DEN90FA017 · Cessna 172RG
Cessna 172RG · Accident: in flight encounter with weather en route
From Laramie Regional Airport (LAR) to Rawlins Municipal Airport/Harvey Field (RWL)
Event
- NTSB case
- DEN90FA017
- 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
- 1 · 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
Cessna 172RG
- Aircraft type
- Cessna 172
- 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
- N4825V
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Laramie Regional Airport (LAR)To Rawlins Municipal Airport/Harvey Field (RWL), Rawlins, 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
- 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 › Aircraft control, not maintained
- Pilot in command › Spatial disorientation
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
THE PLT RECEIVED A WEATHER BRIEFING FOR A VFR FLT. THE BRIEFING INDICATED IFR WEATHER ALONG THE INTENDED ROUTE OF FLIGHT. THE PLT STATED HE WAS CONDUCTING THE FLT VFR BECAUSE HE 'DID NOT TRUST HIS INSTRUMENTS.' APPROXIMATELY ONE HOUR AFTER DEPARTURE FROM LARAMIE, WY, THE PLT REQUESTED THE LARAMIE WEATHER IN AN ATTEMPT TO RETURN. THE PLT RADIOED HE LOST HIS GYROS AND DECLARED AN EMERGENCY. THE FSS RECEIVED A SPECIAL VFR CLEARANCE DUE TO BELOW VFR MINIMUM WEATHER, BUT WAS UNABLE TO ISSUE IT DUE TO LOST RADIO COMMUNICATIONS. POST-ACCIDENT INVESTIGATION REVEALED THE VACUUM PUMP HAD BEEN INSTALLED WITHOUT THE SHEAR SHAFT COUPLING. THE AIRFRAME AND ENGINE LOGBOOKS DID NOT IDENTIFY PREVIOUS WORK PERFORMED OR PERSON(S) WHO MAY HAVE WORKED ON THE PUMP.
Probable cause
THE LOSS OF CONTROL OF THE AIRPLANE IN INSTRUMENT METEOROLOGICAL CONDITIONS AFTER THE PILOT BECAME SPATIALLY DISORIENTED. CONTRIBUTING TO THE ACCIDENT WAS THE FAILURE OF THE VACUUM SYSTEM WHICH RENDERED THE VACUUM/GYRO INSTRUMENTS INOPERATIVE. ALSO CONTRIBUTING TO THIS FAILURE WAS THE IMPROPER INSTALLATION OF THE VACUUM PUMP BY UNKNOWN PERSON(S).
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record DEN90FA017
- Event ID
- 20001213X29580
- Case number
- DEN90FA017
- 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 1989-11-01.
- API snapshot SHA-256: aa570230498ac6ce59c479b65d42e3ef8c154de89fbd30d97e1d3dc09d9b60d3; retrieved 2026-09-21T03:05:47.555Z.