What was found
CTR TANK FUEL QUANTITY FLUCTUATES IN FLIGHT FROM 60 LBS TO 1080 LBS. SHOWED 1.0 IN CTR FOR TAKEOFF. STAB TRIM WAS ADJUSTED ACCORDINGLY. NOSE WAS VERY LIGHT ON TAKEOFF ROLL AND TOOK EXCESSIVE NOSE DOWN TRIMMING TO GET AIRCRAFT IN TRIM. ONCE IN FLIGHT RECHECKED T/O SETTING AND THEY ARE CORRECT. VERIFIED FUEL QTY IN CENTER TANK. NO FLUCTUATION AND FUEL QUANTITY READS NORMAL. FOUND WATER TRAPPED IN THS COMPARTMENT MEASURED 14 INCHES DEEP, AFT PRESSURE BULKHEAD. APPROX 60 GALLONS. BLEW OPEN DRAIN AT MAST AND DRAINED ALL WATER FROM COMPARTMENT. ENSURED DRAIN IS OPEN AND COMPARTMENT IS EMPTY OF WATER AMM 51-80-41-6.