I flew 777 as well, so please advise me when I can't make the gradient taking into account the above.
1) When below minima, the point of this whole thread.
2) When reducing landing weight involves jettisining all ones fuel plus more- not always optimal!!!
In cases where the GA performance is questionable, eg gear no retraction, the approach should not be commenced unless a landing is assured.
No landing is EVER 100% assured!!