SEA91LA249 · Cessna 177
Sigmet Cessna 177 · Accident: partial loss of engine power (mechanical failure) en route
From Tacoma Narrows Airport (TIW) to an unrecorded destination
Event
- NTSB case
- SEA91LA249
- 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 177
- Aircraft type
- Cessna 177
- 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
- N3314T
- Operator
- Sigmet
- Onboard fatalities
- Unknown
- Route
- From Tacoma Narrows Airport (TIW), Tacoma, WATo not recorded
- 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
- Mixture control, cable › Separation
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
DURING CRUISE A PARTIAL POWER LOSS OCCURRED AND THE PILOT, UNABLE TO REACH A SUITABLE AIRPORT, EXECUTED A FORCED LANDING. POST CRASH EXAMINATION REVEALED THAT THE MIXTURE CONTROL CABLE CORE HAD SEPARATED AT THE MIXTURE CONTROL ARM BOLT ADJACENT TO THE CARBURETOR. ADDITIONALLY, THE ADEL CLAMP ASSEMBLY RETAINING THE MIXTURE CONTROL CABLE NEAR THE MIXTURE CONTROL ARM WAS OBSERVED TO BE SEPARATED. THE SEPARATED CABLE CORE WAS DUE TO REVERSE BENDING FATIGUE CRACKING CONSISTENT WITH EXCESSIVE VIBRATORY LOADS APPLIED TO THE CABLE AS A RESULT OF THE SEPARATED ADEL CLAMP ASSEMBLY. THE SEPARATED ADEL CLAMP WAS DUE TO EXCESSIVE TWISTING LOADS APPLIED TO THE CLAMP. DURING THE FORCED LANDING ROLLOUT, WHICH WAS EXECUTED ON ROUGH TERRAIN, THE NOSE WHEEL ASSEMBLY COLLAPSED.
Probable cause
THE SEPARATION OF THE MIXTURE CONTROL CABLE (CORE) RESULTING FROM SEPARATION OF THE ADEL CLAMP ASSEMBLY AND IMPROPER ADJUSTMENT BY MAINTENANCE PERSONNEL.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record SEA91LA249
- Event ID
- 20001212X18209
- Case number
- SEA91LA249
- 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 1991-09-23.
- API snapshot SHA-256: 733e86b079281f2b512929fa11b085603c6aa4f833d3a376e90c85ae087e83d6; retrieved 2026-09-23T03:40:01.958Z.