Our 744s have twin GPS and NGFMC so we can fly RNAV final approaches down to RNP1 specification. In fact the RNP1 minima are sometimes below the minimum autopilot disconnect height for a NPA so that becomes the lowest MDA.
When flying an RNAV transition or final approach the autopilot MUST be used in both LNAV & VNAV to guarantee the required vertical and horizontal accuracy. The database approach in the FMC MUST be used and cannot be modified in any way by the pilot. You certainly CANNOT build your own approaches. In my docs there are no RNAV approaches at all published at FRU.
With the RVR conditions on the day at around 350M both a Cat II ILS and an automatic landing were mandatory. It is NOT permitted to carry out manual landings with RVR below Cat I conditions (550M for FRU26). The B744 has 3 ILS recievers - It only needs 2 of them to execute an autoland.
Personally I have had a couple of autolands in my career in RVR below 200M where I had to intervene to avert a mishap, but that situation is very rare as automatic landings with rollout are VERY reliable. Consequently Captains tend to be comfortably in the mindset of 'we are landing off this approach'. Where the approach has a visual decision point (like Cat II), that decision is slightly academic because... in the absence of outside influence the aircraft will reliably continue below minima down the ILS, land and safely roll-out with absolutely no pilot input.
It is clear from the traces that the aircraft was accurately established and maintaining the centreline, they were also descending at an accurate ROD consistent with automatic control.... although way above the glide path.
The map of the debris field above is not consistent with a stall from height. This aircraft flew into the ground at medium speed at a shallow angle consistent with the earlier ADS-B ROD figures. I suggest the final ADS-B points suggesting a GA are crash corruption.
I believe this aircraft had captured the localiser but never ever captured the glideslope. They continued to descend in V/s without noticing they were getting higher & higher above the glide. There would have been no 'Land 3' FMA annunciation at 1500', no FLARE or ROLLOUT armed and at 1000' instead of taking control the Captain should order a GA if 'Land 2 or 3' are not showing.
If I am correct and all this is later proven to be true, we are talking about mishandling of epic proportions.