What was found
AT PUSHBACK, FUEL TANKS READ LEFT 8.5, RIGHT 8.6, CENTER 25.9. DURING CRUISE, MAIN TANKS SLOWLY DECREASED TO LEFT 7.93, RIGHT 8.17 BY THE TIME THE CENTER TANK REACHED ZERO. OUTSIDE TEMP -64C. FUEL TEMP GOT TO -30C. ACFT GROUNDED. ACCOMPLISHED TASK CARDS NG-28 FCD -18090-1 & NG-28FCD-18088-1. FOUND THE NR 1 TANK HAD SEVEN BAD PROBES & NR 2 TANK HAD SIX BAD PROBES. PROBES REMOVED & REPLACED.