# NTSB CEN20LA412: Zenith CH 750, N210WP, Montrose, MO, September 20, 2020 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: September 20, 2020, 11:45 local (16:45 UTC) - Place: Montrose, MO - Coordinates: 38.25, -93.889999 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=38.2500&lon=-93.8900&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute: Electrical system malf/failure](https://openairdocs.org/ntsb-events/332) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Central Region - Parties: FAA - NTSB case key (mKey): 102017 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN20LA412 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/102017/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=102017 - Page: https://openairdocs.org/ntsb/CEN20LA412 ## Probable cause A total loss of engine power due to an electrical overload in the engine control unit wiring system; the electrical overload occurred as a result of improper installation by the airplane builder. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Electrical power system: electrical pwr sys wiring](https://openairdocs.org/ntsb-findings/01022497): Aircraft › Aircraft systems · Malfunction (probable cause); cases with it: [Prosch William R CH 750, 1 case](https://openairdocs.org/ntsb-findings/01022497/cases.md?model=056328H), [All aircraft, 44 cases](https://openairdocs.org/ntsb-findings/01022497/cases.md) - [Maintenance: installation](https://openairdocs.org/ntsb-findings/02062035): Personnel issues › Task performance · Owner/builder (probable cause); cases with it: [Prosch William R CH 750, 1 case](https://openairdocs.org/ntsb-findings/02062035/cases.md?model=056328H), [All aircraft, 371 cases](https://openairdocs.org/ntsb-findings/02062035/cases.md) - [Terrain: rough terrain](https://openairdocs.org/ntsb-findings/03021015): Environmental issues › Physical environment · Contributed to outcome (probable cause); cases with it: [Prosch William R CH 750, 1 case](https://openairdocs.org/ntsb-findings/03021015/cases.md?model=056328H), [All aircraft, 442 cases](https://openairdocs.org/ntsb-findings/03021015/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute: Electrical system malf/failure](https://openairdocs.org/ntsb-events/332) (defining event); cases with it: [Prosch William R CH 750, 1 case](https://openairdocs.org/ntsb-events/332/sequence.md?model=056328H), [All aircraft, 182 cases](https://openairdocs.org/ntsb-events/332/sequence.md) - [Enroute: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341); cases with it: [Prosch William R CH 750, 1 case](https://openairdocs.org/ntsb-events/341/sequence.md?model=056328H), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Emergency descent: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Prosch William R CH 750, 1 case](https://openairdocs.org/ntsb-events/470/sequence.md?model=056328H), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The pilot of the experimental, amateur-built airplane was en route to the destination airport when the engine momentarily lost power. The pilot immediately selected the alternate fuel pump and engine control unit (ECU), and the engine regained power. About 5 minutes later, the engine lost total power, and the pilot attempted to restart the engine. The engine restart was unsuccessful, and the pilot performed a forced landing to a field, during which the airplane nosed over and came to rest inverted, resulting in substantial damage to the left wing and rudder. Postaccident examination of the airplane revealed that the main fuse block was discolored and exhibited internal thermal damage. An automotive blade-type fuse that connected to both primary and secondary fuel pumps and primary and backup ECUs displayed arcing signatures and had failed. According to the engine manufacturer, the primary and secondary ECUs should have been wired directly to the main bus and should not have contained a fuse. The improper installation of the airplane’s electrical system resulted in an overloaded electrical system for the installed fuse. After bypassing the failed electrical system, an engine test run was performed. The engine started and operated normally with no mechanical issues noted. ## Factual narrative On September 20, 2020, about 1145 central daylight time, an experimental, amateur-built CH 750 airplane, N210WP, was substantially damaged when it was involved in an accident near Montrose, Missouri. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. According to the pilot, while enroute to his destination airport, the engine momentarily lost power. He immediately selected the alternate fuel pump and engine control unit (ECU), and the engine regained power. About 5 minutes later, the engine lost total power, and the pilot attempted to restart the engine. The engine restart was unsuccessful, and the pilot initiated a forced landing to a field. During the forced landing, the airplane's landing gear contacted the high vegetation, and the nose impacted terrain. The airplane nosed over and came to rest inverted. The airplane sustained substantial damage to the left wing leading edge and the rudder. Postaccident examination of the airplane revealed that the main fuse block, located behind and under the instrument panel, was discolored and exhibited internal thermal damage. An automotive blade-type fuse, that connected to both primary and secondary fuel pumps and primary and backup ECUs, displayed arcing signatures, and had failed. According to the engine manufacturer, who responded to the accident site, the primary and secondary ECUs should have been wired directly to the main bus and should not have contained a fuse. After bypassing the failed electrical system, an engine test run was performed. The engine started and operated normally with no mechanical issues noted. The accident airplane had not been modified in accordance with an engine manufacturer service bulletin that recommended an ECU wiring upgrade. The upgrade removes the ECU select switch to operate on a single computer only. ## Aircraft - Registration: [N210WP](https://openairdocs.org/aircraft/N210WP), registered now, S/N 75-8690, built 2014 (OpenAirDocs) - Reported make and model: ZENITH CH 750 - Registry model: [Prosch William R CH 750](https://openairdocs.org/model/prosch-william-r-ch-750) (registry code 056328H) (OpenAirDocs) - Registry engine: [Viking 110](https://openairdocs.org/engine/viking-110) (registry code 63700, reciprocating) (OpenAirDocs) - Category: Airplane, amateur-built - Serial number: 75-8690 - Year built: 2014 - Airframe hours: 74.2 - Engines: Viking Aircraft Engines 110 110 hp reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Condition, July 8, 2020 - Departed: GLY, Clinton, MO - Destination: 0KS8, Parsons, MO - Equipment: Electronic primary flight display, ADS-B, Electronic flight bag or handheld device, Electronic multifunction display ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 52; injuries: none; private; airplane ratings: single-engine land; medical: class 3, without waivers/limitations; last flight review September 26, 2019; seat: left; restraint: 3-point; flight hours: 124 total, 52 in this make and model, 64 as pilot in command, 22 in the last 90 days, 14 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 140° at 8 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 64 °F, dew point 52 °F - Altimeter: 30.29 inHg - Observed at: GLY, 12 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 20200920017159A](https://openairdocs.org/incident/20200920017159A), Sep 20, 2020: Prosch William R CH 750, Deepwater, MO, Substantial damage. Pilot took off from kgly, Clinton Regional Airport, MO, at approximately 1115 CST headed for a private Kansas airstrip, 0KS8. At approximately 1130 CST at… ## Docket (5 files) The files NTSB released with the investigation on June 10, 2022, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=102017. 23.8 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 11 pages, 875 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11404060&FileExtension=pdf&FileName=6120.1%20Pilot_Operator%20Aircraft%20Accident_Incident%20Report_Redacted-Rel.pdf - Condition inspection maintenance record (item 2, PDF, 1 page, 21.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11404345&FileExtension=pdf&FileName=Condition%20Inspection%20Entry_Redacted-Rel.pdf - Examination summary - engine manufacturer (item 3, PDF, 2 pages, 133 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11408886&FileExtension=pdf&FileName=Examination%20Summary_Redacted-Rel.pdf - Viking engine service bulletin (item 4, PDF, 3 pages, 724 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11404813&FileExtension=pdf&FileName=Viking%20Engine%20Service%20Bulletin-Rel.pdf - Photo array (item 5, PDF, 3 pages, 389 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11404560&FileExtension=pdf&FileName=Photo%20Array-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.