Disagreeing Flight Directors - A320

[Bula]

G'day All,

Just wonding if anybody would be able to shed some light.

On departure, GPS primary. No FM/GPS disagree. FMGC syncronised, Captain FD indicates a turn to intercept, FO FD is still squared for a few moments then begins to indicate the turn.

I have seen this usually during climb. One FD may indicated a different target attitude than the other.

Can anyone shed some light on what might cause this?

[mcdhu]

Disagreeing FD Bars in the A320 series - seen mainly in descent - is the result of slightly different calculations between FMGC 1 and 2. The autopilot will of course satisfy the FD demands allied to the engaged autopilot and thus the PNF will see the FD discrepancy.

Hope this helps,
mcdhu

[Bula]

Thanks for that. I've never seen it when calculating a lateral flight path though. Thought it was a bit strange.