Originally Posted by fiddlair
Here's another gum for you to chew: On an ILS if you follow 1 dot above the glide all the way down to runway, where you gonna touch the runway?
According to the FCOM's, it says "at 50', one dot low means you will be 14 feet low" so based on their logic, one dot high would mean 14 feet high which would mean eating up a LOT of landing surface.
...But if you follow the one-dot-high beam exACTly down to touchdown, you would be touching down EXACTLY at the normal touchdown point (plus the distance the G/S needle is displaced on the ILS display on board) past the "normal" touchdown point. (Stick with me now, folks) In other words, like, 0.25 cm's. (You would have to keep adjusting that "one dot high" with some fast finesse all the way to touchdown in the same way you would "home" to a beacon vs "track with wind-correction". Kapish? No? Get a beer and re-read it then, hombre.
HowEVER, if you kept yourself above the dot to a "cut-off" point somewhere along the approach-path, after which you would transition to the VASI's (etc), and kept yourself, say, 2 1/2 white for eg, then you will touch down long (as is a sadly over-practiced habit where the crew have only flown into vast tracts of endless runways all of their career).
I've seen crew proudly boast they did a great landing... (yes, habibi, but it was 2,000 feet beyond the touch-down zone).
I'll guess, with a FIRM landing, say...6 to 800 feet.
Cheers,
R.D.