LOW TIME SMA PLT; CONCERNED OVER FLUCTUATING FUEL GAUGES; ADVISES TRACON APCH CTLR OF SITUATION AND REQUESTS MOST EXPEDITIOUS RTE TO DEST ARPT. CTLR; CONCERNED OVER FACTS; DECLARES AN EMER SITUATION FOR PLT AT DEST ARPT.

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THIS EVENT OCCURRED AT THE END OF AN IFR FLT FROM RDU TO BDR. ACCORDING TO CONSERVATIVE FLT PLAN CALCULATIONS; THE FLT SHOULD TAKE 3 HRS AND 30 MINS; CONSUME 38 GALLONS; AND THE FUEL ON BOARD (FULL TANKS -- 49 GALLONS USABLE) WAS 4 HRS AND 30 MINS. THE WX AT THE DEST WAS VFR AND NO ALTERNATE WAS REQUIRED. THE FLT PROCEEDED NORMALLY EXCEPT FOR SOME DEVS AROUND WX AND MODERATE (OCCASIONALLY SEVERE) TURB DURING THE FIRST HR OF FLT. AFTER ABOUT 3 HRS OF FLT; AS THE FLT APCHED JFK; AND THE FUEL LEVEL GOT LOWER; THE FUEL GAUGES INDICATIONS BECAME ERRATIC. THE INDICATOR NEEDLES WOULD SWING WILDLY FROM NEAR EMPTY TO ALMOST FULL. AN ATTEMPT TO GET A READING FROM THE FUEL GAUGES INDICATED THAT THERE MIGHT BE AS LITTLE AS 12 GALLONS OF FUEL LEFT (BOTH TANKS); WHICH WOULD BE ENOUGH FOR ABOUT AN HR OF FULL CRUISE PWR. AT THAT TIME THE FLT WAS ABOUT 35 MINS FROM BDR. PROPER LEANING AND PWR SETTINGS HAD BEEN USED FOR THE ENTIRE FLT; AND FLT TIME; GND SPD AND FUEL FLOW INDICATIONS WERE ACCORDING TO PLAN (OR BETTER) UP TO THAT TIME. BASED ON THE MORE ACCURATE CALCULATIONS CONSERVATIVELY USING THE POH FIGURES AND ACTUAL FLT DATA; THE TANKS STILL HAD 1 HR AND 40 MINS OF FUEL REMAINING. BASED ON THE 2 CONFLICTING INFO; AND EVEN THOUGH I GENERALLY DON'T RELY ON FUEL GAUGE INDICATIONS ON SINGLE ENG SMA AIRPLANES; I DECIDED TO INFORM ATC (NY APCH) OF THE POSSIBLE FUEL SITUATION. SO I TOLD ATC THAT I ESTIMATED FUEL REMAINING AT 55 MINS; AND THAT I WOULD APPRECIATE THE MOST DIRECT RTE TO BDR. THE CTLR ACKNOWLEDGE AND SAID I COULD FLY DIRECT TO BDR IF I DIDN'T MIND THE LONGER OVERWATER DISTANCE. I ACCEPTED AND PROCEEDED DIRECT TO BDR. OBVIOUSLY; IN THE CONGESTED NY APCH FREQS; IT IS IMPOSSIBLE TO INFORM ATC OF ALL THE DETAILS; AND HOW I ARRIVED AT THE FUEL ESTIMATE. SO ONLY THE WORST CASE FUEL ESTIMATE WAS GIVEN TO ATC. AT NO TIME I DECLARED OR THOUGHT OF THIS AS AN EMER; SINCE EVEN WITH THE MOST PESSIMISTIC FUEL GAUGE INDICATIONS I'D STILL HAVE 25 MINS OF FUEL WHEN I LANDED AT BDR -- MOST LIKELY MORE THAN AN HR BASED ON THE MORE RELIABLE FUEL CALCULATIONS. ALSO WX WAS VFR FOR THE ENTIRE AREA AND NO DELAYS WERE EXPECTED. I TOLD ATC OF THE SITUATION BECAUSE I THOUGHT IT WAS RELEVANT; AND I MIGHT HAVE HAD TO REQUEST PRIORITY IF ATC DELAYS OR RTE CHANGES SIGNIFICANTLY DELAYED THE FLT. THE FLT WAS COMPLETED AS PLANNED. I LANDED AT BDR 3 HRS AND 40 MINS AFTER DEPARTING RDU. IMMEDIATELY AFTER PARKING I REQUESTED REFUELING; AND TOPPING OFF BOTH TANKS REQUIRED 37.8 GALLONS; MEANING THAT 11.2 GALLONS OF USABLE FUEL (ABOUT AN HR AT FULL CRUISE PWR) WERE STILL AVAILABLE AT THE END OF THE FLT. THESE FIGURES ARE REMARKABLY CLOSE TO THE FLT PLANNING; AND PROVE THE FUEL GAUGES WERE IN FACT INACCURATE. UNFORTUNATELY; ATC; WITHOUT MY REQUEST OR KNOWLEDGE; HAD DECLARED AN EMER FOR MY LNDG AT BDR. WHEN I SWITCHED FROM APCH TO TWR FREQ; I FIRST HEARD THE BDR TWR TELLING ANOTHER PLT THAT THEY HAD AN EMER LNDG AND THAT THE ARPT MIGHT BE CLOSED FOR A FEW MINS. SO; ON MY INITIAL CONTACT WITH THE TWR I INFORMED THEM THAT I HAD 25 MINS OF FUEL ON BOARD; THINKING THAT; IF THE EMER WAS ME; THAT WOULD BE ENOUGH TO DISCONTINUE IT. BDR TWR ACKNOWLEDGED AND GAVE ME MY PATTERN ENTRY INSTRUCTIONS. ANOTHER ACFT WAS THEN TOLD THAT THE ARPT WAS CLOSED. STILL NOT SURE IF THE EMER WAS MY FLT; I INQUIRED THE TWR IF THE ARPT WAS CLOSED FOR ME; AND I WAS TOLD IT WAS NOT. I GOT MY CLRNC TO LAND; AND WAS SURPRISED TO BE FOLLOWED TO THE RAMP BY RESCUE VEHICLES. OBVIOUSLY; NO EMER EXISTED; AND TO THE EXTENT THAT MY WORST CASE FUEL ESTIMATE TRIGGERED THE PROCS; I FEEL SORRY FOR THOSE I MIGHT HAVE UNNECESSARILY INCONVENIENCED. I BELIEVE THAT 2 THINGS COULD HAVE PREVENTED THIS UNNECESSARY EMER FROM BEING DECLARED: 1) IF I HAD BEEN FAMILIAR WITH THE BEHAVIOR OF THE FUEL GAUGES WITH LESS THAN HALF-FULL TANKS ON THAT AIRPLANE; I'D BE MORE CONFIDENT TO DISREGARD THE FUEL GAUGES AND RELY SOLEY ON MY FUEL CALCULATIONS. 2) SINCE IT IS VIRTUALLY IMPOSSIBLE FOR A PLT TO INFORM ATC OF ALL THE ASPECTS INVOLVEDIN COCKPIT COMPUTATIONS; ANALYSIS AND DECISIONS; ATC SHOULD NOT UNILATERALLY; AND WITHOUT CONSULTING THE PIC; DECLARE AN EMER ON BEHALF OF THE PLT IN A SITUATION SUCH AS THIS. I APPRECIATE THE FACT THAT SOME PLTS MAY GET IN TROUBLE BECAUSE THEY ARE RELUCTANT TO DECLARE AN EMER. HOWEVER I BELIEVE; MOST PLTS PUT SAFETY FIRST; AND WOULD NOT HESITATE TO DECLARE AN EMER WHEN NEEDED. THEREFORE; I THINK ATC SHOULD CHK (IF POSSIBLE) WITH PLTS BEFORE DECLARING AN EMER ON THEIR BEHALF. AFTER ALL; IF I'M TAKING THE EXTRA STEP OF KEEPING ATC INFORMED OF A POTENTIAL FUEL SITUATION; I'D OBVIOUSLY NOT HESITATE TO DECLARE AN EMER AND REQUEST PRIORITY HANDLING IF NEEDED.