Rudder trim reset A320

[Speedwinner]

Quick one folks: why do we reset the ruddertrim after engine start on the 320? What's the technical reason for that? Can't we do it without engines running on the gate position or ramp position?

Thanks!

[vilas]

Elementary Watson! For the same reason you can't set the stab for take off without engines running.

[Denti]

I still wonder why the bus doesn't set the trim itself, after all the CG is set in the INIT page. And it usually trims itself as well, why not just set the trim as well?

[FlightDetent]

The later 330s do.