# NTSB CEN23LA169: Zenith Stol CH750, N750TK, Udall, KS, May 3, 2023 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: May 2, 2023, 20:13 local (May 3, 2023, 01:13 UTC) - Place: Udall, KS - Coordinates: 37.415179, -97.1322 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=37.4152&lon=-97.1322&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing: Collision during takeoff/land](https://openairdocs.org/ntsb-events/490) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Central Region - Parties: FAA Wichita FSDO - NTSB case key (mKey): 107810 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN23LA169 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/107810/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=107810 - Page: https://openairdocs.org/ntsb/CEN23LA169 ## Probable cause The pilot’s failure to maintain clearance from power lines. Contributing to the accident was the reported loss of engine power for reasons that could not be determined. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Attention/monitoring](https://openairdocs.org/ntsb-findings/02021500): Personnel issues › Psychological · Pilot (probable cause); cases with it: [Timothy D Mccall STOL CH 750, 1 case](https://openairdocs.org/ntsb-findings/02021500/cases.md?model=05633EM), [All aircraft, 18 cases](https://openairdocs.org/ntsb-findings/02021500/cases.md) - [Object/animal/substance: wire](https://openairdocs.org/ntsb-findings/03022032): Environmental issues › Physical environment · Response/compensation (probable cause); cases with it: [Timothy D Mccall STOL CH 750, 1 case](https://openairdocs.org/ntsb-findings/03022032/cases.md?model=05633EM), [All aircraft, 588 cases](https://openairdocs.org/ntsb-findings/03022032/cases.md) - [Engine (reciprocating)](https://openairdocs.org/ntsb-findings/01058500): Aircraft › Aircraft power plant · Unknown/Not determined (probable cause); cases with it: [Timothy D Mccall STOL CH 750, 1 case](https://openairdocs.org/ntsb-findings/01058500/cases.md?model=05633EM), [All aircraft, 497 cases](https://openairdocs.org/ntsb-findings/01058500/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute: Unknown or undetermined](https://openairdocs.org/ntsb-events/000); cases with it: [Timothy D Mccall STOL CH 750, 1 case](https://openairdocs.org/ntsb-events/000/sequence.md?model=05633EM), [All aircraft, 1,703 cases](https://openairdocs.org/ntsb-events/000/sequence.md) - [Landing: Collision during takeoff/land](https://openairdocs.org/ntsb-events/490) (defining event); cases with it: [Timothy D Mccall STOL CH 750, 1 case](https://openairdocs.org/ntsb-events/490/sequence.md?model=05633EM), [All aircraft, 1,309 cases](https://openairdocs.org/ntsb-events/490/sequence.md) ## Analysis The pilot reported that while on a cross-country flight he experienced an “engine stumble,” which then returned to normal operation so he continued for about 12 more miles over open fields. During an attempted climbing turn, the engine sustained a “prolonged stumble” and a loss of power that did not improve. As the pilot set up for a forced landing on a road, the airplane’s vertical stabilizer impacted a power line, so he aborted the landing. The pilot made a climbing left turn as engine power was restored. The pilot continued the flight to his destination airport and landed without further incident. A witness reported seeing the airplane flying low in front of his property. The witness reported hearing engine noise and did not hear any indication of a rough running engine. The witness stated he heard a noise and then saw power lines moving. He reported the airplane flew under the power lines and then climbed up again. Postaccident examination of the airplane revealed substantial damage to the vertical stabilizer. A functional test run of the engine revealed that it achieved full power with no anomalies noted. The carburetors exhibited some fuel staining; however, examination of both carburetors revealed no malfunctions or failures that would have precluded normal operation. As a result, the reason for the reported loss of engine power could not be determined. Automatic dependent surveillance – broadcast (ADS-B) data showed the airplane climbed to an altitude of about 1,000 ft above ground level (agl) after takeoff. About 14 miles after departure, the airplane descended, and remained at altitudes below 300 ft agl until it collided with the power lines. The airplane then climbed to and maintained an altitude of 1,100 ft agl, before it descended to land at the destination airport. ## Factual narrative On May 2, 2023, about 2013 central daylight time, a Zenith STOL CH750 airplane, N750TK, sustained substantial damage when it was involved in an accident near Udall, Kansas. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that while en route to Cook Airfield (K50), Rose Hill, Kansas, he experienced an “engine stumble.” He descended toward open fields and the engine returned to normal operation. The pilot continued over open fields for about 12 more miles. During an attempted climbing turn, the engine sustained a “prolonged stumble” and a loss of power that did not improve. The pilot maneuvered the airplane for a forced landing to a road. During the landing attempt the airplane struck a power line. The pilot aborted the landing attempt, engine power was restored, and he flew about 10 miles to K50 for an uneventful landing. A witness reported seeing the airplane flying low towards his house. He provided a photo of the airplane in flight, right before it struck the power line (see Figure 1). He stated that he saw the airplane fly under power lines, heard a noise, and then saw the power lines moving. He stated that he heard engine noise and that there was no indication of a rough running engine. After striking the power lines, the airplane climbed and flew to the northwest at “treetop height.” Figure 1. A witness photo that shows the accident airplane right before it struck the power line. The airplane is circled in red and the power lines are labeled in yellow. Postaccident examination of the airplane revealed substantial damage to the vertical stabilizer. The engine’s right carburetor exhibited fuel staining around the choke housing and in the drip pan. The left carburetor had fuel staining around one screw on the choke housing. The throttle cable exhibited chafing where it passed through the firewall. The engine started and was run up to full rpm and no discrepancies were noted. The carburetors were removed and an examination revealed no indication of malfunction or failure that would have precluded normal operation. The throttle cable chafing did not inhibit carburetor operation. A review of the airplane’s logbooks revealed that the engine was installed on August 27, 2016. The last condition inspection was completed on January 4, 2023. At that time the engine had accumulated 591.76 hours. A review of ADS-B data showed the airplane departed Ponca City Regional Airport (PNC), Ponca City, Oklahoma, about 1939 and climbed to an altitude of about 1,000 ft agl. About 14 miles north of PNC, the airplane descended and remained at altitudes below 300 ft agl until the area of the power line collision. Then, the airplane climbed and ultimately reached the maximum altitude of the entire flight, about 1100 ft agl, before it descended to land on runway 35 at K50. ## Aircraft - Registration: [N750TK](https://openairdocs.org/aircraft/N750TK), registered now, S/N 75-7953, built 2014 (OpenAirDocs) - Reported make and model: ZENITH STOL CH750 - Registry model: [Timothy D Mccall STOL CH 750](https://openairdocs.org/model/timothy-d-mccall-stol-ch-750) (registry code 05633EM) (OpenAirDocs) - Registry engine: [Corvair 164](https://openairdocs.org/engine/corvair-164) (registry code 18002, reciprocating) (OpenAirDocs) - Category: Airplane, amateur-built - Serial number: 75-7953 - Year built: 2014 - Airframe hours: 609.68 - Engines: Rotax 100ULS 100 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: Mccall Timothy D - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Condition, January 4, 2023, 17.92 hours before - Departed: KPNC, Ponca City, OK - Destination: K50, Rose Hill, KS - Airport: K50, Cook Airfield - Equipment: Electronic primary flight display, Electronic flight bag or handheld device, ADS-B ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 65; injuries: none; private; airplane ratings: single-engine land; medical: class 3, with waivers/limitations; last flight review May 24, 2022; seat: left; flight hours: 665 total, 610 in this make and model, 14 in the last 90 days, 5 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Dusk - Wind: 10° at 7 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 59 °F, dew point 28 °F - Altimeter: 29.98 inHg - Observed at: KEGT, 13 nm away - METAR: KEGT 030115Z AUTO 01007KT 10SM CLR 15/M02 A2998 RMK AO2 T01481021,M ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Incident 20230502014029I](https://openairdocs.org/incident/20230502014029I), May 2, 2023: Timothy D Mccall STOL CH 750, Udall, KS, Minor damage. Overview: Airvraft experienced partial power lost then contacted power lines in the vicinity of Udall, KS. On scene investigation: On 05/08/2023 at 1330 I met… ## Docket (8 files) The files NTSB released with the investigation on May 9, 2024, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=107810. 9.3 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 11 pages, 2.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15806708&FileExtension=pdf&FileName=Aircraft%20incident%20report%20750TK_Redacted-Rel.pdf - Photos (item 2, PDF, 4 pages, 2.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15806005&FileExtension=pdf&FileName=photo%20array-Rel.pdf - FAA inspector's statement (item 3, PDF, 2 pages, 212 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15806303&FileExtension=pdf&FileName=N750TK%20R.%20Stevens%20Inspector%20Report%2006-27-2023-Rel.pdf - Memorandum for record a�� telephone interview, pilot (item 4, PDF, 1 page, 60 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15969117&FileExtension=pdf&FileName=MFR%20Pilot-Rel.pdf - Memorandum for record a�� telephone interview, witness (item 5, PDF, 2 pages, 213 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16985884&FileExtension=pdf&FileName=MFR%20Witness-Rel.pdf - Maintenance records (item 6, PDF, 2 pages, 823 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15972454&FileExtension=pdf&FileName=Docket%20Records_Redacted-Rel.pdf - Raw ADS-B data (item 7, XLSX, 3.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15975591&FileExtension=xlsx&FileName=20230503_AA1BBC_514465221_ADSB-Rel.xlsx - Maps of accident area (item 8, PDF, 1 page, 203 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15979748&FileExtension=pdf&FileName=Accident%20Area%20Map-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.