DEN04LA070 · Crimmins Smyth Sidewinder
Crimmins Smyth Sidewinder · Accident: loss of engine power en route
From Hot Springs County Airport (THP) to Casper-Natrona County International Airport (CPR)
Event
- NTSB case
- DEN04LA070
- 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
- API-reported fatalities
- 0 · all aircraft and ground
- 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
Crimmins Smyth Sidewinder
- Aircraft type
- Crimmins SMYTH SIDEWINDER
- 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
- N92AC
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Hot Springs County Airport (THP), Thermopolis, WYTo Casper-Natrona County International Airport (CPR), Casper, WY
- Aircraft age
- Not recorded
- 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 · cruise
- First occurrenceThe 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
- Also codedOther events the NTSB coded in the sequence, such as a wire strike after a loss of power. Flight Findings uses them for its kinds of event. Glossary
- Fuel contamination
- 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
- Fluid, fuel › Contamination
- Fuel system, selector/valve › Blocked(total)
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
After refueling to capacity, the pilot took off to ferry his newly-purchased airplane it to his home base. After 1 hour in cruise flight at 9,500 feet msl, the engine --- which had been producing 2,500 rpm --- began "surging" and started losing power. Carburetor heat was opened and the mixture was adjusted, but the engine continued to lose power. Cylinder head temperature, oil temperature, and oil pressure indicated normal parameters. As the airplane began losing altitude, the pilot decided to land in an open area. During the landing rollout, the nose and right main landing gears were torn off, and the left main landing gear folded underneath the airplane. The firewall was buckled and there was wing damage. Later examination of the fuel selector valve a considerable amount of fine grit inside the fuel screen. Similar grit was seen inside the fuel tank. The airplane was given a conditional inspection on May 6, 2004. Prior to that, the last conditional inspection was on August 1, 1996. Tachometer time between these two inspections was 178.9 hours. At the last inspection, the fuel tank was removed, cleaned by a radiator shop, and reinstalled in the airplane.
Probable cause
fuel starvation due to contamination, resulting in the fuel selector valve becoming totally blocked. Contributing factors were the inadequate conditional inspection, and the lack of nsuitable terrain on which to make a forced landing.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record DEN04LA070
- Event ID
- 20040511X00583
- Case number
- DEN04LA070
- Dataset
- historical-pre2008
- Source SHA-256
- 89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
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, coordinates. 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: 14d88633d7c3fd99fb74a839d242ebc464f41b94551d0fb12ddfc6b6af2b6db6; retrieved 2026-09-22T07:36:27.374Z.