A CESSNA T206 IN CRUISE AT 3500 FT DIVERTED DUE TO CRITICAL FUEL SIT.

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FLT PLAN CALLED FOR CONSUMPTION OF 100-105 GALLONS MAX FOR ROUND-TRIP FROM ZZZ TO HSE TO ZZZ. FLT PLANNING WAS DONE WITH DUATS USING REAL TIME CURRENT WX PLUS WINDS PRIOR TO FLT AND POH FOR CESSNA T-206 PERFORMANCE FUEL BURN SECTIONS. ACFT JUST OUT OF MAINT JUST HAVING 'FLYNT' WING-TIP TANKS INSTALLED -- FIRST FLT OUT. NOTHING EXTRAORDINARY ABOUT FLT TO HSE OR RETURN LEG UNTIL N OF ACY. XFERRED TO FLT FOLLOWING FROM ACY TO WRI. NOTICED FUEL GAUGES AT WRI WERE INDICATING MUCH LESS FUEL AVAILABLE THAN PREFLT PLANNING OR DURATION OF TRIP -- 4.3 HRS SHOULD HAVE SHOWN. LOW FUEL ANNUNCIATOR LIGHT FOR L TANK WENT ON AND I INDICATED TO WRI I WOULD BE DIVERTING TO TTN FOR FUEL WHICH WAS APPROVED. TOTAL FUEL ON BOARD AT START OF FLT WAS 88 GALLONS USABLE IN MAINS AND 29 GALLONS USABLE IN FLYNT TIP TANKS. FUEL XFER TIMED AND NOTED ON ZZZ TO HSE LEG OF TRIP. AT THE POINT OF DIVERTING TO TTN; I SHOULD HAVE HAD 25-30 GALLONS OF USABLE FUEL IN THE MAIN TANKS. UPON MAKING MY STANDARD RATE TURN TO TTN; BOTH L AND R FUEL ANNUNCIATOR LIGHTS ACTIVATED; STAYED ON; AND FUEL GAUGES FOR L AND R MAINS WERE INDICATING NEAR ZERO. NOT KNOWING IF I HAD A FUEL LEAK DEVELOPING (PLANE FIRST TIME OUT OF MAINT AFTER TIP TANKS AND NEW PLUMBING INSTALLED) OR GAUGES WHICH WERE INACCURATE; I NOTIFIED WRI FLT FOLLOWING I HAD A 'CRITICAL' FUEL SIT AND REQUESTED VECTORS TO NEAREST ARPT. WRI WAS NOT ABLE TO COMPLY WITH VECTORS. I THEN REQUESTED PERMISSION TO LAND AT WRI AFB DUE TO CRITICAL FUEL SIT. PERMISSION WAS GRANTED TO LAND ON RWY 36 AT WRI AFB. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE AIRPLANE WAS RETURNED TO MAINT TO CHK FUEL; QUANTITY INDICATION; ACTUAL USABLE FUEL STORAGE AND THE FUEL XFER SYS FROM THE TIP TANKS. THE RPTR SAID ALL SYS CHKED OK AND THE AIRPLANE HAS FLOWN WITH NO PROBS.