Originally posted by Schwartz
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In order for this to occur, the SEC's must be in control of pitch (both ELAC faulted) on the ground AND the LGCIU's have to be sending opposing air/ground signals to them (the left and right MLG have to be in a very different state of compression for at least one second.)
In other words, this requires the aircraft to begin the take-off roll with zero ELAC's functioning and then experience an asymmetrical "bounce" large enough to make that possible BEFORE rotation.
How could that ever happen in a revenue flight?
1) You could dispatch a flight with a single functional ELAC. Then during the takeoff roll, the remaining ELAC would have to suddenly fault (why?) AND then you need to lift off, drop back hard on the runway, asymmetrically AND then decide to continue the takeoff. That would be a fantastically bad day.
2) You could engage in a very late go-around (perhaps due to some runway incursion) with both ELAC's already in a faulted state (perhaps after being dispatched with a single ELAC and it failed during the flight), touch down hard to get the asymmetrical bounce, THEN land and THEN attempt to lift off again. That would be a fantastically bad day.
3) You could have an improperly maintained stabilizer override mechanism malfunction, undetected, and then do what these guys did. Why would you ever do that on a revenue flight?
And lastly, after the Airbus software upgrade, even then it won't happen.
I agree that complexity brings new risks (the 737-MAX is a perfect example of this) but it seems the Airbus engineers thought things out very, very carefully. The only FBW flight control failures I'm aware resulting in loss-of-control were similarly phenomenal in nature and thus nearly impossible to predict or defend against.
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