Pilot Debrief

NORTH AMERICAN/SCHWAMM AT-6F near Fitchburg, MA — 2010-11-06

Final reportERA11LA050
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Date
2010-11-06
Location
Fitchburg, MA, USA
Airport
FIT
Aircraft
NORTH AMERICAN/SCHWAMM AT-6F
Registration
N164US
Category
Airplane
Highest injury
Fatal
Fatalities
1
Phase of flight
Approach

Probable cause

A total loss of engine power due to a cracked carburetor float and resulting carburetor malfunction.

NTSB narrative

The pilot was performing a local, revenue sightseeing flight with a passenger in the aft seat. The flight was recorded on a glareshield-mounted personal video recorder. About 12 minutes into the flight, the pilot commented about an unspecified problem; however, the flight continued. Conversation regarding the airplane’s fuel state indicated that there was adequate fuel on board for the flight. After air work and sightseeing, the flight returned to the local traffic pattern. After turning onto final approach for landing, the engine completely lost power. The pilot was unable to restart the engine, and the airplane crashed short of the runway. Postaccident examination of the carburetor revealed a visible crack in the soldered seam on one of the metal floats. Although there was some impact damage to the carburetor, the cracked float was located inside a fuel chamber that was undamaged. Further examination of the float fracture revealed that it was the result of a dent in the float. The fracture surface was coated with a lead-based corrosion product that was also on the inside of the float, suggesting that the crack had been open and corroding for an extended time period. It is likely that the crack in the float provided a fuel path that allowed the float to fill with fuel, resulting in a carburetor malfunction. Examination of the airplane’s records did not reveal documentation of recent carburetor maintenance.

Analysis

Primary failure mode
Engine power loss
First missed decision gate
Pilot could have checked fuel levels before approach to prevent engine failure.

NTSB coding

Evidence available

  • Photos
  • 11 docket documents
View NTSB final reportView NTSB docket

Docket documents11

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