Amateur-built SONEX N10DA accident near Burnet, Texas

Probable cause

The pilot’s failure to maintain aircraft control, resulting in an aerodynamic stall. Contributing to the accident was the loss of engine power due to a clogged fuel screen that resulted in fuel starvation caused by the builder's inappropriate use of a fuel tank sealant in a plastic tank.

NTSB analysis

According to several witnesses, the pilot radioed that he was experiencing a loss of engine power and was attempting a forced landing. Witnesses who saw the airplane reported that during the forced landing attempt the nose of airplane dropped and the airplane subsequently impacted terrain in a nose-low attitude. An examination of the flight controls and airframe structure revealed no preaccident anomalies that would have prevented the pilot from maintaining aircraft control. An examination of the engine and fuel system revealed a white substance inside the main fuel tank which had clogged the fuel screen. Laboratory examination of this substance revealed that it was polyurethane. The sealant used to seal the fuel tank contained polyurethane designed to be used to bond the sealant to a metal tank. The airframe builder added this sealant to the accident airplane's plastic (polyethylene) tank when he encountered a leak within the fuel system at the fuel fitting. An examination of the remaining engine and systems revealed no anomalies.

Text from the NTSB. Open the NTSB docket for CEN10LA050 for the full record.