Cessna 310/T310C
Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Sea; Flight Crew Commercial
Flight Crew Last 90 Days 25; Flight Crew Total 1900; Flight Crew Type 350
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Fuel Issue
Air Traffic Control Provided Assistance; Flight Crew Inflight Shutdown; Flight Crew Diverted; Flight Crew Landed in Emergency Condition
Aircraft; Human Factors
Enroute at 8000 ft; over water. Air temp roughly 0 degrees C. Approximately 2:20 elapsed flight time to that point.The procedure for fuel management in the Cessna 310 is to run from the main (tip) tanks for approximately 1 hour; then switch to auxiliary wing tanks. After consuming fuel in the auxiliary wing tanks (the 40.5 gal total capacity in the auxiliary tanks in this aircraft is normally consumed after 1-1.25 hour flight time); the fuel selector is returned to the main tanks; which are typically near full; having received the return fuel from the injection system while running on the auxiliary tanks. On some occasions; I elect to run the auxiliary fuel system to complete exhaustion; in order to consume all available fuel and to verify the fuel gauge empty indication. This procedure; while not used on every flight; has never resulted in a problem in an engine immediately resuming operation upon returning fuel supply to the main tanks after the first indication of fuel starvation as the auxiliary tanks are run to exhaustion. In this case; however; the Left Engine failed to resume normally after returning to the main tanks. Attempts over a 2-3 minute period to restart following the checklist procedure failed to result in the engine restarting. Rather than continue in the high-drag configuration with the propeller wind milling; and unclear as to the reason for a failure to restart; I elected to feather and secure the Left Engine; and land. ATC was helpful and responsive in providing nearest airport and runway information; and suggested a turn to [nearest suitable airport]; where a controlled and uneventful single-engine landing was made with no damage to the aircraft and no injuries. When on the ground; I consulted by telephone with my home-field mechanic who suggested a series of steps to determine any discernable cause.  After roughly 1 hour on the ground; with air temps in the 50's F; and with the fuel selector left in the mains position as it was during the last airborne restart attempt; the Left Engine primed and started normally. A high-power run-up and monitoring of fuel flows during a takeoff roll were normal; as was the next flight leg; during which leg the tanks were again switched without a problem. The auxiliary tanks; however; were not run to exhaustion. Note that in no prior case has water or any contamination ever been found in sumping the fuel system; the aircraft is stored in a heated hangar at its home field; and was stored in a heated hangar the night before the flight under discussion.While I cannot be certain that further persistence in attempting a restart may have succeeded; it seemed to me that with continued passage of time the likelihood of restart decreased; and risk to the flight built while the aircraft remained in a high-drag configuration.
C310 pilot reported the left engine failed due to fuel exhaustion and would not restart when a new tank was selected. Engine was feathered; an emergency declared; and a safe single engine landing ensued.