Amateur-built Pitts Special SPS-1 N330BL accident near Revere, Minnesota

Probable cause

The total loss of engine power during cruise flight due to fuel contamination and the inadequate design of the fuel system.

NTSB analysis

The airplane had not been flown for over 6 months prior to the accident flight. Before departure, the pilot added about 3 gallons of fuel to the existing fuel on board the airplane. The pilot did not find contamination when he drained fuel from the main fuel tank sump drain. About 20 minutes after departure, during cruise flight, the airplane experienced a total loss of engine power that led the pilot to conduct a forced landing on a road. The airplane nosed over during the landing. An examination of the airplane revealed that the airplane was not equipped, nor was it required to be equipped, with a fuel sump drain(s) for the wing tank, which drained into the main fuel tank. Water contamination was present in the fuel line leading to the carburetor, but no water contamination was noted when the main fuel tank sump—the only available sump—was drained. Accordingly, water was likely in the wing tanks and fed into the main tank after it was sumped. The water then entered the fuel lines. The lack of sump drains in the wing tanks is an inadequate design because it does not allow a pilot to remove all water from the fuel system.

Text from the NTSB. Open the NTSB docket for CEN12LA128 for the full record.