PPRuNe Forums - View Single Post - How safe is (airbus) fly by wire? Airbus A330/340 and A320 family emergency AD
Old 19th Dec 2012, 20:42
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DozyWannabe
 
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Even with the "button" activated, the T7 remains computer- (or at least electronically-) controlled. The only difference is that the protections are disabled and some of the functions are bypassed. Airbus's temporary solution of switching off ADRs will essentially give you the same result.

It's not an ideal situation, certainly - but at least the problem has been diagnosed and a fix is forthcoming. I think this only affects a relatively small number of the current fleet.

Additionally, those calling for a manual switch to Direct Law demonstrate either a lack of understanding of, or in some cases wilful disregard for, the way the system was designed (by a team that included pilots) to operate. Hard protections of the kind identified as an issue in this case are disabled in any law outside of Normal and the aircraft will follow any command given by the pilot in this circumstance. Alternate Law is far closer in response terms to the handling characteristics Airbus FBW pilots encounter on a daily basis and as such makes far more sense than Direct in terms of keeping aircraft behaviour as consistent as possible in an abnormal situation.

It's also worth pointing out that in the situation described in the EAD and OP, Alpha Prot will not suddenly order a fistful of control input.

Last edited by DozyWannabe; 19th Dec 2012 at 22:34.
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