFR - Airport: 93C, Richland - Equipment: Handheld GPS, Electronic flight bag or handheld device, ADS-B, Onboard weather ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 54; injuries: serious; private; airplane ratings: single-engine land; medical: class 3, with waivers/limitations; last flight review August 26, 2022; seat: left; restraint: 3-point; flight hours: 368 total, 247 in this make and model, 368 as pilot in command, 3 in the last 90 days, 1 in the last 30 days ## Weather - Conditions: Visual (VMC), Dusk - Wind: 300° at 8 knots - Visibility: 10 statute miles - Lowest ceiling: 6,500 ft broken - Temperature: 55 °F, dew point 34 °F - Altimeter: 29.66 inHg - Observed at: KLNR, 7 nm away - METAR: KLNR 222356Z AUTO 30008KT 10SM BKN065 BKN080 13/01 A2966 RMK AO2 SLP044 T01280011 10172 20117 55002 ## 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 20240222002219A](https://openairdocs.org/incident/20240222002219A), Feb 22, 2024: Baenen Mark S ZENITH CH750 STOL, Richland Center, WI, Destroyed. On the evening of February 22, 2024, at approximately 1800 local time, the accident aircraft departed from Richland Airport, sextonville, WI (93C). At some… ## Docket (9 files) The files NTSB released with the investigation on April 23, 2025, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=193830. 4.6 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 9 pages, 1.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17872352&FileExtension=pdf&FileName=NTSB%206120.1%20750WW%203-9-2024_Redacted-Rel.pdf - Investigation photographs (item 2, PDF, 3 pages, 1.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18260352&FileExtension=pdf&FileName=Investigation%20Photographs%20CEN24LA119-Rel.pdf - Examination summary (item 3, PDF, 5 pages, 138 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18515793&FileExtension=pdf&FileName=Exam%20Summary%20N750WW-Rel.pdf - Memorandum for record a�� telephone interview, pilot (item 4, PDF, 1 page, 63 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18260141&FileExtension=pdf&FileName=Record%20of%20Conversation%20-%20Baenen-Rel.pdf - Memorandum for record a�� telephone interview, witness (item 5, PDF, 1 page, 66 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18259164&FileExtension=pdf&FileName=Record%20of%20Conversation%20-%20Kinyon-Rel.pdf - Multiple electronic devices - specialist's factual report (item 6, PDF, 3 pages, 372 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17870168&FileExtension=pdf&FileName=Multiple%20Electronic%20Devices%20-%20Specialist%27s%20Factual%20Report_CEN24LA119-Rel.pdf - Memorandum for record a�� pilot engine exam (item 7, PDF, 1 page, 62 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18260342&FileExtension=pdf&FileName=MOR%20Baenen%20Exam-Rel.pdf - Release of aircraft wreckage, NTSB form 6120.15 (item 8, PDF, 1 page, 513 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18316563&FileExtension=pdf&FileName=Release%20of%20Bulk%20Wreckage%20Form%20N750WW_Page_1_Redacted-Rel.pdf - Release of aircraft wreckage - components (item 9, PDF, 1 page, 518 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18316082&FileExtension=pdf&FileName=Release%20of%20Bulk%20Wreckage%20Alt_VR%20Form%20N750WW_Page_1_Redacted-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.