Things have happened and only lessons can be drawn from these events.
Basic common sense tells you; if you have no visual cue’s to land from at the latest at DA or MAP, you make a go around!
But visual cues are not the only thing that may fail.
A thorough knowledge of ILS systems reveals that although LOC and G/S may well be centered it does NOT mean the Aircraft is within the limits or centered with the runway center line.
Some Airlines allow the F/O to continue an autopilot coupled approach (on the condition the LOC and G/S are centered) even if the Capt does NOT react at DA or MAP assuming incapacitation.
The logic behind this is that it is far safer to continue on the Autopilot than to carry out a missed approach with the autopilot by the F/O only.
Edited:
The logic behind this is that it is far safer to continue on the Autopilot and land than to carry out a missed approach with the autopilot monitored by the F/O only.
Another issue is that of extra fuel, 15 minutes is nothing!
If you take extra fuel, then you take plenty and not what I call some kind of psychological fuel of 15 min but at least 30 min if not 60 min.
Not so long ago there was a 757 cargo in LIME with TS all around the place and the same scenario nearly developed.
Again the crew took ONLY 15 min extra, all this causes a tremendous amount of stress and leads to errors.
Considering the small amount of extra burn due to the uplift there is no valid reason why this extra burn should not be considered as an insurance premium against tragedy.
It can only be explained as either reckless behaviour and/or bad company policy.
It is not a question of training but of common sense, only!
There are no clear criteria set out but if you check the WX and you see TS at your destination the you go and look how widely spread they are.
If it is confirmed that they are all over the place and not in a confined area only, then you know what your chances are.
Far too often, do we think that aviation is state of the art technology, perfectly regulated and controlled all this creates a blind confidence in the system.
Everybody with some years in the industry knows for a fact that it is far from perfect