

Air France crash 'due to pilot & technical failure' (Final report on 2009 crash) - ColinWright
http://www.bbc.co.uk/news/world-europe-18720915

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rubyrescue
The fact that airbus AVERAGES the control inputs, with no indication of
conflicting inputs, when one pilot is pulling back and one pilot is pushing
down is just a perfect example that even at the most critical points, where
the stakes are the highest, we as engineers and designers fail to think
through the implications of bad design.

~~~
cjrp
But would adding an extra caution light / sound to the already-stressful
situation have helped? I agree that averaging the inputs seems like an
imperfect solution, but what would the alternative be... ignore both or ignore
just the Captain/First Officer's inputs?

 _edit_ : Re: physically-linked controls (à la Boeing), with one pilot pulling
back as hard as he can Vs. the other pushing fwd, isn't the result still
(approximately) an average of the two inputs? Obviously they'd feel that the
controls weren't moving, but that could be attributed to a number of factors
(e.g. icing of the control surfaces).

~~~
rubyrescue
an alternative would be to move the sticks together, the way non-fly-by-wire
planes work.

~~~
rogerbinns
They could also make the sticks move together even on fly by wire planes
(Boeing does it) using force feedback. That is one thing that Airbus really
should have done instead of providing no physical feedback. The expectation is
that you would use your eyes instead, but the visual channel is already
heavily loaded.

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kenver
There was an interesting discussion on here about this nearly a year ago,
after the data recorders turned up.

<http://news.ycombinator.com/item?id=3327202>

~~~
joezydeco
That HN submission links to a Popular Mechanics article that goes over the
last 10-12 minutes of AF447's voice recorder, line by line. It's a very
detailed read and worth the time. It will also chill you to the bone.

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crikli
I wrote an explanation of how flight instruments are powered that is germane
to this discussion (and IMO helps clarify what happened).

<http://news.ycombinator.com/item?id=2595230>

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mtgx
I can't imagine the horror of knowing you're going to die in a couple of
minutes when the plane crashes.

~~~
viraptor
Fortunately you can't be sure. On average around 2/3 people die in a plane
crash and you can improve your chances a lot by sitting in the right place
(near the aisle, a couple of rows from the back is safest if I remember
correctly) with seatbelts on. While still terrifying, I was surprised about
those chances of survival and so were most of the people I talked to about it.

~~~
finnw
Really? I can understand how the front of the aircraft (as it collapses) can
cushion the impact if you are in that position, but after that you still have
to avoid being killed by hypothermia or drowning (if you hit water) or fire
(if you hit land.)

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gouranga
The root cause was Technical failure, not pilot error. The instruments were
wrong and the burden of accuracy on such a technically complicated machine is
on the aircraft.

But that's too easy to sue for so the manufacturers of the systems press to
blame the dead crew.

This is standard corporate culture.

~~~
raldi
The fact that the pilot ignored the continuous audible "Stall! Stall! Stall!"
alarm and kept the control stick pulled fully back (the opposite of what you
want to do in a stall) suggests to me that it's legitimate to place some of
the blame on human error.

~~~
jt2190

      > The fact that the pilot ignored the continuous "Stall! Stall! Stall!" alarm 
      > and kept the control stick pulled fully back
    

The fact is that the black boxes recorded this behavior. Can we be 100%
certain that the copilot actually did this? My concern is that we're still
trusting the output of a system that has proven to be suspect.

~~~
raldi
Other than the airspeed sensors freezing up, I'm not aware of any other known
malfunctions. What makes you say the system was "proven to be suspect"?

~~~
jt2190
I'm quoting Wikipedia's summary of the Report:

    
    
      * The stall warning deactivates by design when the angle of attack measurements
        are considered invalid and this is the case when the airspeed drops 
        below a certain limit.
      * In consequence, the stall warning stopped and came back on several times 
        during the stall; in particular, it came on whenever the pilot pushed forward 
        on the stick and then stopped when he pulled back; this may have
        confused the pilots.
      * Despite the fact that they were aware that altitude was declining rapidly,
        the pilots were unable to determine which instruments to trust: it may have
        appeared to them that all values were incoherent.
    

Personally, I'm not sure whether to believe that the copilot simply made an
amateur mistake .

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raldi
Can we clarify the title to " _2009_ Air France crash 'due to pilot and
technical failure'"?

The way it is now makes it sound like there was another crash.

~~~
daeken
The crash was in 2009. This story is from 2012 -- today, in fact.

