DEN99FA012 · Piper PA-28-235
Piper PA-28-235 · Accident: in flight encounter with weather en route
From Mobridge Municipal Airport (MBG) to Billings Logan International Airport (BIL)
Event
- NTSB case
- DEN99FA012
- 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
- 2 · all aircraft and ground
- Ground fatalities
- 0
- 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
- Instrument Meteorological Cond
Piper PA-28-235
- Aircraft type
- Piper PA-28
- 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
- N8537N
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Mobridge Municipal Airport (MBG), Mobridge, SDTo Billings Logan International Airport (BIL), Billings, MT
- 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
- In flight encounter with weather
- 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
- Visual flight rules (VFR) flight into instrument meteorological conditions (IMC)
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Destroyed
Cause areas
- Pilot in command › Flight into adverse weather, initiated
- Pilot in command › VFR flight into imc, inadvertent
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The non-instrument rated pilot departed on a VFR flight plan direct to his destination (altitude of 6,500 feet msl). Approximately 25 minutes after departure, he diverted south and then west. Approximately 90 minutes after takeoff, the pilot radioed Flight Watch to request a weather update. At that time, he said that 'it was getting a little soupy out here.' Sunset was at 1847. The weather conditions en route, at 1836, were deteriorating, with cloud ceilings lowered to 1,500 feet agl and scattered clouds at 800 feet agl. The VOR, near the accident site, was inoperable due to electrical power failure. The pilot radioed Flight Watch at 1845, and requested help to identify his location. The airplane impacted the mountain at approximately 1850 at approximately 7,000 feet msl. The accident site was approximately 100 nm south of his flight plan route.
Probable cause
The non-instrument rated pilot's initiated flight into adverse weather conditions and inadvertently flew into IMC weather conditions. Factors were the low ceiling weather conditions, the dark night light conditions, and a non operating VOR navigational aid.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record DEN99FA012
- Event ID
- 20001211X11233
- Case number
- DEN99FA012
- 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: local date, investigation status. Values present in the bulk record are kept.
- The date is the local date; the NTSB stores the UTC date 1998-10-19.
- API snapshot SHA-256: 9a7e15e3ab4a716ec6043928103bc261e1c23c7bf4b934c24be79d7a2cde3fdb; retrieved 2026-09-20T22:20:57.071Z.