

Air France Flight 447: The Paradox of ‘Simplicity’ - old-gregg
http://trueslant.com/milesobrien/2009/06/10/the-paradox-of-simplicity/

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ilitirit
Apparently idea that computers exclusively run the AirBus has been debunked:

 _[...] THE SYSTEM WILL NOT FIGHT THE PILOTS. The system just gives me the
best the airplane can do at the moment without me having to stop and consider
my conditions.

If I as the pilot deflect the stick left, if the autopilot is engaged, it will
be disengaged for me. The load factor is considered and the airplane will
begin a maximum-rate roll in the direction I deflected the stick. I keep
holding the stick and the airplane will keep rolling up to the limiter. That's
when Normal Law is active. If we're in Alternate or Direct law, there is no
roll limit and I can roll the airplane onto its back and crash it if I desire.
[...]_

[http://tech.slashdot.org/comments.pl?sid=1261521&cid=282...](http://tech.slashdot.org/comments.pl?sid=1261521&cid=28261799)

~~~
sfphotoarts
But this isn't what the article is asserting. They are not saying the
autopilot couldn't be overridden. The article is saying that it appears that
while flying into a very bad storm the pilots disengaged the AP and attempted
to make an emergency, beyond-limits, turn, which the plane 'allowed', and then
at some point after that the disaster struck (structural failure, for
example). Whatever happened, did so before (presumably very busy) pilots could
radio anything.

The article possible alludes to maybe pilots used to making very small changes
to the very capable AP might loose their skills over time, but that's like
saying cruise control does the same to drivers (and it might, I have no idea)

~~~
ilitirit
I didn't get that from the article. From what I understood, the point he was
making was that the AP systematically relinquishes control of the plane as
conditions deteroriate. By the time human pilots get hold of the plane, the
conditions are for too difficult for them to handle. My issue with the article
is the implications he makes. He compares the Boeing to the Airbus and then
talks about the philosophy behind the Airbus. As I replied to sweetdreams, his
statements about the plane (eg. _Who's in charge here?_ ) are misleading. It's
as if he's saying that pilots are in full control of Boeing, but not in an
Airbus.

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dmfdmf
I used to design nuclear reactor control systems. One of the never ending
debates was how much to automate and how much to leave for the reactor
operators (or pilots in this case). There is no clear cut answer since with
today's technology its possible to automate everything. However, if you over-
automate you get a detached, bored reactor operator who suddenly has to take
control if things go wrong. On the other had human error is one of the most
common causes of industrial accidents and plane crashes. Tough engineering
choices.

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deafmetal
Miles O'Brien is consistently surprising in his depth of thought. (Or depth of
assistants, i'm not sure...)

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drewr
I don't understand why a thunderstorm would have affected this plane. Wouldn't
it have been cruising by that time at an altitude immune to weather? Perhaps
this was discussed in another thread; I haven't been following the discussions
too closely.

~~~
boundlessdreamz
Nope. The altitude it was flying at was not immune to weather. Also the
thunderstorm had

* Strong updrafts of wind * Heavy moisture content which was sucked up from the ocean and which turned to ice and hail

Read about the coffin corner by the same author
[http://trueslant.com/milesobrien/2009/06/08/the-coffin-
corne...](http://trueslant.com/milesobrien/2009/06/08/the-coffin-corner-and-a-
mesoscale-maw/)

What I don't understand is, if they lose altitude because of being at the edge
of the corner, wouldn't the pilots be able to steady the aircraft at a lower
altitude?

~~~
designtofly
You're correct in that being in the "coffin corner" is not dangerous in
itself. In straight-and-level flight, if you go any faster, the extra drag
will slow you down. If you reduce your thrust from your engines, you will slow
down and lose altitude.

The problem comes about if you enter into any unusual attitudes, which is
certainly possible in severe turbulence. The most important part would be a
safe recovery to straight and level flight. An unusual attitude can put you in
a situation where you overspeed the aircraft (e.g. nosedive). Above the
maneuvering speed of the aircraft, you must be very careful to regain control
without overstressing the airframe.[1] If your speed sensor(s) are giving you
or the autopilot faulty readings, it would be very difficult to know the
safest way to regain control of the aircraft after being put into an unusual
attitude due to turbulence.

[1] American Airlines Flight 587 crash (NY, 2001) taught us that even below
the manuevering speed of the aircraft, the airframe can be overstressed due to
dynamic loads from pilot control inputs.

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ErrantX
By far one of the best articles posted on here regarding the tragedy. food for
thought?

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TweedHeads
There were bomb threats days before the disaster.

A fact that can not be denied even if it costs me another 50 karma points.

[http://www.google.com/#hl=en&q=flight+447+bomb](http://www.google.com/#hl=en&q=flight+447+bomb)

~~~
jonknee
There are threats every day. The fact that no one has claimed responsibility
makes a terrorist attack very unlikely.

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stcredzero
The description of Airbus Fly-By-Wire reminds me of programming with Eclipse!

EDIT: Okay, you thin-skinned Eclipsers, note that while the Airbus has a
horrendous failure mode in extreme conditions, according to the article, it's
a much more efficient way to fly a complex aircraft, and much less prone to
human error.

The point is, you still need to know your craft, for when the automation fails
you!

