PPRuNe Forums - View Single Post - AF447 final crew conversation - Thread No. 1
Old 19th October 2011 | 23:22
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AlphaZuluRomeo
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From: FR
RetiredF4:
How do you translate "10° climb" in Nz demand? After all, once stalled, the g were around 1...
The law is not a "pure" g-demand one, IIRC. "Corrected for the path", or something like that. Cannot do the maths, but would be interested to know more.

deefer dog:
1/ No, unless switching off many computers (=not a feature/approved procedure). Against the Airbus philosophy.
2/ There is no such computer logic. Perhaps you've read Otelli litterally? Well, he's wrong here, there is no logic AoA>41°=Cancel SW.

The logic is :
- if current AoA > value calculated for SW then
-- SW is triggered

- if speed < 60kts then
-- AoA measurement is deemed not valid, whatever value the probe sends is "cancelled" (& AoA is flaged "NCD", no computed data); reason for doing that is [my guess] that will less than 60kt of relative wind, there is not enough airflow to get a correct/precise AoA measure from the AoA probes

The "problem" is that if AoA is "NCD", then AoA value (or "non-value") does not validate the condition for the stall warning: "NCD" is not superior to X degrees AoA.
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