What was found
UPON REACHING CRUISE ALITIUDE OF FL 400, BOTH THE LT & RT MAIN FUEL TANK QUANT INDICATORS WENT BLANK AND RECEIVED "FUEL QUAN IND" STATUS MSG. AFTER REACHING 4000' BOTH INDICATION CAME BACK ON WHILE FLYING APPROACH. PERFORMED THE WALK THROUGH FIM 28-41-00 TREE 857 AND NO DEFECT NOTED. PERFORMED A FUEL QUANTITY BITE PROCEDURE IAW AMM 28-41-00-5-2. NO HISTORY NOTED, AND NO CURRENT FAULTS NOTED. INSTALLED FUEL QUANTITY PROCESSOR IAW AMM 28-41-08-4, PERFORMED OPERATIONAL TEST- FUEL QUANTITY INDICATING SYSTEM IAW AMM 28-41-00-5-2. OPS TESTED GOOD, NO DEFECT NOTED. THE FUEL QUANTITY PROCESSOR RACK, PINS AND PLUG HAS BEEN INSPECTED FOR ANY DAMAGE AND SECURITY, NO DAMAGE NOTED. ACFT OK FOR SERVICE.