PPRuNe Forums - View Single Post - A320 Positive Static Spiral Stability in Turbulence
Old 17th Dec 2011, 16:23
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Field In Sight
 
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TP. Thanks for that. It's exactly as I thought.
BOAC. Wording is from Airbus docs, but I do mean lateral/roll stability.

It's just typically vague airbus information regarding this subject. I've found the following statements in various google searches:

"Even in turbulent conditions, the control law resists the
disturbances well without pilot inputs." http://www.smartcockpit.com/data/pdf...ing_Manual.pdf

"Resists" is pretty vague, in my view this means that it immediately counters any uncommanded rolling moment, whilst the rolling moment is present. i.e. "neutral static spiral stability".

But I found this other reference:
Babylon 9 Translation Software and Dictionary Tool

ON A320:
.neutral spiral stability as commanded by the pilot but positive spiral stability in case of external disturbance.
.positive spiral stability beyond 33° bank angle.
.in case of engine failure contenaining the bank angle into a safe limit

I take it that the "in case of external disturbance" statement means that the "positive static spiral stability" occurs only because the disturbance has rolled the aircraft past 33 degrees.

Last edited by Field In Sight; 17th Dec 2011 at 16:39.
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