Narrative:

The fuel truck was broken. Instead of paying very high fuel prices; the decision was made to fly to ZZZ to refuel before flying to ZZZ1. After looking at the flight plan numbers and WX; it was determined the fuel reserve was met to ZZZ and the WX forecast did not call for an alternate. After becoming airborne it was found that the forecasted crosswind was more of a headwind. As you got closer to ZZZ the headwind was getting stronger. When the switch was made to ZZZ approach; they said there was a thunderstorm cell between me and the airport and that vectoring around it was required to stay safe. The fuel gauge was indicating there was only a little more than reserve fuel left. Also; the thunderstorm has made ZZZ MVFR. The decision was made to divert to ZZZ2. ZZZ2 was reporting VFR conditions. About 20 NM from ZZZ2 the fuel gauge showed less than 20 mins of fuel on board. There was a headwind to ZZZ2; the airport was not in sight. The flight conditions were VFR. An emergency was declared with center. After landing safely; the airplane was refueled by top-off. After refueling the aircraft; it was found that there was 1.1 hours of fuel still on board. Then after looking at the flight times from the flight before; they both matched up at 1.1 hours left on board. In conclusion; fuel could have been bought at the other FBO prior to departure. And there was too much trust put in the fuel gauge and not enough put into dead reckoning. The fuel gauge was found to be indicating about 1 hour lower than what was on the aircraft after landing in ZZZ2.

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Original NASA ASRS Text

Title: AERO COMMANDER PILOT DEPARTS WITHOUT REFUELING; WINDS AND WEATHER ENROUTE REQUIRE DIVERSION AND DECLARATION OF FUEL EMERGENCY.

Narrative: THE FUEL TRUCK WAS BROKEN. INSTEAD OF PAYING VERY HIGH FUEL PRICES; THE DECISION WAS MADE TO FLY TO ZZZ TO REFUEL BEFORE FLYING TO ZZZ1. AFTER LOOKING AT THE FLT PLAN NUMBERS AND WX; IT WAS DETERMINED THE FUEL RESERVE WAS MET TO ZZZ AND THE WX FORECAST DID NOT CALL FOR AN ALTERNATE. AFTER BECOMING AIRBORNE IT WAS FOUND THAT THE FORECASTED XWIND WAS MORE OF A HEADWIND. AS YOU GOT CLOSER TO ZZZ THE HEADWIND WAS GETTING STRONGER. WHEN THE SWITCH WAS MADE TO ZZZ APCH; THEY SAID THERE WAS A TSTM CELL BTWN ME AND THE ARPT AND THAT VECTORING AROUND IT WAS REQUIRED TO STAY SAFE. THE FUEL GAUGE WAS INDICATING THERE WAS ONLY A LITTLE MORE THAN RESERVE FUEL LEFT. ALSO; THE TSTM HAS MADE ZZZ MVFR. THE DECISION WAS MADE TO DIVERT TO ZZZ2. ZZZ2 WAS RPTING VFR CONDITIONS. ABOUT 20 NM FROM ZZZ2 THE FUEL GAUGE SHOWED LESS THAN 20 MINS OF FUEL ON BOARD. THERE WAS A HEADWIND TO ZZZ2; THE ARPT WAS NOT IN SIGHT. THE FLT CONDITIONS WERE VFR. AN EMER WAS DECLARED WITH CTR. AFTER LNDG SAFELY; THE AIRPLANE WAS REFUELED BY TOP-OFF. AFTER REFUELING THE ACFT; IT WAS FOUND THAT THERE WAS 1.1 HRS OF FUEL STILL ON BOARD. THEN AFTER LOOKING AT THE FLT TIMES FROM THE FLT BEFORE; THEY BOTH MATCHED UP AT 1.1 HRS LEFT ON BOARD. IN CONCLUSION; FUEL COULD HAVE BEEN BOUGHT AT THE OTHER FBO PRIOR TO DEP. AND THERE WAS TOO MUCH TRUST PUT IN THE FUEL GAUGE AND NOT ENOUGH PUT INTO DEAD RECKONING. THE FUEL GAUGE WAS FOUND TO BE INDICATING ABOUT 1 HR LOWER THAN WHAT WAS ON THE ACFT AFTER LNDG IN ZZZ2.

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.