Amateur-built Fighter Escort Wings N2051P accident near Pueblo, Colorado

Probable cause

An internal failure of one of the electrical system’s two batteries combined with the inadequate electrical system design, which resulted in a total loss of engine power.

NTSB analysis

The pilot reported that there was an electrical system failure during the cruise portion of the test flight, which resulted in insufficient voltage to maintain engine operation using either the primary or secondary battery circuits. Following the total loss of engine power, the pilot elected to perform a wheels-up landing on a gravel road. The non-certificated automobile engine that was installed in the airplane was equipped with a computer-controlled electronic ignition system and high-pressure fuel pumps. According to the pilot/builder, the airplane incorporated two 12-volt batteries wired in parallel to supply voltage to the main power bus to power the engine systems. Postaccident examination revealed that the primary battery had an internal short and would not take a charge. The secondary battery was found below normal service voltage, but could be recharged. Postaccident testing revealed that the two batteries were not isolated from each other; as a result, an internal short of one of the two batteries could drain the other battery’s charge. No anomalies were found with the remaining electrical system components or wiring paths.

Text from the NTSB. Open the NTSB docket for CEN12LA389 for the full record.