MD-11
Flight Crew Air Transport Pilot (ATP); Flight Crew Flight Engineer; Flight Crew Flight Instructor; Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Last 90 Days 200; Flight Crew Total 17000; Flight Crew Type 5000
Confusion; Human-Machine Interface; Troubleshooting
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy
General Maintenance Action
Aircraft
I received the weight and balance and entered it into the FMS. Our weight was 630;000 LBS. Maximum Structural Takeoff Weight was 630;500 LBS. We did our CG verification procedure and the aircraft; FMS; and paper Weight and Balance all agreed that our takeoff weight was 630;000. After breaking ground I noticed the gross weight of the aircraft had increased to 632.0 and continued to increase and stabilized at 633;700. During the flight I continued to monitor the weight and all the FMS calculations as well as my personal fuel burn log agreed with the takeoff weight of the newly computed gross weight of 633.7. Just prior to taking the runway I did verify the TOGW of 630;000 which also reflected the taxi out burn of 1;500 LBS. I have submitted reports before on this aircraft for faulty weights as well as its sister ships; all of which came from another air carrier. Previous reports concluded the problem with these aircraft were the fuel probes in the #2 tank; which are made by Parker Industries. The miscalculation of the fuel quantities has led to many overweight takeoff events and continues to be an issue. Upon arrival at our destination I did write this overweight takeoff indication in the logbook and observed while Maintenance checked for faults. No system faults were noted but an overweight takeoff was recorded by the FMS.
Immediately following a Maximum Allowable Structural Gross Weight takeoff an MD-11 Captain noted a 3;700 LB increase in the FMS generated aircraft gross weight. His previous experience leads him to believe this type of error is chronic on all the aircraft in his company's fleet that were purchased from another carrier and is associated with faulty fuel gauges in the #2 fuel tank.