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Old 26th Oct 2013, 10:09
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Owain Glyndwr
 
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rudderrudderrat

I agree. Unfortunately no one has yet designed a system which never fails.
And never will, but in this case (take-off) we were addressing a situation where there were no system failures, just vanes moving as a result of atmospheric turbulence I think.

Therefore the 60 kts IAS logic inhibited the valid AoA probe information.
The stall warning should be independent of IAS when airborne.
Strictly speaking the stall warning cannot be independent of IAS because one needs some sort of speed signal to cater for warning threshold variations with Mach Number.

I agree that the logic inhibited valid AoA data, but as I said earlier keeping the stall warning sounding irrespective of measured IAS until there is a valid return to AoA below the threshold would fix that. I assume here that excursions in measured AoA outside the S/W threshold below 60 kts and on the ground would be transients so that the conditions for switching off the warning would be quickly satisfied.
Perhaps I should also say that so far as I can see, it would not be necessary to change the existing AoA validity logic to make this work. All that is required is that the stall warning logic be changed to remove the warning only when a VALID AoA signal shows that safe conditions are restored.

Last edited by Owain Glyndwr; 26th Oct 2013 at 11:12.
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