Originally Posted by
arcniz
True, indeed. Software generally does not fail-soft. The heavy dependence on software that is 'undocumented' and inaccessible to all but a select-few company insiders means no accountability, no transparency, and no independent verification of the critical control processes and underlying assumptions that operate most functions in modern aircraft.
This comment betrays a lack of understanding of safety critical software systems design. I wouldn't expect you to have an understanding of same unless, like myself, you had spent several years studying the topic. If you have not done so then perhaps you could avoid making ill informed sweeping statements about my profession.
Software systems can be and are designed to fail in a deterministic state and furthermore the hardware systems on which they run are designed likewise. The degree of redundancy in a FBW flight control system is typically an order of magnitude greater than for a hydromechanical system.
Safety critical systems are never written in an "undocumented and inaccessible" way. Large projects often have dozens or hundreds of contributors all working within a far more controlled process than that used for business applications. Many systems are subject to external scrutiny and certification. Where redundancy is required it is not unusual to use two different teams (sometimes different companies) to develop the exact same application - a development approach originally pioneered by NASA.
I would be more concerned by many of the mechanical and electrical systems than I am about the software. Pilots tend to blame every glitch "on the computers" when in reality the vast majority of issues are caused by transducer failures or even a simple misunderstanding of how to use the system. Such problems can equally affect hydromechanical aircraft. As far as I'm aware there has never been a FBW failure in a commercial aircraft that has resulted in loss of critical control systems. The number of tech problems due to software are totally eclipsed by mechanical and electrical problems.
FBW software systems are known to have saved aircraft, but are yet to be proven causal in any production hull loss. That makes our record infinitely better than almost every other aircraft system.
Just imho.