Originally Posted by
Mr Optimistic
Bear: there is no reason to think the software was at fault in this instance is there? Necessarily limited perhaps, but isn't it more to do with the presentation of information which is at issue ?
Agreed, and I hope I'll be forgiven here for stating things more bluntly.
Originally Posted by
bearfoil
Allow me. A casual view of the history of the Airbus leaves a few undigested morsels. Question the electrics, and the software side gets indignant. Some flyers get indignant that the a/c seems "arrogant" (sic).
An airplane cannot be arrogant, and software cannot be defended when it is garbage.
After all this time, if there is a remotely valid question raised (There are), something is wrong with the approach.
The honeymoon was over long ago, and this airplane has worn long pants for years. To be able to get away with calling it a "work in progress" at this point is beyond absurd.
Training? Confidence? User friendly? Who gives a crap, Fix it.
Bear, I deliberately stepped back from this thread when I realised a few days ago that all I was doing by posting was repeating myself - and in doing so getting far more worked up than I should. So unless you have new information may I respectfully request that you consider the same?
Now, if you'll allow me to refer to your points:
- No-one on the "software side" has become "indignant" in this thread. You have a few skilled electrical engineers (not all of whom are familiar with the system's design) positing theories, but that's about it.
- Flyers are allowed to think what they like - and they seem to be about fairly divided on their opinions towards automation (though understandably some are a little short on the facts and some are unable/unwilling to understand certain aspects of it).
- Sometimes they get the presence of automation confused with how some airlines are using that automation - and how it affects their jobs. Again, this is understandable, if sometimes a little frustrating
- At no point has any piece of evidence been raised that points to a failure in the aircraft systems, over and above the loss of airspeed information. What little we have suggests that it was behaving as designed.
My personal opinion, for what it's worth, is that all this talk of control laws will turn out to be a red herring. What sounds complicated on paper is in fact not all that complicated. With all systems functioning, you are in Normal Law. When certain systems components fail, you are in Alternate Law. If basic flight data becomes unavailable, you are in Alternate Law 2 (which for the sake of argument should be thought of as Alternate Law without protections).
In Alternate Law 2 the pilots have complete control over all aspects of the aircraft, though you're commanding pitch and roll rate unlike in Direct Law which commands deflection. In short -
the pilot is in charge and the computers are specifically programmed to do whatever the pilot asks.
Autoflight is already out, so the computers cannot command anything that the pilot is not already commanding. In this law, Autotrim will answer commands from the sidestick, if the sidestick remains deflected past the limit of elevator authority. In this aspect it is not unlike the old DLC system in the TriStar, which linked all flying surfaces to the controls to better stabilise the aircraft. Autotrim can be disabled in this mode simply by grabbing the trim wheel and moving it, just like in any other airliner - if this aspect is not being trained by airlines then it is a *serious* omission.
So - what we have so far is the aircraft's trajectory during the accident sequence, and a set of "point-in-time" status reports of what was going on and being said in the flight deck. Other than that we know *nothing* - even CONF iture is holding back on blaming the aircraft, which is almost unheard of (even if he is making up for that by bashing the BEA)!
Take out all this discussion over laws and automation and what you're left with is a crew over the ocean in the middle of the night (low circadian time and - perhaps even more importantly - no visible horizon or external reference) who suddenly find all airspeed information gone, a plethora of warnings they've got to figure out and a few minutes to make the correct choice. This is not the first time it's happened, and it's not the first time it's killed people.
Right, now back to radio silence on this thread for a bit...
@peplow - The ADI (artificial horizon) would have given them enough attitude information to work with - and even with a working AoA indicator, experienced pilots have failed to heed it in this situation.