SEA01LA067 · Republic RC-3
Republic RC-3 · Accident: airframe, component or system failure en route
From Mason Lake, WA to Tacoma Narrows Airport (TIW)
Event
- NTSB case
- SEA01LA067
- 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
Republic RC-3
- Aircraft type
- Republic RC-3
- 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
- N6295K
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Mason Lake, WATo Tacoma Narrows Airport (TIW), Tacoma, WA
- 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
- Airframe, component or system 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
- Miscellaneous, bolt/nut/fastener/clamp/spring › Fatigue
- Propeller system/accessories › Separation
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The commercial pilot stated that the airplane was in a cruise flight configuration at 1,500 feet mean sea level (msl) when he observed an engine over speed condition. The pilot reduced engine RPM and executed a forced water landing. Post-accident inspection of the airplane disclosed that the airplane's propeller had separated from the crankshaft flange. The remnants of three propeller bolts were recovered and shipped to the NTSB Materials Laboratory in Washington, D.C. for metallurgical examination. The examination disclosed that the propeller bolts fractured in a mode consistent with high vibratory tensile stress before the bolts failed due to insufficient torque on the bolts.
Probable cause
Fatigue fracture of the propeller attaching bolts resulting in the total separation of the propeller assembly from the crankshaft flange.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record SEA01LA067
- Event ID
- 20010330X00673
- Case number
- SEA01LA067
- 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: 621e46d3bf6a84790b511721f2ee872d70e1233fe3441416328fac70ccec7765; retrieved 2026-09-22T12:04:57.108Z.