A319
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Aircraft Equipment Problem Critical; Deviation - Speed All Types; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Overcame Equipment Problem; General Maintenance Action
Aircraft; Company Policy; Procedure; Software and Automation
FL360 ISA -54C; REC MAX ALT (recommended maximum altitude) 39.8. MCDU weight 132.8. Green dot speed 229 KIAS. Vls 220 [lowest selectable speed for autopilot]. Takeoff Data Performance derived green dot corrected one knot per 1;000 feet above FL200 equals an under FL200 green dot speed of 213. A 213 KIAS green dot from 3.5.4 of the Performance Manual is the speed for a 141 knot jet (8;200 pound difference). FAC1 (flight augmentation computer) and FAC2 averaged to 140 kts. Flaps full landing. Vls 128 KIAS. MCDU Vapp was 123 (5 knots into the hook). Out of an abundance of caution; we added 10 knots to get to Vls+5. Landed uneventfully and under max landing weight even if you added in the 8-9 kts (worst case scenario). Documented all in the aircraft logbook. For the committee; this is the second 319 that has presented a large difference in MCDU weight vs. calculated weight from FAC1/FAC2 (which generates Vapp and Vls on a basic jet). Either the jets EOW (empty operating weight) is wrong; the software is corrupted or the alpha vanes are out of calibration. I think safety and maintenance need to do a deep dive in to the FAC's and alpha vanes and any software changes of late. The only other explanation is an error in the EOW which is hard to envision. I would like a response directly from the committee about this and [another] aircraft which was previously accepted in to report system. I am concerned that given the increase in the number of pilots who are not flying regularly due to schedule reductions; this could result in an incident or mishap.
Flight Crew reported speed progamming issues and elected to manually fly computed higher speeds due to suspected equipment issues.