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Airbus Protection against rudder deflection under Normal Law...

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Airbus Protection against rudder deflection under Normal Law...

Old 13th Mar 2018, 10:21
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Airbus Protection against rudder deflection under Normal Law...

Given the well known pitch and bank protections under Normal Law, I was taken to believe that should an inadvertent full deflection of the rudder using the rudder pedals be done the systems would still prevent over banking and pitching, but I've been told that it's not really the case ( ? )

Imagine a scenario where, just after takeoff, already airborne and climbing towards acceleration height, full left or right rudder is input. What will happen regarding the yaw-induced roll ? What about the resulting pitch moments ? Would it be possible to "roll inverted" under such circumstances, or:

.) the forces required for any effective roll due to yaw are so huge that it would not be possible;

.) the protection logic also covers this sort of scenario.

Thank you for any hints
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Old 13th Mar 2018, 11:48
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Interesting one,

Yes, concerning the rudder, there is no protection (either in Norm, Alt, Dir laws)
But for sure, if you use full rudder deflection you may/will exceed VA.

For the rest of your question ????

Last edited by Feather44; 13th Mar 2018 at 11:58.
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Old 13th Mar 2018, 12:22
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Isn't that what the RTLU (Rudder Travel Limiter) is for?

When it fails things can go bad very quickly.

AirAsia Flight 8501 Crash Caused by Pilot Error, Rudder Units - Avionics
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Old 13th Mar 2018, 15:37
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FCTM gives nice info about how to handle the rudder.

FCTM/AC Systems/Rudder
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Old 13th Mar 2018, 22:11
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Thank you all guys for your answers / hints.

A situation in which inadvertent rudder deflection would be used, and the rudder limiter couldn't prevent is certainly extreme.
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Old 14th Mar 2018, 17:39
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I once had a student do the following: Slowed down to up speed ,pulled the nose gently up, promptly rolled towards 60 plus deg,THEN applied full rudder!
YeeeeeHaaaa, did she ever roll!!
On our back before I could say DONT!

After a quick sim reset we ended the A320 intro and moved over into the Dornier 328 Jet Sim were we actually were supposed to be!

Conclusion: You could possibly roll or at least invert an Airbus, but why would You!?

PS
The Dornier 328 was rolled in the alps on a empty sector.
Was not me!!
DS
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Old 16th Mar 2018, 03:54
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I haven't tried it but I reckon the protections would manage to prevent it from fully rolling

BluSdUp, why? For kicks!!!
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Old 16th Mar 2018, 06:45
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I once had a student do the following: Slowed down to up speed ,pulled the nose gently up, promptly rolled towards 60 plus deg,THEN applied full rudder!
YeeeeeHaaaa, did she ever roll!!
On our back before I could say DONT!
It doesn't prove anything because simulation is programmed on the data package given by the manufacturer. If you do some stunts which the test pilot hasn't, it may be good fun but it has no authenticity. That is not necessarily what will happen in real aircraft. From training point it is not only a waste of time it is also negative training and the conclusions are dangerous. The present simulators are not realistic of even deep stall which pilots have induced forget about other nonsense.
Now coming to the OP. When you don't apply rudder as in OEI in air or while removing the offset in strong crosswind landing if you observe on the flt ctl. page the spoilers deploy to prevent roll.

Last edited by vilas; 17th Mar 2018 at 02:05.
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Old 18th Mar 2018, 09:33
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Well,

I can only be thankful to all of your contributions in this thread. I keep learning every time I post here at PPrune :-)

a Big Thank You!
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