What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
Pilot was taxiing west on taxiway c and experienced an increase in engine power that was described as "close to full power."
No engine indications were observed and this power setting was estimated by the pilot.
The pilot applied brakes, retarded the throttle to idle, and pulled the mixture to idle cutoff.
During this process the aircraft departed the taxiway to the left and impacted a snow bank flipping over forward and coming to rest upside down.
The pilot reported the engine was at full power for about 5 seconds before impacting the snow bank.
The pilot stated that the throttle was not advanced and believes the engine was making full power even though the throttle was at idle.
A post accident investigation revealed that all carburetor linkages were hooked up and making full travel in both directions. The carburetor was examined and the venturi and throttle plate appeared normal and intact.
As the FAA filed it
PILOT WAS TAXIING WEST ON TAXIWAY C AND EXPERIENCED AN INCREASE IN ENGINE POWER THAT WAS DESCRIBED AS "CLOSE TO FULL POWER."
NO ENGINE INDICATIONS WERE OBSERVED AND THIS POWER SETTING WAS ESTIMATED BY THE PILOT.
THE PILOT APPLIED BRAKES, RETARDED THE THROTTLE TO IDLE, AND PULLED THE MIXTURE TO IDLE CUTOFF.
DURING THIS PROCESS THE AIRCRAFT DEPARTED THE TAXIWAY TO THE LEFT AND IMPACTED A SNOW BANK FLIPPING OVER FORWARD AND COMING TO REST UPSIDE DOWN.
THE PILOT REPORTED THE ENGINE WAS AT FULL POWER FOR ABOUT 5 SECONDS BEFORE IMPACTING THE SNOW BANK.
THE PILOT STATED THAT THE THROTTLE WAS NOT ADVANCED AND BELIEVES THE ENGINE WAS MAKING FULL POWER EVEN THOUGH THE THROTTLE WAS AT IDLE.
A POST ACCIDENT INVESTIGATION REVEALED THAT ALL CARBURETOR LINKAGES WERE HOOKED UP AND MAKING FULL TRAVEL IN BOTH DIRECTIONS. THE CARBURETOR WAS EXAMINED AND THE VENTURI AND THROTTLE PLATE APPEARED NORMAL AND INTACT.
NTSB investigation
The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.