Narrative:

I had just listened to ATIS and called bis approach. The engine began to run rough. Fuel pressure was not steady. I advised bis approach I was going to land and that I would call them when down. I immediately selected an isolated road and landed with some power. I did not declare an emergency. After landing and inspecting the tanks visually, I went to a telephone and called the bis tower. I gave my position and by the time I got back to the plane, the highway patrol was there. Visual inspection showed the tanks to be empty. The state patrol pilot brought out 5 gallons of fuel and I flew into bis airport. The amount of fuel indicated the problem was a fuel outtage. The plane had had an annual 30 days earlier and an engine head was replaced. My calculations of fuel consumption should have put me into bis with 30 minutes excess. Back calculating the fuel consumption indicates approximately 14 gals per hour. My experience is approximately 9.5 gals per hour. In looking over engine performance data, flight planning should probably be done at about 14 gal per hour. Number of takeoffs, amount of taxi time, leaning procedures, gross weight, climb time, etc could have accounted for the difference. However, after refueling in bis, I refueled after 2 hours. I had carefully run the first tank exactly 1 hour with the climb out and found the fuel consumption at 15 gals per hour. Therefore, I am having my a&P look over the engine for any potential leak situation. The plane was close to gross weight, but the center of gravity was well within limits and it trimmed very good. In approximately 300 hours of flying this plane, I have never burned 15 gals in 1 hour. In fact the highest overall consumption I have ever had was about 11.5 gals per hour. No accident occurred, no injury resulted. Callback conversation with reporter revealed the following: reporter stated that aircraft flew from denver to pierre, sd where refueling was done. Tanks indicated full, visually and by gauges. Flight proceeded on to cook, mn and then on to bismarck, nd total round trip after fueling (no fueling at cook) was about 4:45 to 5:00 hours, leaving, as stated in text, about :30 minutes fuel in reserve. Reporter further cited fuel gauges as not being very accurate nor very reliable so not much reliance is made on the indications themselves, but more on a visual inspection of the fuel prior to flight. Further, it is very difficult, because of fuel tank design, to ascertain with any degree of reliability, the amount of fuel in tank unless it is indeed full. The gauges were only indicating 30-40 pounds of fuel in them when about 1 hour away from destination, bis, nd that would only be about :35 minutes of fuel under normal fuel consumption of 11 gals per hour. Reporter stated that the fuel gauges were always slow to react to fuel use and it didn't concern him as that was 'normal' (fargo and jamestown were on a straight line flight path about 1/2 and 2/3 of the way). The aircraft is a fuel injected reciprocating engine and reporter gave information on the mechanical condition of the servo fuel system. The diaphragm was ruptured and fuel was porting to both the fuel side as well as the air side. He had only 700 hours on a rebuilt unit. He noticed that on his cruise-leaning procedure that the egt cylinder temperature that is monitored during leaning was either sluggish or non responsive. His post thoughts give an insight of a problem with an ability to lean the engine to acquire a fuel use of 11 gals per hour as anticipated. Later fuel figures showed a use of 15 gals per hour. There were 2 items of concern that were passed on. One was the ruptured diaphragm and the inability to lean out. The second was that with this situation, the engine can also flood out when retarding the throttle, like on downwind or base leg and, on occasion, it has. This aircraft has a ram air door in front of the cowling. It should be opened (on the ground, with engine off) set mixture full lean, throttle open, auxiliary fuel pump north and look at or smell the impact tubes on the fuel servo. Mist or odor spells a problem!

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Original NASA ASRS Text

Title: EMERGENCY OFF ARPT LNDG. FUEL EXHAUSTION.

Narrative: I HAD JUST LISTENED TO ATIS AND CALLED BIS APCH. THE ENGINE BEGAN TO RUN ROUGH. FUEL PRESSURE WAS NOT STEADY. I ADVISED BIS APCH I WAS GOING TO LAND AND THAT I WOULD CALL THEM WHEN DOWN. I IMMEDIATELY SELECTED AN ISOLATED ROAD AND LANDED WITH SOME POWER. I DID NOT DECLARE AN EMER. AFTER LNDG AND INSPECTING THE TANKS VISUALLY, I WENT TO A TELEPHONE AND CALLED THE BIS TWR. I GAVE MY POSITION AND BY THE TIME I GOT BACK TO THE PLANE, THE HWY PATROL WAS THERE. VISUAL INSPECTION SHOWED THE TANKS TO BE EMPTY. THE STATE PATROL PLT BROUGHT OUT 5 GALLONS OF FUEL AND I FLEW INTO BIS ARPT. THE AMOUNT OF FUEL INDICATED THE PROBLEM WAS A FUEL OUTTAGE. THE PLANE HAD HAD AN ANNUAL 30 DAYS EARLIER AND AN ENGINE HEAD WAS REPLACED. MY CALCULATIONS OF FUEL CONSUMPTION SHOULD HAVE PUT ME INTO BIS WITH 30 MINUTES EXCESS. BACK CALCULATING THE FUEL CONSUMPTION INDICATES APPROX 14 GALS PER HOUR. MY EXPERIENCE IS APPROX 9.5 GALS PER HOUR. IN LOOKING OVER ENGINE PERFORMANCE DATA, FLT PLANNING SHOULD PROBABLY BE DONE AT ABOUT 14 GAL PER HOUR. NUMBER OF TKOFS, AMOUNT OF TAXI TIME, LEANING PROCS, GROSS WEIGHT, CLIMB TIME, ETC COULD HAVE ACCOUNTED FOR THE DIFFERENCE. HOWEVER, AFTER REFUELING IN BIS, I REFUELED AFTER 2 HRS. I HAD CAREFULLY RUN THE FIRST TANK EXACTLY 1 HR WITH THE CLIMB OUT AND FOUND THE FUEL CONSUMPTION AT 15 GALS PER HOUR. THEREFORE, I AM HAVING MY A&P LOOK OVER THE ENGINE FOR ANY POTENTIAL LEAK SITUATION. THE PLANE WAS CLOSE TO GROSS WEIGHT, BUT THE CENTER OF GRAVITY WAS WELL WITHIN LIMITS AND IT TRIMMED VERY GOOD. IN APPROX 300 HOURS OF FLYING THIS PLANE, I HAVE NEVER BURNED 15 GALS IN 1 HR. IN FACT THE HIGHEST OVERALL CONSUMPTION I HAVE EVER HAD WAS ABOUT 11.5 GALS PER HOUR. NO ACCIDENT OCCURRED, NO INJURY RESULTED. CALLBACK CONVERSATION WITH REPORTER REVEALED THE FOLLOWING: REPORTER STATED THAT ACFT FLEW FROM DENVER TO PIERRE, SD WHERE REFUELING WAS DONE. TANKS INDICATED FULL, VISUALLY AND BY GAUGES. FLT PROCEEDED ON TO COOK, MN AND THEN ON TO BISMARCK, ND TOTAL ROUND TRIP AFTER FUELING (NO FUELING AT COOK) WAS ABOUT 4:45 TO 5:00 HRS, LEAVING, AS STATED IN TEXT, ABOUT :30 MINUTES FUEL IN RESERVE. REPORTER FURTHER CITED FUEL GAUGES AS NOT BEING VERY ACCURATE NOR VERY RELIABLE SO NOT MUCH RELIANCE IS MADE ON THE INDICATIONS THEMSELVES, BUT MORE ON A VISUAL INSPECTION OF THE FUEL PRIOR TO FLT. FURTHER, IT IS VERY DIFFICULT, BECAUSE OF FUEL TANK DESIGN, TO ASCERTAIN WITH ANY DEGREE OF RELIABILITY, THE AMOUNT OF FUEL IN TANK UNLESS IT IS INDEED FULL. THE GAUGES WERE ONLY INDICATING 30-40 LBS OF FUEL IN THEM WHEN ABOUT 1 HR AWAY FROM DEST, BIS, ND THAT WOULD ONLY BE ABOUT :35 MINUTES OF FUEL UNDER NORMAL FUEL CONSUMPTION OF 11 GALS PER HOUR. REPORTER STATED THAT THE FUEL GAUGES WERE ALWAYS SLOW TO REACT TO FUEL USE AND IT DIDN'T CONCERN HIM AS THAT WAS 'NORMAL' (FARGO AND JAMESTOWN WERE ON A STRAIGHT LINE FLT PATH ABOUT 1/2 AND 2/3 OF THE WAY). THE ACFT IS A FUEL INJECTED RECIPROCATING ENGINE AND REPORTER GAVE INFO ON THE MECHANICAL CONDITION OF THE SERVO FUEL SYSTEM. THE DIAPHRAGM WAS RUPTURED AND FUEL WAS PORTING TO BOTH THE FUEL SIDE AS WELL AS THE AIR SIDE. HE HAD ONLY 700 HRS ON A REBUILT UNIT. HE NOTICED THAT ON HIS CRUISE-LEANING PROC THAT THE EGT CYLINDER TEMP THAT IS MONITORED DURING LEANING WAS EITHER SLUGGISH OR NON RESPONSIVE. HIS POST THOUGHTS GIVE AN INSIGHT OF A PROBLEM WITH AN ABILITY TO LEAN THE ENGINE TO ACQUIRE A FUEL USE OF 11 GALS PER HOUR AS ANTICIPATED. LATER FUEL FIGURES SHOWED A USE OF 15 GALS PER HOUR. THERE WERE 2 ITEMS OF CONCERN THAT WERE PASSED ON. ONE WAS THE RUPTURED DIAPHRAGM AND THE INABILITY TO LEAN OUT. THE SECOND WAS THAT WITH THIS SITUATION, THE ENGINE CAN ALSO FLOOD OUT WHEN RETARDING THE THROTTLE, LIKE ON DOWNWIND OR BASE LEG AND, ON OCCASION, IT HAS. THIS ACFT HAS A RAM AIR DOOR IN FRONT OF THE COWLING. IT SHOULD BE OPENED (ON THE GND, WITH ENGINE OFF) SET MIXTURE FULL LEAN, THROTTLE OPEN, AUX FUEL PUMP N AND LOOK AT OR SMELL THE IMPACT TUBES ON THE FUEL SERVO. MIST OR ODOR SPELLS A PROBLEM!

Data retrieved from NASA's ASRS site as of August 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.