DEN83LA135 · Cessna TU206G
Monarch Aviation Cessna TU206G · Accident: partial loss of engine power (mechanical failure) en route
From Grand Junction Regional Airport (GJT) to Denver International Airport (DEN)
Event
- NTSB case
- DEN83LA135
- 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
- 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
- Visual Meteorological Cond
Cessna TU206G
- Aircraft type
- Cessna 206
- 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
- N732ZQ
- Operator
- Monarch Aviation
- Onboard fatalities
- Unknown
- Route
- From Grand Junction Regional Airport (GJT), Grand Junction, COTo Denver International Airport (DEN), Denver, CO
- 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
- Partial loss of engine power (mechanical failure)
- 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
- Exhaust system, turbocharger › Improper
- Exhaust system, turbocharger › Loose
- Exhaust system, turbocharger › Separation
- Other maintenance personnel › Maintenance, inspection, inadequate
Approximate · Estimated position: the centre of Molina, CO, the place the record names. Not the accident site.
NTSB narrative
THE PILOT HAD LEVELED OFF AT 17500 FT MSL WHEN THE ENGINE MADE A DETONATING SOUND AND LOST POWER. MANIFOLD PRESSURE WENT TO ABOUT 12 INCHES. FUEL PRESSURE WAS NORMAL BUT THE CYLINDER HEAD TEMPERATURE FELL RAPIDLY. AT 9000 FT MSL THE ENGINE SURGED TO ABOUT 16 INCHES OF MANIFOLD PRESSURE. WHEN THE PILOT LEANED THE MIXTURE THE ENGINE VIBRATED SEVERELY SO THE PILOT SECURED THE ENGINE. POST ACCIDENT INVESTIGATION REVEALED THAT THE RUBBER HOSE FROM THE TURBOCHARGER COMPRESSOR DUCT TO THE THROTTLE BODY DUCT HAD SEPARATED.
Verbatim NTSB analysis from the NTSB dataset
Sources
NTSB record DEN83LA135
- Event ID
- 20001214X43298
- Case number
- DEN83LA135
- 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: 1e50e99525e44405d0e0e95458bd29a79c2be9cf1f5141bba59c80cabe72e829; retrieved 2026-09-22T02:39:37.062Z.