Stearman Aircraft C3-B N3440 accident near Stevenson, Washington

Probable cause

A loss of engine power due to fuel starvation from a piece of disintegrating gasket material that was blocking the fuel jet. Also causal was the failure of maintenance personnel to verify the condition of the gaskets when the carburetor was examined prior to installation on the engine.

NTSB analysis

The pilot reported that he had completed a cross-country flight reenacting the airmail route. During the flight, the pilot had applied carburetor heat, but the engine lost power. He attempted to restart the engine, but was unsuccessful; he then performed a forced landing in a field. During the landing roll, the airplane collided with a tree and sustained substantial damage. While the pilot had purchased the engine and carburetor that were over 60 years old, they were in new condition and had been in storage. A maintenance facility bench tested the carburetor and it checked within limits, but due to its pristine condition it was not disassembled prior to installation on the engine. The carburetor operated for 110 hours before disintegrating gasket material entered into the main fuel jet and disrupted the fuel flow, which allowed the engine to lose power. Postaccident examination of the carburetor showed that after the gasket material was removed from the jet the carburetor operated normally.

Text from the NTSB. Open the NTSB docket for SEA08LA206 for the full record.