ROUGH ENGINE RUN ON FINAL FOLLOWING A LONG CROSS COUNTRY ALERTS INEXPERIENCED PRIVATE PLT TO NEAR FUEL EXHAUSTION. DISCOVERS ONLY THREE GALLONS OF FUEL LEFT IN THE C172 AFTER REFUELING.

Narrative

AS I WAS DSNDING TO TPA AFTER XCOUNTRY; I DSNDED IN STEPS FROM 9500 FT. FROM 5500 FT TO 2800 FT I DSNDED RATHER STEEPLY TO GET TO TPA BEFORE I STARTED THE 3 MI 45 DEGS. AS I ROUNDED OUT FROM THE DSCNT THE ENG STARTED TO MISS. A STEADY DUM; DUM; DUM; LIKE A FOULED PLUG; OR LOOSE PLUG WIRE OR PERHAPS A MAG; I APPLIED THROTTLE AND IT TOOK THE THROTTLE SMOOTHLY WITH NO HESITATION OR SPUTTER; BUT IT STILL HAD THE STEADY MISS. IT WOULD TAKE FULL PWR AND ACCELERATE WITH NO HESITATION. I ENTERED THE PATTERN AND LANDED. AFTER TAXIING TO THE TIE-DOWNS AND DURING MAG GND CHK; I SHUT DOWN. THE BRIEFING HAD CALLED FOR 20 KT HEADWINDS BUT DURING THE LATER PART OF THE FLT MY CHK POINTS WERE LATE. I RECALCULATED THE TIME AND FUEL AND FELT I HAD ENOUGH. AFTER FILLING THE TANKS (47 GALS/50 GAL TANK) I SAID THAT AS I ARRIVED AT THE FIELD I HAD HAD APPROX 30 MINS OF FUEL. THE CHIEF FLT INSTRUCTOR; WHO HAD GIVEN ME MY CHK RIDE AND PROGRESSIVE CHKS WHEN I WAS A STUDENT SAID I SHOULD HAVE USED EVEN MORE CONSERVATIVE MILEAGE FIGURES TO PLAN THAN I DID. I TOLD HIM THAT NEITHER HE NOR THE INSTRUCTOR HAD EVER MENTIONED FIGURES OTHER THAN THE POH NUMBERS. IT WOULD BE A GOOD IDEA FOR INSTRUCTORS TO TELL STUDENTS AND NEW PLTS THAT THE PLANES DON'T GET THE GPH OR TAS LISTED; ESPECIALLY THE OLDER PLANES.