Amateur-built II N10236 accident near Bulverde, Texas

Probable cause

A loss of engine power due to fuel starvation due to a blockage of the fuel tank outlet port.

NTSB analysis

The pilot reported that the amphibious airplane’s engine gradually lost partial power shortly after takeoff and he was unable to maintain altitude. He performed a forced landing in a field with the retractable landing gear in the retracted position. After touchdown on the hull, as the airplane slowed, the right wing settled to the ground and the right-wing sponson struck the ground. The airplane incurred substantial damage to the right wing and fuselage during the forced landing.

Postaccident examination of the airplane revealed that the fiberglass fuel tanks of the airplane had debris and deterioration. The resin used in construction of the fuel tanks was not compatible with automotive gasoline. The pilot/owner had never used automotive gasoline but could not attest to what previous owners had used. Further examination did not reveal any other preimpact anomalies with the engine that would have precluded normal operations.

Although there was a potential for carburetor icing at glide power, based on the available evidence and that the airplane was taking off at the time of the accident, the engine likely lost power due to fuel starvation caused by debris obstructing the fuel outlet port of the fuel tank.

Text from the NTSB. Open the NTSB docket for CEN22LA283 for the full record.