MIA04LA127 · Mooney M20F
Mooney M20F · Accident: total loss of engine power (mechanical failure) en route
From DeKalb Peachtree Airport (KPDK) to Shreveport Downtown Airport (KDTN)
Event
- NTSB case
- MIA04LA127
- 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
Mooney M20F
- Aircraft type
- Mooney M20
- 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
- N9708M
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From DeKalb Peachtree Airport (KPDK), Atlanta, GATo Shreveport Downtown Airport (KDTN), Shreveport, LA
- 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
- Total 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
- Pilot in command › Unsuitable terrain or takeoff/landing/taxi area, encountered
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
The pilot stated that he performed a preflight inspection of the airplane and noted the oil capacity was full (8 quarts). Approximately 2 hours into the flight while flying at 10,500 feet, the engine began running rough. He advised air traffic control (ATC), and attempts to correct the rough running engine were unsuccessful. The flight continued and shortly afterwards, the engine developed a severe roughness and he then heard a bang with smoke entering the cockpit. He declared "mayday" with ATC, and requested vectors to the nearest airport. Unable to land there, he executed a forced landing on a nearby highway and collided with a vehicle during the landing roll-out. The No. 3 cylinder was found separated from the crankcase, and all cylinder studs and/or thru-bolts exhibited various forms of fatigue. The No. 3 cylinder connecting rod bolts which were fractured exhibited evidence of either bending or shear overstress. The No. 2 cylinder connecting rod bearing was found welded to the crankpin, and a piece of aluminum lined bearing material was found inside the oil passage of the No. 2 cylinder crankpin journal. Fretting was noted at the No. 3 cylinder contact area, and also at the split-line surface of the right crankcase half at the main bearing locations. The fretting was the greatest at the cylinder contact area between studs Nos. 1 and 2, and also at the split line surface on the right crankcase half at the No. 3 main bearing location. The engine had accumulated 1,390 hours since major overhaul and approximately 873 hours since the No. 3 cylinder was removed and reinstalled.
Probable cause
A loss of engine power due to the fatigue failure of all studs and/or thru-bolts of the No. 3 cylinder for undetermined reasons causing separation of the cylinder. Contributing to the accident was the unsuitable terrain encountered by the pilot.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record MIA04LA127
- Event ID
- 20040921X01475
- Case number
- MIA04LA127
- 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, coordinates. 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: 33013a556a68eaa95a2fc158236bf9562a1bcadb00583fd93a9a22d928fc66f5; retrieved 2026-09-22T06:46:16.591Z.