Casper Air Service Mitsubishi MU-2B-35 accident
Mitsubishi MU-2B-35 · Accident: in flight collision with terrain/water on approach
From Central Wyoming Regional Airport (RIW) to Casper-Natrona County International Airport (CPR)
Event
- NTSB case
- SEA93FA088
- 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
- 4 · 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
- Charter & commuter
- 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
Mitsubishi MU-2B-35
- Aircraft type
- Mitsubishi MU-2
- 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
- N96JP
- Operator
- Casper Air Service
- Onboard fatalities
- Unknown
- Route
- From Central Wyoming Regional Airport (RIW), Riverton, WYTo Casper-Natrona County International Airport (CPR), 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 135: Air Taxi & Commuter
- 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
- Approach · IFR initial approach
- 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 collision with terrain/water
- 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 › Proper altitude, not maintained
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
THE AIRCRAFT WAS ON AN AIR AMBULANCE (EMS) FLIGHT AND WAS CLEARED FOR THE ILS RUNWAY 8 APPROACH AT CASPER, WY. RADAR DATA SHOWED THE AIRCRAFT TRACKING AND DESCENDING NORMALLY ON THE DME ARC, UNTIL IT WAS BELOW RADAR COVERAGE FOR THE AREA. SUBSEQUENTLY, IT COLLIDED WITH THE TOP OF A RIDGE, ALONG THE LOCALIZER CENTERLINE, BEFORE REACHING THE OUTER MARKER, ABOUT 8 MILES FROM THE AIRPORT. ELEVATION OF THE CRASH SITE WAS ABOUT 5800 FEET; MINIMUM DESCENT ALTITUDE BEFORE INTERCEPTING THE ILS GLIDE SLOPE WAS 7100 FEET; CROSSING ALTITUDE AT THE OUTER MARKER WAS 6700 FEET.
Probable cause
FAILURE OF THE PILOT TO MAINTAIN PROPER ALTITUDE DURING THE NIGHT IFR APPROACH IN INSTRUMENT METEOROLOGICAL CONDITIONS (IMC).
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record SEA93FA088
- Event ID
- 20001211X12240
- Case number
- SEA93FA088
- 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. 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: 6a78e22f695e0b4dab3ffd3b924f9e3fac692764e6129bd81cf4b3a601939044; retrieved 2026-09-18T13:52:49.065Z.