Re: OT: Ladies and gentlemen, welcome to Hamburg, we will try landing again shortly.

On a sunny day (Mon, 03 Mar 2008 13:42:32 -0800) it happened Tim Wescott
<tim@xxxxxxxxxxxxxxxx> wrote in
<KY6dnaQHZI4n7VHanZ2dnUVZ_jadnZ2d@xxxxxxxxxxxx>:

Well I do not understand the last sentence, my view is that they should not
fly in this weather, but my view is also that robots (or robotics) have
a better attention span, can make many corrections per second, and possibly
could have kept the plane more level (he is wobbling all the way).
Depends a bit how those robotics were designed of course :-)

Modern fighters have instable flight, and correct settings many times a second,
so the technology is there.

My point in the last sentence is that since _I_ couldn't do nearly that
well, I'm not going to chew the pilot's ass. At the very least I'm not
going to do so unless I hear from more than one transport pilot who's
really looked into it and who points out specific violations of
recognized conduct.

OK.


I suppose I could criticize the decision to land at all, but (a) I'm
still not a pilot, and (b) I've seen videos from other airports
(Singapore, I think) where crossed-up landings like that are _routine_,
because of the prevailing winds and the direction of the runway.


Well a bit of background, 'orkaan' (Dutch) 'hurricane' (English) warnings
were present in the media from last Friday for Saturday and the weekend,
with predicted wind speeds and warnings to stay inside etc.
The low pressure zone hit Germany from the North Sea (after passing by here),
and if you use google maps you will see Hamburg is just a bit south of that
and in the path of the hurricane.
That airport should have been closed, and any transatlantic flights would
have gotten the weather at Hamburg and diverted.
Maybe people died in that storm, trains no longer ran because trees over
the rails:
http://edition.cnn.com/2008/WORLD/europe/03/01/europe.storm/index.html


There are limits to what an automatic control system (your 'robot') can
do. Regardless of the capability of the pilot or controller, the
aircraft will still fly within the capabilities of the airframe and
control surfaces; some wobbling in gusty conditions will always be
there, and unexpected gusts will cause unexpected aircraft behavior.

Sure, and as Joerg pointed out, there is a limit what you can control.


In fact the X-29 fighter, which was intentionally designed from day one
to be dynamically unstable in subsonic flight, wouldn't have had
acceptable control margins for a 'real' fighter. Why? Because the
between the speed of the instability and the bandwidth of the actuators
and sensors, the control system _could not_ achieve acceptable phase and
gain margins. The control surfaces simply could not be moved fast
enough to maintain the stability that would be required for anything but
an experimental fighter.

Here are some concepts described, like rapidly rotating airfoils that will be tested
perhaps in future fighter designs:
http://www.airpower.maxwell.af.mil/airchronicles/apj/apj88/spr88/siuru.html
Clearly the pilot can become a weak link in cases of huge G in fighters.

But did you read about that flight to Hawaii last weak that did overshoot the destination,
and pilots were thought to have fallen asleep?
They woke up it seems, and returned, but you can run out of fuel that way
very easily.
We do not read about half the 'near misses' or 'near disasters' due to pilot
error, because why should they ruin their own career?


The only advantage that I could see to a robotic pilot is that with the
right sensors it may be able to sense gusts quicker than a human with
his *** glued to a chair. On the other hand, when stuff happens to the
aircraft that are beyond the range that was predicted by it's designers,
it's nice to have someone in the hot seat who can re-think the control
rules on the fly (as it were).

In case of a passenger plane those stresses are well known.
The stresses on pilots, such as lack of sleep, alcohol, personal
circumstances (one pilot died last weak on a flight, the co-pilot landed the plane),
would be avoided by 100% computer control.


Modern jet liners have fly-by-wire, although the civilian transport
industry currently avoids stability augmentation in favor of
guaranteed-stable airframes. You may be able to do something with shear
detectors on wingtips that are coupled to the flight control system --
this sort of thing gives you an even chance of combining the strengths
of pilot and the control system vs. combining the weaknesses, so it's
not something you want to just jump into.

True, but a pilot on board who almost never actually flies how
well would he do in an emergency?
Better have a backup computer.
.

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