WPR26LA072

NTSB accident investigation · Zenith 750 · Yacolt, WA · December 23, 2025

Accident · No injuriesClass 4 · LimitedFinal report
Date
December 23, 2025, 15:43 local (23:43 UTC)
Place
Yacolt, WA · Approx 5 miles? from WA87
Injuries
1 uninjured
Damage
Substantial damage
Phase of flight
Enroute
Aircraft
N186BGZenith 750
Defining event
Enroute-cruise: Loss of engine power (total)
Weather
Visual (VMC) · Day
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
FAA report
20251223019739A
Case key
202221

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.

On this page

Probable cause

A loss of engine power for undetermined reasons.

Findings · 1

NTSB’s coded findings. Those marked are part of the probable cause; the rest are factors or other findings. Under each, the cases with the same finding.

Engine (reciprocating)Aircraft › Aircraft power plant · Unknown/Not determinedScott Ahrens 750 SUPERDUTY: 1 caseAll aircraft: 497 casesProbable cause

Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event is the one that best describes the accident. Under each, the cases with the same event anywhere in their sequence.

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
Reported as
Zenith 750 (Super Duty)
Category
Airplane, amateur-built
Serial number
SD75-11850
Built
2025
Airframe hours
16
Engine
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

Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

Flight crew

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
71
Injuries
None
Certificate
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

Docket · 5

The files NTSB released with the investigation on April 14, 2026, on NTSB’s docket system: statements, records, photos and specialists’ reports. 7.2 MB in all.

FAA reports on this event · 1

The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.