A PA28 PLT MADE AN OFF FIELD LNDG FOLLOWING FUEL EXHAUSTION BECAUSE THE ENG WAS NOT LEANED ADEQUATELY AND SO FUEL USAGE WAS HIGHER THAN EXPECTED.

Narrative

WHILE ON A 6.5 MI FINAL APCH TO LAND AT ZZZ3; THE PIPER ARCHER; OF WHICH I WAS PIC; SUFFERED A PWR LOSS AND SUBSEQUENTLY I WAS FORCED TO LAND OFF ARPT. THERE WERE NO INJURIES OR PROPERTY DAMAGE AND THE ONLY DAMAGE TO THE ACFT WAS A BROKEN POS LIGHT ON THE L WINGTIP. THE CAUSE OF THE PWR LOSS WAS DETERMINED TO BE FUEL EXHAUSTION. I BELIEVE THE CAUSE OF THE FUEL EXHAUSTION WAS A COMBINATION OF IMPROPER LEANING PROCS THAT LED TO EXCESSIVE FUEL CONSUMPTION IN COMBINATION WITH A GROSSLY INACCURATE L FUEL GAUGE WHICH LED ME TO BELIEVE I HAD ENOUGH FUEL TO LAND AT ZZZ3 WITH LEGAL FUEL RESERVES. I DEPARTED ZZZ1 WITH 1 PVT PLT/PAX. WE FLEW TO ZZZ2 TO PICK UP 2 PAX FOR CHARITABLE MEDICAL AIR TRANSPORTATION. I USE DUATS FLT PLANNER AND HAVE THE FUEL BURN SET FOR 9.5 GPH. THE FLT PLANNER CALCULATED THE FLT FROM ZZZ2 TO ZZZ3 TO TAKE 2 HRS 42 MINS AND REQUIRE 26 GALLONS OF FUEL. GOOD VMC WAS FORECAST AT ZZZ2 FOR MY TIME OF ARR AND I DECIDED I COULD DEPART WITH THE FUEL THAT WAS ON BOARD AND STILL LAND WITH 1 HR OF FUEL REMAINING. THIS WAS MY FIRST MISSED OPPORTUNITY TO BREAK THE CHAIN OF EVENTS THAT LED TO FUEL EXHAUSTION. WHEN I SAW THAT I HAD LESS FUEL IN THE TANKS THAN EXPECTED; I SHOULD HAVE ORDERED MORE FUEL. I ALSO SHOULD HAVE GIVEN SOME THOUGHT AS TO WHY I DIDN'T HAVE AS MUCH FUEL AS EXPECTED AFTER TAKING ON THE 10 GALLONS AS PLANNED. DURING THE ACFT'S RECENT ANNUAL INSPECTION; A CYLINDER HAD TO BE REPLACED AND THE MECH STATED THAT IT APPEARED TO BE DAMAGED FROM OVER-LEANING. HE ADVISED THE FLYING CLUB'S BOARD OF DIRECTORS THAT PLTS NEEDED TO BE CAREFUL NOT TO OVER-LEAN THE ENG. I TOOK HIS ADVICE OUT OF CONTEXT AND LEANED TO A SETTING RELATIVELY RICH COMPARED TO THE NORMAL 50 DEGS RICH OF PEAK EGT SETTING THAT I HAVE ALWAYS USED IN THE PAST. WHILE I SHOULD HAVE REALIZED THE FUEL BURN CALCULATIONS I USE DURING PREFLT PLANNING WOULD NOT BE ACCURATE IF I DIDN'T USE THE SAME RECOMMENDED LEANING PROCS I HAD ALWAYS USED IN THE PAST; I NEVER WOULD HAVE GUESSED THE DIFFERENCE IN FUEL CONSUMPTION WOULD BE 3 GPH AS IT TURNED OUT TO BE. I HAD DEPARTED ZZZ2 ON THE L FUEL TANK. I SET A TIMER FOR 1 HR AND SWITCHED TO THE R TANK WHEN THE TIMER WENT OFF. I SET THE TIMER TO 1 HR 30 MINS FOR THE R TANK. WITH 3 MINS REMAINING ON THE TIMER; THE R FUEL TANK RAN OUT OF FUEL. I SWITCHED TO THE L TANK IMMEDIATELY. THE R TANK SHOULD HAVE HAD 25-30 MINS OF FUEL REMAINING AT THE TIME THE TANK RAN DRY. AFTER SWITCHING TO THE L TANK; I CHKED THE GAUGE AND IT SHOWED 15 GALLONS REMAINING. I ESTIMATED I WOULD LAND WITH 1 HR OF FUEL REMAINING AS EXPECTED. THE PLT/PAX SITTING IN THE R FRONT SEAT STATED HE TOO SAW THAT THE GAUGE WAS READING 15 GALLONS REMAINING ON THE L TANK. AT THIS TIME; I SHOULD HAVE RECOGNIZED THAT THE GAUGE COULDN'T POSSIBLY BE CORRECT. HAD I REALIZED THAT I COULDN'T POSSIBLY HAVE 15 GALLONS REMAINING IN THE L TANK; I WOULD HAVE DIVERTED TO NEARBY ZZZ4 FOR FUEL. THIS; OF COURSE; WAS ANOTHER LINK IN THE CHAIN OF EVENTS THAT COULD HAVE BEEN BROKEN. APPROX 30 MINS LATER; WHILE ON THE LAST VECTOR TO INTERCEPT THE LOC FOR RWY 16 (CIRCLE TO LAND RWY 30); THE ENG BEGAN LOSING PWR. I WAS AT 2500 FT MSL AND APPROX 6.5 MI FROM ZZZ3. I DECLARED AN EMER AND ADVISED THE CTLR THAT I COULDN'T MAINTAIN ALT AND WAS LOOKING FOR A PLACE TO LAND. I IMMEDIATELY LOOKED AT THE L FUEL GAUGE AND IT SHOWED IT HAD 10 GALLONS OF FUEL REMAINING. I BRIEFLY BEGAN TROUBLESHOOTING INCLUDING CARB HEAT; L FUEL TANK SELECTED; MIXTURE AND THROTTLE FORWARD. I WAS IN A POPULATED AREA AND QUICKLY ABANDONED THE EFFORT TO RESTORE PWR SO I COULD FLY THE PLANE AND FIND A PLACE TO LAND. I LANDED ON A NEW ROAD ADJACENT TO A SUBDIVISION THAT HAD NOT YET BEEN OPENED AND WAS BARRICADED AT THE FAR END. THERE WAS NO EVIDENCE OF A FUEL LEAK TO EXPLAIN THE HIGH RATE OF FUEL CONSUMPTION. THE ACFT WAS DISMANTLED AND TRAILERED BACK TO ZZZ3 FOR REASSEMBLY. IN HINDSIGHT; WHEN THE TANK RAN DRY UNEXPECTEDLY WHEN IT SHOULD HAVE HAD 30 MINS OF FUEL AVAILABLE; I SHOULD HAVE DIVERTED ANYWAY. I HAD NEVER RUN ANY FUEL TANK DRY IN THE 13 YRS I'VE BEEN FLYING PRIOR TO THIS FLT. FORTUNATELY; NOBODY WAS HURT.