NTSB Identification: SEA91LA249.
The docket is stored on NTSB microfiche number 46799.
Accident occurred Sunday, September 22, 1991 in SNOHOMISH, WA
Probable Cause Approval Date: 05/05/1993
Aircraft: CESSNA 177, registration: N3314T
Injuries: 2 Uninjured.
NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.
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.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: THE SEPARATION OF THE MIXTURE CONTROL CABLE (CORE) RESULTING FROM SEPARATION OF THE ADEL CLAMP ASSEMBLY AND IMPROPER ADJUSTMENT BY MAINTENANCE PERSONNEL.
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