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Old 2nd Jun 2010, 08:21
  #225 (permalink)  
robdean
 
Join Date: Aug 2005
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I'd analyse the above graphic (#218) this way:
(throughout bearing in mind reaction time / inertial delays)

Prior to A:
Establishing good glidepath but then offsetting low due to tracking radalt.

From A->B:
Rate of Descent stabilised again: similar to intended glidepath, simply offset low. However radalt tracking falling ground so implies approx zero RoD, 100m alt.

B->C
Response time to second '100m' call.

From C to CFIT:
i) Mistaken attempt to remedy apparent zero RoD. Thus trending to new descent rate: 'the ground incline at around 20s' plus 'intended RoD' (leading to maximum RoD: at about 13 seconds)

ii) Excessive RoD becomes immediately apparent despite 'trust-the-radalt' mindset as terrain is now rising, but combination of:

Glideslope RoD
plus
RoD compensating for previous terrain downslope
plus
effective RoD from terrain upslope

adds up to:
Game Over.
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