FTW00LA068 · Mooney M20K
Mooney M20K · Accident: total loss of engine power (mechanical failure) en route
From Addison Airport (ADS) to Tyler Pounds Regional Airport (TYR)
Event
- NTSB case
- FTW00LA068
- 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
Mooney M20K
- 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
- N1157G
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Addison Airport (ADS), Addison, TXTo Tyler Pounds Regional Airport (TYR), Tyler, TX
- 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
- Engine assembly, gear › Failure
- Engine assembly, gear › Fatigue
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The pilot reported that the engine lost total power while in cruise flight between 1,500 feet and 2,000 feet agl. He executed a forced landing, during which the airplane contacted a fence post. During the postaccident examination of the engine, the crankshaft drive gear was observed fractured. Three consecutive gear teeth of the crankshaft drive gear separated, of which two were recovered. The crankshaft drive gear and gear teeth were examined at the NTSB Materials Laboratory and three areas of fatigue were observed. Each fatigue area originated at the relief radius at the root of one of the three separated teeth. No tooling marks or gouge marks were observed near the fracture surface or on the remainder of the crankshaft gear's teeth. The outermost nitrided layer of the crankshaft drive gear appeared smooth and no cracks were noted. Additionally, machining marks through the entire crankshaft drive gear appeared consistent.
Probable cause
The failure of the crankshaft drive gear as a result of fatigue, which resulted in a forced landing. A factor was the lack of suitable terrain for the forced landing.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record FTW00LA068
- Event ID
- 20001212X20365
- Case number
- FTW00LA068
- 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: e4cd309afb77c9edd95fefa111812fec361aac1efa93ce21667e0ca87698b08d; retrieved 2026-09-22T13:22:12.652Z.