A PIPER WARRIOR PLT LANDED OFF ARPT.

Narrative

THE PROB AROSE FROM A LEAKING FUEL DRAIN ON THE ENG FUEL SUMP. POSSIBLE FACTORS CAUSING THE PROB ARE: A WEAK SPRING IN THE FUEL DRAIN; A PIECE OF DEBRIS IN THE FUEL DRAIN; POSSIBLY NOT CHKING TO MAKE SURE THE FUEL HAD STOPPED DRAINING. THE PROB WAS DISCOVERED UPON LNDG. FUEL WAS DRAINING FROM THE ENG FUEL SUMP DRAIN. THIS APPARENTLY INTRODUCED AIR INTO THE FUEL SYS CAUSING THE PARTIAL PWR CONDITION. THE CORRECTIVE ACTION WAS TO POKE THE FUEL DRAIN TWICE AND IT QUIT DRAINING FUEL. PREFLT: PREFLT WAS NORMAL AND WAS DONE WITH THE PREFLT CHKLIST IN HAND. AT THE TIME THE ENG FUEL SUMP DRAIN WAS CHKED; IT APPEARED TO BE NORMAL. THE NOSE SECTION OF THE CHKLIST WAS THEN READ BY ME; WHILE STANDING IN FRONT OF THE FUEL DRAIN. AT HIS POINT A DOUBLE CHK ON THE FUEL DRAIN WAS NOT MADE. IN THEN PROCEEDED TO PREFLT THE REST OF ACFT AND FOUND NOTHING OUT OF ORDER. I PROCEEDED INTO THE CABIN OF THE AIRPLANE AND ORGANIZED MY EQUIP AND SET UP THE RADIOS. I THEN FOLLOWED THE ENG STARTING CHKLIST. ENG START WAS NORMAL. TAXI: TAXI TO THE RUN-UP AREA WAS NORMAL. NOTE: TAXI WAS MADE WITH ELECTRIC FUEL PUMP OFF AS PER MY REGULAR HABIT; SO AS TO TEST THE MECHANICAL FUEL PUMP ON THE ENG; NO PROBS DETECTED. RUN-UP: RUN-UP WAS DONE AS PER THE PA28-161 CHKLIST. EVERYTHING WAS FOUND TO BE IN ORDER. NOTE: ELECTRIC FUEL PUMP WAS TURNED BACK ON AT THE END OF THE RUN-UP AS PER CHKLIST. AFTER USING 'LIGHTS; CAMERA (XPONDER); ACTION (MIXTURE RICH; THROTTLE FULL FORWARD);' I PROCEEDED WITH THE TKOF ROLL. EVERYTHING WAS OPERATING NORMALLY AND I ROTATED AT 60 KTS. AT THE APPROX 250 AGL; I EXPERIENCED A PARTIAL LOSS OF PWR. I IMMEDIATELY PUT CARB HEAT ON AN CHKED MIXTURE RICH (IT WAS); FUEL PUMP ON (IT WAS); PRIMER IN AND LOCKED (IT WAS); AND SWITCHED FROM L TANK TO R FUEL TANK. FULL PWR WAS RESTORED. I TURNED L 120 DEG AND EXPERIENCED ANOTHER PARTIAL PWR LOSS. AFTER GOING THROUGH THIS PROC AGAIN AND; IN ADDITION; LEAVING THE THROTTLE AT 25 PERCENT TO 30 PERCENT; WHICH I WAS ABLE TO SUSTAIN; I INFORMED THE CTAF (124.60) THAT I HAD ENG TROUBLE. AT THIS POINT; I FELT THAT IT WAS NOT SAFE TO DRAG THE ACFT TO THE ARPT AT SUCH A LOW PWR SETTING. AS THERE WERE NO WIRES OR INTERFERING TFC ON MCKELLIPS RD; I IMPLEMENTED A PRECAUTIONARY LNDG. AFTER LNDG; I TAXIED INTO A PARKING LOT; SECURED THE ACFT AND DEPLANED. UPON AN EXTERNAL EXAMINATION OF THE PLANE; I DISCOVERED FUEL COMING FROM THE ENG FUEL SUMP DRAIN. I POKED IT TWICE AND IT SEATED; CAUSING THE FUEL FLOW STOP. EVERYTHING CHKED OUT SAFETY WISE AS FAR AS TAXIING THE AIRPLANE; SO I ASKED FOR AND RECEIVED A POLICE AND FIRE ESCORT BACK TO FALCON FIELD ARPT; APPROX ONE MI.