Landing distance available
This is probably a geeky question but I've yet to get a concise definition regarding LDAs as stated in the Jeppesen manuals. None the wiser even after consulting the grey info books.
Here's an example:LHR 27L and 27R shown as full length ie no displaced threshold. However, 27R gives 2 values whereas 27L only "beyond g/s". I don't have the chart in front of me but I jotted down the numbers.
27R distance available: 12,743 ft
27R glideslope : 11,586 ft
27L only gives a g/s value of 10,905 ft although runway geometry appears the same ie no displaced threshold.
My two questions are: why the difference here at LHR and when, in general, would you use the glideslope figure/