What was found
PILOT REPORT ACFT WILL TAKE AN ATTITUDE OF 3 DEGREES NOSE UP AT ALL PHASES OF FLIGHT ANY TIME. THE AUTO PILOT IS DISCONECTED. OPEN T.H.S ACCESS PANEL AND NOTICED ACCUMULATION OF WATER ABOUT 14 INCHES HIGH RIGHT BEHIND PRESSURE BULKHEAD. UNPLUGED DRAIN IN ORDER TO CLEAR WATER OF THE COMPARTMENT. APPROXIMATELY 75 GALLONS OF WATER WERE DRAINED. TAKING INTO ACCOUNT A GALLON OF WATER WEIGHTS 8.3 LBS IT WOULD BE APPROX 622LBS OF WEIGHT PLUS ARM LEVERAGE THAT IS THE MOST PROBABLE CAUSE FOR THE NOSE UP ATTITUDE OF THE AIRPLANE.