PPRuNe Forums - View Single Post - Airbus Within 6ft of the Ground nearly 1 mile Short of Runway
Old 15th Jul 2022, 08:06
  #126 (permalink)  
Uplinker
 
Join Date: Nov 1999
Location: UK
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@A320LGW;
The plates we use at least don't include any height v distance table

Yes exactly; that's why I am suggesting it. With a NPA approach, you are heavily reliant on having set the correct QNH, and have no means of cross checking that you are on the correct profile - as you do with a ground transmitted glide-slope. Bear in mind it may be IMC, with absolutely no external visual references and a bad radio link in a noisy cockpit, with language issues. A surveyed series of Rad Alt heights, for, say, the last 4 miles* written on the NPA plate might be an easy way of providing that cross check, and allowing a safe go-around if something did not match up. Checking altitudes against distance to go on a NPA is useless if the QNH is set wrong, as this near CFIT has shown.

Even if a crew does monitor the Rad Alt, the terrain might not be flat, as you say, so the readings might be quite different from the altitudes - even if using QFE, so not always easy to decide if the Rad Alt figure is reasonable or not. Having a series of surveyed heights vs distances on the plate, might give improved reassurance?

*Or perhaps just one radio altimeter check height printed on the plate for the 4 nm point would serve as a gross error check?
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