Departure and Initial Flight
The flight departed using fuel from the main fuel tanks to supply the engine and climbed to altitude. Subsequently, the pilot utilized fuel from the electrically driven auxiliary fuel system.
Engine Failure and Restart
The pilot reported that the engine quit 1 hour and 15 minutes after switching to the auxiliary fuel system. He determined that there was a failure or malfunction of the electrical system. Fuel from the main tanks was then used to supply the engine, and the engine was restarted.
Divert and Fuel Transfer Attempt
The flight diverted to an alternate airport. The pilot attempted to supply fuel to the engine from the auxiliary fuel tank by turning on the shutoff valve and both fuel pumps, but was unsuccessful.
Final Engine Failure and Ditching
The engine eventually quit due to fuel exhaustion in the main fuel tanks. The pilot ditched the aircraft near an island, swam to it, and was rescued 26 hours later. The aircraft was not recovered.
Pilot's Assessment
The pilot stated that he believed the fuel pumps overloaded the electrical system but, in retrospect, believes the alternator failed. He noted that the auxiliary fuel system incorporates two electric pumps, but only one is to be used for normal operation; the second pump is to be used only for a failure or malfunction of the first pump.