Throughout most of my flights I do everything correctly, eg, QNH etc set right.
But when i takeoff and begin my departure i turn on AP and set it to FL65 (for example) but then i am at 4000 and the controller says im at 11000ft (from his screen)! I don't get this, what is going on!!!!
I fly a addon A320 with default A321 panel
I became suspicious and when i went offline VATSIM and flew in a 733 to see if it was just the A320. The 733 did the exact same thing and the PFD was very slowly going up. When i looked outside of the window when my PFD said 6000 it looked like (looking outside