Narrative:

C172, 180 hp, departed bkt, va, approximately XA00 with 3 pilots on board -- 2 with over 1000 hours, the PF (left seat) has approximately 500 hours. Right seater is instructor (your reporter). Back seater checked fuel, reported full (both tanks combined have 40 gallons usable). In preflight planning, we knew we had 40 KT headwind, estimated 3.5 hours flying time, would use 10 gallons fuel per hour, with 30 mins fuel remaining. Right seater suggested a rest/fuel stop at SOP, nc. PF said he wanted to get back quickly and did not see any need to stop at SOP, nc. Wind at cae (destination) out of southwest gusting to 24 KTS. PF cruised at 2600 RPM at 6000 ft MSL. A call came from a company plane saying they had landed in flo for fuel, taking on 31 gallons. We acknowledged the call and continued on toward the destination. The fuel gauges read, left tank 1/2 full, right tank nearing empty. At cae we were cleared for the approach to runway 5 visual. Our left tank was still 1/2 full (showing) with right tank appearing to be on empty. We landed at cae. At refueling, we took on 37.5 gallons, meaning we only had 2.50 gallons of fuel remaining. If the aircraft were full (40 gallons, usable), we burned 11.36 gph. Endurance charts show a burn of 10.1 gph at 6000 ft at 2600 RPM. I don't think any of the 3 of us were surprised. The PF said 'there's got to be something wrong with this airplane.' I told him he shouldn't trust the endurance charts. On refueling, we found that we had 1.25 gallons per tank -- even though the left tank still showed 1/2 full when we stopped the engine on the ramp. I found that contrary to my own teaching, I was hoping that the left gauge was accurately reading fuel remaining. But I had a terrible feeling that the gauge was wrong, but I didn't know how wrong.

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Original NASA ASRS Text

Title: AN INSTRUCTOR ALONG WITH 2 OTHER PLTS, AFTER A XCOUNTRY FLT, LANDED WITH ONLY 2 PT 5 GALLONS OF FUEL REMAINING.

Narrative: C172, 180 HP, DEPARTED BKT, VA, APPROX XA00 WITH 3 PLTS ON BOARD -- 2 WITH OVER 1000 HRS, THE PF (L SEAT) HAS APPROX 500 HRS. R SEATER IS INSTRUCTOR (YOUR RPTR). BACK SEATER CHKED FUEL, RPTED FULL (BOTH TANKS COMBINED HAVE 40 GALLONS USABLE). IN PREFLT PLANNING, WE KNEW WE HAD 40 KT HEADWIND, ESTIMATED 3.5 HRS FLYING TIME, WOULD USE 10 GALLONS FUEL PER HR, WITH 30 MINS FUEL REMAINING. R SEATER SUGGESTED A REST/FUEL STOP AT SOP, NC. PF SAID HE WANTED TO GET BACK QUICKLY AND DID NOT SEE ANY NEED TO STOP AT SOP, NC. WIND AT CAE (DEST) OUT OF SW GUSTING TO 24 KTS. PF CRUISED AT 2600 RPM AT 6000 FT MSL. A CALL CAME FROM A COMPANY PLANE SAYING THEY HAD LANDED IN FLO FOR FUEL, TAKING ON 31 GALLONS. WE ACKNOWLEDGED THE CALL AND CONTINUED ON TOWARD THE DEST. THE FUEL GAUGES READ, L TANK 1/2 FULL, R TANK NEARING EMPTY. AT CAE WE WERE CLRED FOR THE APCH TO RWY 5 VISUAL. OUR L TANK WAS STILL 1/2 FULL (SHOWING) WITH R TANK APPEARING TO BE ON EMPTY. WE LANDED AT CAE. AT REFUELING, WE TOOK ON 37.5 GALLONS, MEANING WE ONLY HAD 2.50 GALLONS OF FUEL REMAINING. IF THE ACFT WERE FULL (40 GALLONS, USABLE), WE BURNED 11.36 GPH. ENDURANCE CHARTS SHOW A BURN OF 10.1 GPH AT 6000 FT AT 2600 RPM. I DON'T THINK ANY OF THE 3 OF US WERE SURPRISED. THE PF SAID 'THERE'S GOT TO BE SOMETHING WRONG WITH THIS AIRPLANE.' I TOLD HIM HE SHOULDN'T TRUST THE ENDURANCE CHARTS. ON REFUELING, WE FOUND THAT WE HAD 1.25 GALLONS PER TANK -- EVEN THOUGH THE L TANK STILL SHOWED 1/2 FULL WHEN WE STOPPED THE ENG ON THE RAMP. I FOUND THAT CONTRARY TO MY OWN TEACHING, I WAS HOPING THAT THE L GAUGE WAS ACCURATELY READING FUEL REMAINING. BUT I HAD A TERRIBLE FEELING THAT THE GAUGE WAS WRONG, BUT I DIDN'T KNOW HOW WRONG.

Data retrieved from NASA's ASRS site as of July 2007 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.