# NTSB WPR26LA072: Zenith 750, N186BG, Yacolt, WA, December 23, 2025

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Class 4 · Limited · Final report
- Date: December 23, 2025, 15:43 local (23:43 UTC)
- Place: Yacolt, WA · Approx 5 miles? from WA87
- Coordinates: 45.873399, -122.4958
- Nearby events: https://openairdocs.org/map.md?lat=45.8734&lon=-122.4958&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Defining event: [Enroute-cruise: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report April 14, 2026
- Report: Approved by Office Director
- Investigation class: Class 4 - Basic report with no Prelim publish
- NTSB office: Western Pacific Region
- Parties: Federal Aviation Administration
- NTSB case key (mKey): 202221
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR26LA072
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/202221/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=202221
- Page: https://openairdocs.org/ntsb/WPR26LA072

## Probable cause

A loss of engine power for undetermined reasons.

## Findings

NTSB's coded findings; those marked are part of the probable cause.

- [Engine (reciprocating)](https://openairdocs.org/ntsb-findings/01058500): Aircraft › Aircraft power plant · Unknown/Not determined (probable cause); cases with it: [Scott Ahrens 750 SUPERDUTY, 1 case](https://openairdocs.org/ntsb-findings/01058500/cases.md?model=0564252), [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-cruise: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Scott Ahrens 750 SUPERDUTY, 1 case](https://openairdocs.org/ntsb-events/341/sequence.md?model=0564252), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md)

## Analysis

The pilot was returning to the airport while conducting a phase 1 test flight in an experimental airplane when he detected a burning odor. He scanned the engine instruments which all showed normal indications. Shortly after, about 4 miles from his home airport, the engine shut down. He reported his position and intentions on the local radio frequency and initiated a forced landing to a down sloping field. During the landing roll the airplane impacted terrain, sustaining substantial damage to the fuselage and wings. The pilot also reported that after he exited the airplane, he didn’t see any oil or water dripping from the cowling or oil spray on the windshield. At the time of the accident the airplane had accrued 16 hours of operation. The FAA conducted a postaccident examination of the experimental airframe and engine, which revealed no preimpact mechanical malfunctions or failures that would have precluded normal operation. The pilot further reported that he found an odor from one of the engine control unit (ECU) connectors, although a review of the electrical system by the FAA did not reveal any evidence of electrical system damage. The ECU was sent to the engine manufacturer and tested normally with a functioning engine. Based on this information, the reason for the loss of engine power could not be determined.

## Aircraft

- Registration: [N186BG](https://openairdocs.org/aircraft/N186BG), registered now, S/N SD75-11850, built 2025 (OpenAirDocs)
- Reported make and model: ZENITH 750 (Super Duty)
- Registry model: [Scott Ahrens 750 SUPERDUTY](https://openairdocs.org/model/scott-ahrens-750-superduty) (registry code 0564252) (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: SD75-11850
- Year built: 2025
- Airframe hours: 16
- Engines: Viking Aircraft Engines 195T 195 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Airworthiness certificate: Special, Experimental (Special)
- Last inspection: Condition, August 21, 2025, 16 hours before
- Departed: WA87, Battle Ground, WA
- Airport: WA87, Parkside Airpark
- Equipment: Video recording device, ADS-B, Electronic primary flight display

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 71; injuries: none; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane, helicopter; medical: basicmed, with waivers/limitations; last flight review September 14, 2025; seat: left; flight hours: 6,400 total, 25 in this make and model, 5,560 as pilot in command, 15 in the last 90 days, 3 in the last 30 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: calm
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 46 °F, dew point 39 °F
- Altimeter: 29.75 inHg
- Icing: Unknown
- Turbulence: Unknown
- Observed at: KVUO, 17 nm away
- METAR: METAR KVUO 232253Z AUTO 00000KT 10SM CLR 08/04 A2975 RMK AO2 SLP076 T00780039

## 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 20251223019739A](https://openairdocs.org/incident/20251223019739A), Dec 23, 2025: Scott Ahrens 750 SUPERDUTY, Yacolt, WA, Substantial damage. On December 23, 2025 a commercially rated pilot took off from WA87 at approximately 15:17 PST for another phase one test flight. The aircraft had been refueled…

## Docket (5 files)

The files NTSB released with the investigation on April 14, 2026, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=202221. 7.2 MB in all.

- Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 10 pages, 4.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=19767456&FileExtension=pdf&FileName=N186BG%206120-1_Redacted-Rel.pdf
- Mor video description of ecu test (item 2, PDF, 1 page, 67 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=20077466&FileExtension=pdf&FileName=MOR%20Video%20of%20ECU%20Test-Rel.pdf
- Photo array (courtesy of the pilot/owner) (item 3, PDF, 6 pages, 1.9 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=20114588&FileExtension=pdf&FileName=Photo%20Array-Accident%20Site%20(Courtesy%20of%20the%20Owner)-Rel.pdf
- Photo array (courtesy of the FAA) (item 4, PDF, 3 pages, 543 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=20114048&FileExtension=pdf&FileName=Photo%20Array-Wreckage%20Exam%20(Courtesy%20of%20the%20FAA)-Rel.pdf
- FAA examination notes-email (item 5, PDF, 1 page, 207 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=20077839&FileExtension=pdf&FileName=FAA%20Exam%20Email_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.

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