A300-600
Flight director disagree.
I have never seen this before on an airbus!
AP2 engaged.Modes are v/s and loc with gs armed. Aircraft is cleared to 2000ft and further with the glide.
F/o PFd GS* as glideslope captures at approx 2300ft.Ap1 engaged as plan is practice autoland.
Capt Pfd Alt* as approaching fcu altitude as GS* not annunciated.
AP1 now master autopilot so aircraft attempts to acquire fcu alt and not the glideslope.
Glideslope is now showing fly down so both autopilots and fd disengaged and a manual approach and landing flown.
Does anybody have any ideas as to why this happened?
Double rad alt fail will cause neither fd to arm in gs on the minibus but never seen it as a failure just on one side!