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Old 17th Apr 2017, 00:00
  #1099 (permalink)  
ukv1145
 
Join Date: May 2007
Location: Scotland
Posts: 53
Originally Posted by [email protected] View Post
GKaplan and ukv1145 - OK, I get the subtleties now with the modes and the LOW ALT selection - so we are saying that the mode 2 would have alerted if Blackrock had been in the database and the LOW ALT mode had not been selected?
No, not quite. All of the numbered modes are legacy modes, designed before the eventuality of the terrain database and the enhanced 'look forward mode', so it would not have made any difference to mode 2 if Blackrock was in the database. Mode 2 MAY have triggered a warning if it had not been inhibited (boundaries reduced) by the Low Alt switch but this would depend on the nature of the terrain overflown, it will not give sufficient warning to very steeply rising terrain such as a cliff (which I imagine to be the case with Blackrock) as it is still only using the rad alt to look down and the warning will be given based on the rate of change of that rad alt signal.

Last edited by ukv1145; 17th Apr 2017 at 00:14.
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