Narrative:

Flight was uneventful from hfd to descent into hef. At 3000 ft MSL, right engine failed. I performed 'engine out' procedure while my passenger (also pilot) declared emergency with dulles approach. I immediately recognized that fuel selector switches were in 'auxiliary tank' and therefore switched right to 'main.' the engine immediately came back on. As I switched left from auxiliary to main, it quit, then came back on. Aircraft lost 300 ft during emergency. We told dulles we were ok, they vectored us for landing at hef and the remainder of trip was routine. Dulles did not request (nor did tower acknowledge our previous situation) any follow-up. I dropped my passenger at hef and flew on to jyo with no problem. On refueling the auxiliary tanks I noted the following: 166 gallons on departure, 33 gallons in each auxiliary tank. Left tank = 30.0, usable remaining = 1 1/2 gallons. Right tank = 31.0, usable remaining = 1/2 gallon. The auxiliary tanks contain 31 1/2 gallons usable and that should be about 2 hours flying time. I had flown on auxiliary setting for 1 hour 15 mins. Plane is a new purchase and I must calibrate more precisely fuel flow from auxiliary tanks. Fuel flow indicated 90 pounds/hour or 15 gallons. I checked tanks on preflight. I must actually be present on filling to ensure full tanks in future. However, when I opened gas tank caps, fuel came out, so I believe they were full and I must have burned fuel richer than indicated on gauge. Callback conversation with reporter revealed the following information: reporter stated that he did not realize that the auxiliary tank excess fuel was returned to the mains and that the mains could vent fuel overboard during the auxiliary tank use if the main tank fuel was not used for approximately 45 mins prior to using all the auxiliary tank fuel.

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Original NASA ASRS Text

Title: PLT OF A C310 EXPERIENCED ENG FUEL STARVATION FOR A BRIEF TIME DURING A NIGHT ARR 8 MI FROM THE ARPT AND DECLARED AN EMER UNTIL BOTH ENGS RECOVERED AFTER THE MAIN FUEL TANKS WERE SELECTED. THE AUX FUEL TANKS WERE EMPTY OF USABLE FUEL.

Narrative: FLT WAS UNEVENTFUL FROM HFD TO DSCNT INTO HEF. AT 3000 FT MSL, R ENG FAILED. I PERFORMED 'ENG OUT' PROC WHILE MY PAX (ALSO PLT) DECLARED EMER WITH DULLES APCH. I IMMEDIATELY RECOGNIZED THAT FUEL SELECTOR SWITCHES WERE IN 'AUX TANK' AND THEREFORE SWITCHED R TO 'MAIN.' THE ENG IMMEDIATELY CAME BACK ON. AS I SWITCHED L FROM AUX TO MAIN, IT QUIT, THEN CAME BACK ON. ACFT LOST 300 FT DURING EMER. WE TOLD DULLES WE WERE OK, THEY VECTORED US FOR LNDG AT HEF AND THE REMAINDER OF TRIP WAS ROUTINE. DULLES DID NOT REQUEST (NOR DID TWR ACKNOWLEDGE OUR PREVIOUS SIT) ANY FOLLOW-UP. I DROPPED MY PAX AT HEF AND FLEW ON TO JYO WITH NO PROB. ON REFUELING THE AUX TANKS I NOTED THE FOLLOWING: 166 GALLONS ON DEP, 33 GALLONS IN EACH AUX TANK. L TANK = 30.0, USABLE REMAINING = 1 1/2 GALLONS. R TANK = 31.0, USABLE REMAINING = 1/2 GALLON. THE AUX TANKS CONTAIN 31 1/2 GALLONS USABLE AND THAT SHOULD BE ABOUT 2 HRS FLYING TIME. I HAD FLOWN ON AUX SETTING FOR 1 HR 15 MINS. PLANE IS A NEW PURCHASE AND I MUST CALIBRATE MORE PRECISELY FUEL FLOW FROM AUX TANKS. FUEL FLOW INDICATED 90 LBS/HR OR 15 GALLONS. I CHKED TANKS ON PREFLT. I MUST ACTUALLY BE PRESENT ON FILLING TO ENSURE FULL TANKS IN FUTURE. HOWEVER, WHEN I OPENED GAS TANK CAPS, FUEL CAME OUT, SO I BELIEVE THEY WERE FULL AND I MUST HAVE BURNED FUEL RICHER THAN INDICATED ON GAUGE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED THAT HE DID NOT REALIZE THAT THE AUX TANK EXCESS FUEL WAS RETURNED TO THE MAINS AND THAT THE MAINS COULD VENT FUEL OVERBOARD DURING THE AUX TANK USE IF THE MAIN TANK FUEL WAS NOT USED FOR APPROX 45 MINS PRIOR TO USING ALL THE AUX TANK FUEL.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.