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WPR21LA351 · George A. Thiel Just Aircraft Highla

21 Sept 2021 · Monroe, WA, United States

George A. Thiel Just Aircraft Highla · Accident: loss of engine power (partial) en route

From Auburn Municipal Airport (S50) to an unrecorded destination

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Event

NTSB case
WPR21LA351
Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
Accident
InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
Completed
Event fatalities
Unknown
Ground fatalities
Unknown
OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
General aviation
WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
Visual Meteorological Cond

George A. Thiel Just Aircraft Highla

Category
Airplane
RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
N488VG
Operator
Unknown
Onboard fatalities
Unknown
Route
From Auburn Municipal Airport (S50), Auburn, WATo not recorded
Aircraft age
About 8 years (built 2013)
Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
Part 91: General Aviation
Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
En route
Defining eventThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
Loss of engine power (partial)
DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
Substantial

Cause areas

  • Aircraft › Aircraft power plant
  • Environmental issues › Physical environment

Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.

NTSB narrative

The pilot of the experimental amateur built airplane reported that, after descending to a local river, he increased the throttle to add power and level off, but the engine did not respond. The engine lost total power, and he attempted an in-flight engine restart to no avail. The pilot initiated a landing to a nearby island in the river, however, during the landing, the airplane’s airspeed was fast, and braking was ineffective. The pilot turned the airplane to the right toward vegetation and subsequently impacted a sandbank. The airplane sustained substantial damage to the left-wing and the empennage. A postaccident examination of the throttle control linkage revealed that the throttle control had separated at the throttle control pivot arm. The bolt, washer and nut which secured the cable to the throttle control pivot arm had backed out and were not located during the examination. Additionally, a bolt, bushing binding and nut were used to secure the throttle control pivot arm to a cross-member located between the throttle control cable and the carburetor cable binding. The return spring is designed to open the throttle to the fully open throttle position when the throttle control malfunctions. The torque on the nut that secured the pivot arm to the cross-member was excessive and consequently prevented the pivot arm from allowing the return spring to open the throttle.

Probable cause

The in-flight malfunction of the throttle control pivot arm, which resulted in a total loss of engine power and the subsequent collision with terrain during the forced landing.

Verbatim NTSB analysis and probable cause from the NTSB dataset

Sources

NTSB record WPR21LA351
Event ID
20210922103943
Case number
WPR21LA351
Dataset
full-current
Source SHA-256
5cf380f0061817c0331a6b2d8cc7e0ee3a79bea469a1001dc5c10e56f35f5ab3
Source notes (4)
  • Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
  • Filled from the NTSB case API where the bulk record had no value: investigation status, cause areas. Values present in the bulk record are kept.
  • The date is the local date, which is the same as the UTC date the NTSB stores.
  • API snapshot SHA-256: b97a5e1e88594ab7451ad7be72b4b77dcad43bffd0a6477b00869d318a70e678; retrieved 2026-09-16T14:34:15.631Z.