Narrative:

Flying on a filed flight plan to ZZZ. I first noticed blue streaking aft of the main tank on the right about 15 mins after flight. The fuel indicator remained full at all times; even before switching later in the flight. While diverting for a restroom break to ZZZ2; I was on the GPS approach established on final with about 4 mi to go in IMC. The autoplt was on; and I had switched to the main tanks as on the checklist. I then noticed a sudden turn to the left on the heading indicator. I disengaged the autoplt and noticed the right engine has stopped. I feathered immediately being so close to the ground to go missed and notified approach of right engine out and declared an emergency. Troubleshooting for the next few mins at a higher altitude led me to believe the right main tank was empty. I was able to switch back to the auxiliary tank and restart the engine and eventually land at ZZZ on an ILS approach. Upon inspection on the ramp; the right main fuel cap was ever so slightly displaced. The bladder was empty. Fueler had filled 111 gallons into the plane. I should have only used approximately 60-70 gallons. I ran the engine on the ground for several mins after the tank was full at high power settings with no problems and felt the empty tank due to leaking was the cause. I imagine that some type of venturi effect led to the fuel reading on the gauge which later showed an accurate reading on the next leg of the trip. I had received a fill up prior to my departure and knew that I had full tanks. The ultimate cause was the fuel cap which was secured tightly but not correctly.

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Original NASA ASRS Text

Title: BE55 PLT EXPERIENCES FUEL EXHAUSTION IN HIS RIGHT MAIN TANK AND A SUBSEQUENT ENGINE FAILURE. TROUBLESHOOTING ALLOWED HIM TO RESTART ON THE AUX TANK AND LAND SAFELY. AN EMERGENCY WAS DECLARED.

Narrative: FLYING ON A FILED FLT PLAN TO ZZZ. I FIRST NOTICED BLUE STREAKING AFT OF THE MAIN TANK ON THE R ABOUT 15 MINS AFTER FLT. THE FUEL INDICATOR REMAINED FULL AT ALL TIMES; EVEN BEFORE SWITCHING LATER IN THE FLT. WHILE DIVERTING FOR A RESTROOM BREAK TO ZZZ2; I WAS ON THE GPS APCH ESTABLISHED ON FINAL WITH ABOUT 4 MI TO GO IN IMC. THE AUTOPLT WAS ON; AND I HAD SWITCHED TO THE MAIN TANKS AS ON THE CHKLIST. I THEN NOTICED A SUDDEN TURN TO THE L ON THE HDG INDICATOR. I DISENGAGED THE AUTOPLT AND NOTICED THE R ENG HAS STOPPED. I FEATHERED IMMEDIATELY BEING SO CLOSE TO THE GND TO GO MISSED AND NOTIFIED APCH OF R ENG OUT AND DECLARED AN EMER. TROUBLESHOOTING FOR THE NEXT FEW MINS AT A HIGHER ALT LED ME TO BELIEVE THE R MAIN TANK WAS EMPTY. I WAS ABLE TO SWITCH BACK TO THE AUX TANK AND RESTART THE ENG AND EVENTUALLY LAND AT ZZZ ON AN ILS APCH. UPON INSPECTION ON THE RAMP; THE R MAIN FUEL CAP WAS EVER SO SLIGHTLY DISPLACED. THE BLADDER WAS EMPTY. FUELER HAD FILLED 111 GALLONS INTO THE PLANE. I SHOULD HAVE ONLY USED APPROX 60-70 GALLONS. I RAN THE ENG ON THE GND FOR SEVERAL MINS AFTER THE TANK WAS FULL AT HIGH PWR SETTINGS WITH NO PROBS AND FELT THE EMPTY TANK DUE TO LEAKING WAS THE CAUSE. I IMAGINE THAT SOME TYPE OF VENTURI EFFECT LED TO THE FUEL READING ON THE GAUGE WHICH LATER SHOWED AN ACCURATE READING ON THE NEXT LEG OF THE TRIP. I HAD RECEIVED A FILL UP PRIOR TO MY DEP AND KNEW THAT I HAD FULL TANKS. THE ULTIMATE CAUSE WAS THE FUEL CAP WHICH WAS SECURED TIGHTLY BUT NOT CORRECTLY.

Data retrieved from NASA's ASRS site as of May 2009 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.