Amateur-built TITAN 51 MUSTANG N43889 accident near Evans, Colorado

Probable cause

The builder's improper wiring of both fuel pumps to the battery-powered bus, which resulted in a total loss of engine power when the batteries failed because all power to the fuel pumps was lost.

NTSB analysis

The pilot reported that, about 15 minutes into the flight and 6 miles from his arrival airport, the airplane lost all engine and electrical power. The pilot established the best glide speed for the airplane, turned on the auxiliary fuel pump switch, and tried to extend the landing gear. When he realized that the electrically powered landing gear would not extend, he decided to land the airplane in a pasture next to a road. After touchdown, the airplane slid about 70 feet before coming to a stop. The pilot opened the canopy, turned off the fuel and all other switches, and exited the airplane.

An examination of the airplane's electrical system showed that neither of the airplane's 12-volt batteries would hold a charge. The examination also showed that both the main and auxiliary fuel pumps were wired to the battery-powered bus. According to the engine manufacturer's service representative, if a battery power failure occurs, the engine would quit running if both fuel pumps were connected to the battery bus instead of one being connected to the internal engine generator. When the batteries failed, both fuel pumps ceased operating, and the engine failed.

Text from the NTSB. Open the NTSB docket for CEN14LA168 for the full record.