not quite ft, one will cross the the threshold at the promulgated TCH, whichever that might be. in case of HNL 08L it's 80 ft. The question here is when should LDA beyond GS be used if at all? As we've learned there's a discrepancy between the certification data based on 50 ft TCH and promulgated TCH which in turn will be adjusted to coincide with the GS and VASI, aiming point. Bottom line is instead of touching down at 850 ft with 480 ft/min as assumed in AFM you'll fly the ILS till the CAT I minima then transition to visual aiming for the aiming point thus touching down at closer to the 1300 ft mark. That's about the figure corresponding to the LDA beyond GS. Therefore when your operational landing distance is smaller than beyond GS you're good to go. In the extreme case you could be within the threshold value but above GS one. I think all those publications have made it clear that certification isn't real life neither on the performance side nor on the installation one. Be wary of the odds might prove useful.
