WPR10LA076 · Beech 35-33
Beech 35-33 · Accident: collision with terrain/object (non-CFIT) during landing
From St George Regional Airport (SGU) to Provo Municipal Airport (PVU)
Event
- NTSB case
- WPR10LA076
- 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
Beech 35-33
- Aircraft type
- Beechcraft 35
- 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
- N316Z
- Operator
- Mark Dwayne Thorn
- Onboard fatalities
- Unknown
- Route
- From St George Regional Airport (SGU), St. George, UTTo Provo Municipal Airport (PVU), Provo, UT
- 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
- Landing
- 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
- Collision with terrain/object (non-CFIT)
- 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
- Not determined › Not determined
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
Witnesses monitoring the common traffic advisory frequency for the pilot's intended destination reported that they overheard a radio transmission “mayday mayday, I am at the point of the mountain, 5,100 feet, my engine just quit.” Witnesses located adjacent to the accident site reported observing the airplane on a westerly heading near a major interstate when it suddenly banked to the right to a northerly heading before it descended into terrain. Examination of the accident site revealed that the airplane came to rest upright in a grassy, snow-covered area. The fuel selector valve was observed in the “right main” fuel tank position. The wreckage recovery company reported the airplane contained sufficient quantities of aviation fuel in the left and right main fuel tanks, and a minimal amount of fuel was found in the left and right auxiliary tanks. Examination of the recovered airframe revealed no mechanical anomalies that would have precluded normal operation. The recovered engine was removed from the airframe and subsequently installed on an engine test stand. The engine was successfully run at various power settings with no anomalies noted. Due to the pilot's injuries, he reported no memory of the accident sequence.
Probable cause
The loss of engine power during cruise flight for undetermined reasons.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record WPR10LA076
- Event ID
- 20091210X11649
- Case number
- WPR10LA076
- Dataset
- full-current
- Source SHA-256
- 5cf380f0061817c0331a6b2d8cc7e0ee3a79bea469a1001dc5c10e56f35f5ab3
Source notes (5)
- 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. 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: bc6538074a2aabab9b1790b93f85c6c696f99cd3bf6f1653ec7819fa47377722; retrieved 2026-09-15T13:33:56.714Z.
- Corrected after a review of the NTSB narrative, which states these values explicitly: destination. Transposed identifier; Provo Municipal Airport is PVU.