Large Transport
Aircraft Equipment Problem Less Severe; Deviation - Speed All Types
General Maintenance Action
Aircraft
On approach to Airport ZZZ; winds calm; temp -01; altimeter 30.41; landing weight 302;800 pounds; the FMS generated speed with 35 flaps was 135 knots. The tab data speed from QRH was also 135 knots. At that speed; the AOA (Angle Of Attack) was outside of the approach range at 8.8 instead of a more appropriate value of 7.5. Actual pitch attitude was 6.0 degrees instead of a more appropriate value of 4.5 to 5.0 degrees. I commented to the First Officer (FO) that the aircraft felt mushy as if flying in slow flight. The FO said he could tell that just by watching the ineffectiveness of the controls. In order to get the proper pitch attitude we had to fly the aircraft 7 knots fast by manually entering 142 in the approach speed. Something is wrong with aircraft that causes the AOA and pitch to be high when flying the proper IAS. This tells me that there is possibly a problem with the pitot static system that is giving the wrong IAS or the BOW (Basic Operating Weight) listed for this aircraft is wrong. The sign off for this aircraft involved reloading the last FMS database. I am concerned that this is passing the same problem to another unsuspecting crew. If the FMS database had been to blame; then the FMS speeds would not have matched the tab data speeds. Also; if the FMS had a corrupted load; shouldn't maintenance have gotten an error report when it was first loaded? If an FMS loading device was somehow able to enter a corrupted load without giving an error; was that same loading device used on any other aircraft? Maintenance has already signed this off once with a solution that could not possibly solve the real problem. It seems as though this is happening again.Can we pull the FOQA (Flight Operations Quality Assurance) data for the flights after the FMS was reloaded to see if the AOA and pitch was still high when flying the proper speeds on approach? Otherwise; I would re-weigh the aircraft; check the pitot static system; and test fly this aircraft. We do not need another landing incident!
Large Transport Captain reported possible issue with the aircraft pitot/static system or the FMS data load that generates a speed too slow for configuration.