Why does the A-320 allow 1.3 degrees more left rudder trim than right? On the a320, can someone explain why this is:


  AMM 27-22-00 PB 001
  NOTE:The maximum admissible rudder trim limits
  indicated on the control panel when the aircraft is stabilized in
  heading with the AP engaged are RH 1 DEG and LH 2.3 DEG.


Why is there a 1.3 difference in deg between LH &amp; RH?
Both engines turn the same way, and the bypass fans exert torque in order to accelerate the air passing through them. The torque needs to be trimmed out using aileron &amp; rudder trim.