Originally Posted by
CONF iture
Automation did not drop enough : Leave the trim alone and we have a different game to play.
Then include it in the wrongs ... Why not ?
First:
If this and other LOCs were down to pilots who could handle a conventional aircraft perfectly well in the same circumstances but were constrained/prevented/confused by the airbus flight control laws, then I'd agree - ditch Alt laws and drop straight to direct. Give the crew the conventional aircraft if/when things start going wrong.
...but I don't think the above is a correct assumption. There's a subset of pilots (probably including those who care enough to follow accident threads on here) who would handle direct law just fine (or better), but is that the majority when I also see comment after comment along the lines of
Machinbird's "compare what we learned about actual aircraft handling compared to what is presently being taught in the puppy mills, it is night and day".
Second:
I don't think stopping autotrim would have affected this accident. I know you've argued that had the nose gone down they'd have diagnosed the stall, but I'm not so sure. When the a/c
did pitch down in stall what was the reaction ? Pull-up, hard. If you're already prepared and briefed for stall in the sim, the nose drop is going to be obvious, but if you think the a/c isn't responding right (which looks like an issue in roll at least even before the stall) and you're pulling back and the a/c suddenly drops the nose, what will you do ?
Third:
Changing something one way to "fix" one accident may make things worse in other cases and end up killing more people. We should look at all the LOC incident history not just this one. I've done some looking, though not in any way a systematic survey, in what I've read the common factors were:
Airbus: no. FBW: no. Sidestick: no. Trim / AutoTrim: oh yes. Time after time. Not every incident, but probably a majority - and much more common factor than the others.
But what is the typical problem with trim, what's its MO when it kills ? Looks to me like it's trim-up before stall, autos drop out, trim not managed by crew then contributing to the upset and/or preventing the recovery. Exactly the opposite of 447 - which looks like the odd one out.