OK465, the "flight director" of the bird is called FPD, not FD. Of course it has it's own "flight director" but please don't confuse people with wrong names. FD is generated by FMG(E)S, FPD by IRS.
Dani, the flight director for the FPV is indeed correctly termed the
Flight Path Director (FPD) as opposed to FD, as you say.
My bad. I certainly don't want to confuse anyone.
However, the steering cue called the FPD is selected by the
FD button, and provides the equivalent single cue steering commands for the FPV that the dual cue pitch and bank steering bars provide for the aircraft attitude symbol in all FMA annunciated lateral and vertical modes other than selected TRK & FPA.
It provides, for the FPV, managed nav steering, climb/descent/alt hold steering, approach steering, both ILS & RNAV, all from the same FMGEC inputs that are used by the
other 'FD' steering bars. FPD is only purely inertially referenced when TRK & FPA are annunciated in the FMA, precisely because these are inertial parameters.
In addition, with failure of any inputs required to display proper FPD steering, an
'FD' flag will be displayed, same as if the dual cue FD had been in use.
It's a 'flight director' in the same sense that a HUD steering command symbol is, no different.
(As a side note, I still think the jury is out on the pitch moment issue regardless of how 'tiresome' it may be. Lot of assumptions being made...)