PA30 PLT HAS FUEL STARVATION AND LANDS AT AUS.

Narrative

FLT WAS FROM HDC TO ZZZ. WHILE TRANSITIONING AUSTIN CLASS C AIRSPACE; THE R ENG LOST PWR. AFTER CHKING FUEL SELECTOR WAS ON MAIN TANK AND AUX FUEL PUMP SWITCHED ON; ENG WAS EVENTUALLY SHUT DOWN AND PROP FEATHERED. A CALL TO APCH WAS INITIATED DECLARING AN URGENT NEED TO DIVERT TO AUSTIN FOR A PRECAUTIONARY LNDG. THE LNDG WAS COMPLETED WITHOUT FURTHER INCIDENT. UPON EXAMINATION OF ENG; IT WAS DETERMINED THAT FUEL STARVATION WAS THE CAUSE OF THE LOSS OF PWR. FUEL WAS ADDED AND ENG WAS GND RUN AND CHKED OK. FUEL REQUIREMENT FOR THIS LEG WAS OBTAINED DURING PREFLT PLANNING. HOWEVER; MY CALCULATIONS OF FUEL ON BOARD PRIOR TO DEP WERE MISCALCULATED. MY ORIGINAL FUEL CALCULATIONS WERE BEING CONFIRMED DURING THE FLT BY REF TO MAIN TANK FUEL QUANTITY INDICATORS. IT IS NOW OBVIOUS THAT THE INDICATORS HAVE A SIGNIFICANT ERROR IN THE READINGS. UPON DEP FROM HDC; I CARRIED 30 GALLONS IN THE AUX TANKS AND CALCULATED 25 GALLONS IN THE MAIN TANKS; FOR FLT ENDURANCE OF 3.6 HRS AT A FUEL BURN OF 15.2 GPH. MY PREFLT PLANNING WAS FOR 3 HR FLT TO ZZZ. MAINS ARE 60 GALLON CAPACITY WITH 54 GALLONS USABLE. THE CAUSES OF THIS FUEL MISMGMNT INCIDENT ARE SEVERAL IN THIS CHAIN OF EVENTS AND ARE AS FOLLOWS: 1) I HAD VARYING AMOUNTS OF FUEL BURNED OUT OF THE MAIN TANKS FROM 3 PREVIOUS FLT LEGS. THIS CAUSED MY FUEL CALCULATIONS TO HAVE A SIGNIFICANTLY HIGHER DEG OF ERROR OF ACTUAL FUEL BURNED WHEN I CALCULATED MY FUEL ON BOARD FOR THE FLT LEG IN QUESTION. NEEDLESS TO SAY; I DID NOT KEEP AN ACTUAL WRITTEN FUEL LOG AND I COULD ONLY ESTIMATE FUEL BURNED PRIOR TO DEPARTING HDC. 2) I HAD SIGNIFICANTLY INACCURATE FUEL QUANTITY INDICATORS THAT ONLY REAFFIRMED MY NOW MISCALCULATED FUEL ON BOARD. 3) I HAD A MARGINAL FUEL ON BOARD VERSUS FUEL REQUIREMENT SIT WITH NO ADDED SAFETY MARGIN. IN THE FUTURE; I WILL PAY MORE ATTN AND CONDUCT A MORE THOROUGH PREFLT PLAN. I WILL ADD A GREATER SAFETY MARGIN TO MY FUEL REQUIREMENTS. I WILL KEEP A MORE ACCURATE AND WRITTEN LOG OF FUEL BURNED FOR EACH FLT LEG. I WILL NOT ATTEMPT TO CALCULATE OR ESTIMATE FUEL BURNED FROM SEVERAL PREVIOUS FLT LEGS. I WILL PAY MORE ATTN TO RECOGNIZE A MARGINAL SIT AND ACT IN A SAFE AND PRUDENT MANNER SO AS TO COMPLETE THE FLT SAFELY.