Problems in a commercial flight

C J Campbell writes:

The fact that he is right once in awhile is no indication that he knows
what he is talking about.

He is right more than just once in a while, and it is self-evident that if he
is right, he knows what he is talking about, since the chance of a random
answer being correct is exceedingly small.

He is not a pilot. He is a flight-sim guy.

That's the part that irritates you. Unfortunately, it has almost nothing to
do with knowing what one is talking about, despite a widespread misconception
to the contrary. Another example of credentialism. People who cannot depend
on an unambiguous distinction between knowledge and ignorance resort to
credentialism to maintain artificial separations.

Even Mxs should be able to learn something. But what he says should in
no way be considered reliable.

Exactly the same can be said of pilots.

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Dave writes:

There are also a couple of other guys I know of who could answer
this question, probably better than anyone here....

One is a designer of autopilots, the other is an aeronautical
engineer....

....neither is a pilot, nor has any interest in becoming one...

So, I guess many here would chastise them if they posted their
opinions here, because they are not "pilots"...

No doubt. There are many specialties in aviation, but I note that pilots seem
unusually prone to believe that they know _everything_ about aviation, even
though that is manifestly impossible, and even though, in fact, pilots only
learn what they need to know to fly (which is only a tiny part of aviation
knowledge).

On some occasions, I've had a terrible time convincing pilots that 90-degree
banks are impossible in coordinated turns, or that all turns involve
continuous lateral accelerations.

Many people learn what they know by rote, since this is much easier than
learning theory and inductively reasoning forward to specific knowledge.
Those who learn by rote don't realize that their learning is only one
interpretation of an underlying theory, and other interpretations are just as
valid.

Examples I've seen here are arguments about neutral trim and the way trim
works, or stall speeds.

I try to learn the theory when I can (except when it gets heavy into math--I
hate math). Theory leaves you better equipped to handle the unexpected than
rote learning does.

But, I guess that all works out, because Bombardier PAYS THEM BOTH
VERY WELL for their thoughts/opinions/ideas.

But, alas, like MX, they are not pilots..

So they are rich, but they can't climb into the treehouse. I daresay that
does not upset them.

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A rarity! My killfile must have bitten the dust with last reformat. Alas.

Mxsmanic wrote:
The mistake made by pilots here is to think that these
sensations are 99% of flying, when in fact their importance varies with the
type of flying under consideration.

The counter-example being, of course, that even high-time regular
heavy-iron pilots find the loss of feeling in the control column in
modern fly-by-wire aircraft so disruptive and unnerving that the
engineers had to design systems to emulate them, leading someone more
prone to contemplation to perhaps consider kinesthetics more important
than not.

They see everything from the cockpit of a Cessna...

Whereas, one points out, you have not even seen that.


It's painfully obvious that many of the pilots
here are low-time, small-aircraft pilots. Everything they say reflects this
viewpoint.

Why say that? Provide some examples, lest you fall into your own trap of
incompleteness in objective.

Most of them only _know_ about the plane(s) they fly. They don't know about
other planes, so they don't care about them.

Perhaps, again, that other pilots in the group actually do know little
of the specific aircraft, and choose to refrain from making
pronouncements and edicts of procedure and performance, based on the
knowledge of their ignorance, instead of barging into threads where they
would only succeed in mucking things up with incorrect information and
speculation.

They think that knowing the fine details of control pressures in a Cessna is
vitally important, but when I point out that many large aircraft don't work
this way at all, they dismiss that as unimportant. But it's not unimportant
to an Airbus pilot.

See the first above.

Some people have resources, and others don't.

Some understand how to live within their means while enjoying their
passion, and others simply look in from the outside and stir the pot in
the hopes of becoming a part of the community.

Some do, some don't. Some stop half-way and then pretend about the rest.

And yet others pretend about it all.

Provide the correct explanation, then.

Provided by other posters, which that hypothetical contemplatieur would
note you have not chosen to respond to, and that is: positive stability
brought on by wing dihedral (which, one also notes, is a feature of BOTH
Boeing and Airbus wings: why make an active system to compensate for
what can be designed out with passive engineering?).

Simulation removes part
of the need for imagination, so simulation is much less pretending than
non-simulation.

Simulation allows for the so-called "suspension of disbelief", which
necessarily denotes that the participant recognizes and properly
attributes the qualities and failings of such "simulation" in the first
place.

---

Here we part with the third person (which, noted, you enjoy referring to
yourself with).

I have seen MANY knowledgeable, polite corrections and responses to
your assertions go un-heeded while you chose only to argue with those
who attacked you.

The fact that I do not reply to a post doesn't mean that I haven't read it or
understood it. It usually just means that I have no quarrel with it and no
further questions about it.

Netiquette demands at least a thank-you or acknowledgment of receipt.


Those who engage in personal attacks also tend to be those who give wrong
answers or incomplete answers or no answers, and so I press them for answers.
I press them for answers in order to compel them to
look at their opinions and decide whether they are really worth clinging to
when they cannot be substantiated. I consider this a public service.

Translation: I assault posters with incessant questions, even about
objective, immutable topics, in order to frustrate further conversation
or to provide some tangible ethical or moral response to which I can
cling and make incorrect, hurtful, baseless assertions. I consider
myself superior over all others, even those with a clearly higher
understand or better experience.

I've found that people have an
enormous tendency to believe what they want to believe, and it's an exercise
in futility to try to make them think more critically.

Found a mirror again?

Most of my information comes from other sources...

Of which you refuse to enumerate when issued questions or inquiry (which
inevitably leads to doubt of veracity).

Why? To spare the overinflated egos of a minority? Why would I say something
that is _not_ my understanding? How could anything I say (or anything anyone
else says) be anything _other_ than an understanding?

No, to spare the uninitiated of misplaced trust.

You fail to understand the difference between understanding and
knowledge (used in this vernacular). There is a fundamental dichotomy
between third-party repetition of information, and a statement of fact.
Even you must recognize that much of your writing comes off as though
you have real, first-party knowledge of a topic, when in truth you are
either re-stating another's or your own interpretation of subjective fact.

Thus, again casting doubt on your actual capability, which is not
assisted by your utter rigidity (or, colloquially, Ferrous Cranus).

http://redwing.hutman.net/~mreed/war...rouscranus.htm

TheSmokingGnu

TheSmokingGnu writes:

The counter-example being, of course, that even high-time regular
heavy-iron pilots find the loss of feeling in the control column in
modern fly-by-wire aircraft so disruptive and unnerving that the
engineers had to design systems to emulate them, leading someone more
prone to contemplation to perhaps consider kinesthetics more important
than not.

Except that this isn't true. Feel and feedback are not hugely important and
one can easily become used to their absence. Simulating them in a large
aircraft is mostly a matter of convenience for pilots--not necessity. Indeed,
since the "feel" varies greatly from one aircraft to another, irrespective of
whether or not it is real or simulated, the habituation to control feel isn't
very transferable.

Whereas, one points out, you have not even seen that.

It's only a tiny dot on the aviation landscape, and I don't consider it
important. Most pilots have never seen anything from most cockpits. That
isn't much of a handicap.

Why say that?

Because it's true.

Provide some examples, lest you fall into your own trap of
incompleteness in objective.

The obsessions with sensation and control feel, issues that are highly
specific to certain types of aviation (such as small aircraft). The
preoccupation with VFR and VMC over IFR and IMC. The cluelessness with
respect to complex avionics and navigation systems. The acceptance of engine
failures as an unavoidable fact of life (most airline pilots go through their
entire careers without ever seeing an engine failure). And so on.

Perhaps, again, that other pilots in the group actually do know little
of the specific aircraft, and choose to refrain from making
pronouncements and edicts of procedure and performance, based on the
knowledge of their ignorance, instead of barging into threads where they
would only succeed in mucking things up with incorrect information and
speculation.

Nothing prevents them from studying to reduce their ignorance.

See the first above.

See an Airbus.

Some understand how to live within their means while enjoying their
passion, and others simply look in from the outside and stir the pot in
the hopes of becoming a part of the community.

Some people have resources, and some don't. And enjoying a passion doesn't
necessarily have anything to do with joining a "community" (boys' club).

And yet others pretend about it all.

So I've noticed, but that is their prerogative.

Provided by other posters, which that hypothetical contemplatieur would
note you have not chosen to respond to, and that is: positive stability
brought on by wing dihedral (which, one also notes, is a feature of BOTH
Boeing and Airbus wings: why make an active system to compensate for
what can be designed out with passive engineering?).

The reason for using an active system is that it improves maneuverability.
The drawback is that the aircraft has a tendency to depart from controlled
flight if the computers fail. That's Airbus. It's not Boeing (as far as I
know, with respect to civilian aircraft).

Here we part with the third person (which, noted, you enjoy referring to
yourself with).

No, I was simply continuing the style of the posts to which I responded, to
reduce ambiguity.

Netiquette demands at least a thank-you or acknowledgment of receipt.

Netiquette is an illusion. And in any case, I'm not interested in courtesy
rituals. Those who require the ego boost of some expression of gratitude need
not reply. Sharing knowledge should be its own reward.

Translation: I assault posters with incessant questions, even about
objective, immutable topics, in order to frustrate further conversation
or to provide some tangible ethical or moral response to which I can
cling and make incorrect, hurtful, baseless assertions. I consider
myself superior over all others, even those with a clearly higher
understand or better experience.

No. That is the perception that some have of it, but they allow their
emotions to rule, which is a bad thing in itself. People who are slaves to
their emotions are highly vulnerable and easy to manipulate. It's not good to
have large segments of the population with this handicap.

Of which you refuse to enumerate when issued questions or inquiry (which
inevitably leads to doubt of veracity).

There is no need to enumerate them. Others can do their own research and
learn for themselves whether or not I'm right. It's surprising how rarely
they do this.

No, to spare the uninitiated of misplaced trust.

Why would anyone trust a name on a screen?

You fail to understand the difference between understanding and
knowledge (used in this vernacular).

Which vernacular?

There is a fundamental dichotomy between third-party repetition
of information, and a statement of fact.

No, they are independent.

Even you must recognize that much of your writing comes off as though
you have real, first-party knowledge of a topic, when in truth you are
either re-stating another's or your own interpretation of subjective fact.

I leave verification as an exercise for the reader. And if I seem to have
real, first-party knowledge of a topic, that may well be correlated with the
fact that I am often right.

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Mxsmanic wrote:
Except that this isn't true.

Do deny that airliners are fitted with artificial feel systems?

Because it's true.

Why?

The obsessions with sensation and control feel, issues that are highly
specific to certain types of aviation (such as small aircraft). The
preoccupation with VFR and VMC over IFR and IMC. The cluelessness with
respect to complex avionics and navigation systems. The acceptance of engine
failures as an unavoidable fact of life (most airline pilots go through their
entire careers without ever seeing an engine failure). And so on.

I still fail to see the specific examples I requested, but rather your
opinions and interpretations instead.

Also, do you feel that engine failures are such a rare occurrence that
they should be deprioritized in training and emergency procedure
(keeping in mind that vast number of reasons that an engine might fail)?

Nothing prevents them from studying to reduce their ignorance.

Ah, but even then they would have to say that they have merely studied
the surface issues, and still yet have no direct experience.

See an Airbus.

Seen, noted, observed wing dihedral, question remains unanswered.

So I've noticed, but that is their prerogative.

Ah, so you DO re-read your posts?

The reason for using an active system is that it improves maneuverability.
The drawback is that the aircraft has a tendency to depart from controlled
flight if the computers fail. That's Airbus. It's not Boeing (as far as I
know, with respect to civilian aircraft).

What maneuverability would be required? Certain posters here would have
us believe that civilian jets are hardly capable of the turns they make,
let alone any kind of extreme evasion; more to the point, why design
systems that fail catastrophically? Why not use a passive design that
cannot fail in any kind of practical sense, and which always returns to
center?

Sharing knowledge should be its own reward.

Can we list the antithesis, that suffering speculation is its own torture?

There is no need to enumerate them. Others can do their own research and
learn for themselves whether or not I'm right.

You could at least do the courtesy of leading them in the right
direction, since you consider this a service to the public. The listing
of sources is a time-honored tradition in any kind of academic or
educational capacity (to wit: theses, or indeed any kind of research
paper); I don't expect formal formatting, but even an informal list,
perhaps?

Why would anyone trust a name on a screen?

Why would anyone trust words on a page?

Which vernacular?

The one to which I was referring, within the present context, with
accompanying explanation and dissertation.

No, they are independent.

You /ARE/ familiar with the term "dichotomy", correct?

I leave verification as an exercise for the reader. And if I seem to have
real, first-party knowledge of a topic, that may well be correlated with the
fact that I am often right.

See the above sources. If you have practical first-hand experience,
by all means validate your evocations with a qualifier, so that people
(again, your deserving public) may more readily distinguish between
research and anecdote.

TheSmokingGnu

Mxsmanic wrote:
EridanMan writes:

They do not have too. They only need to get the aircraft close enough
for wing dihedral to do the rest. Its called a dynamically stable
aircraft design, and its been a cornerstone of aviation almost since
its inception.

Until Airbus came along.

Your pathetic ignorance continues to show. This one isn't even
related to your continual fantasy land.

Despite all the flight control systems in the fly-by-wire airbuses,
they still have positive stability. Now Boeing on the other hand
thought the 767 at first wasn't going to have positive pitch stability.
They spent a lot of time working with GE to develop active components
to control that. Fortunately as the design progressed it turned out
to not be necessary.

Further, it's not just fly by wire aircraft that have artificial
feel built in to them. Yes, in the case of FBW it's 100% artificial
but don't believe that a lot of time isn't spent on many aircraft to
get the control forces to feel right.

Mxsmanic wrote:
EridanMan writes:

Minor Harmonic oscillations in flights are a natural byproduct of the
dynamic stability of modern aircraft. The Autopilot has no part in
it.

Do these oscillations cause control surfaces to move by themselves? Are they
asymmetrical?

Sometimes, and yes.

Dutch roll and spiral come to mind, although they are not limited exclusively
to the roll axis.

Spiral is not an oscillation. Spiral is a departure from positive
stability when you push things too far.

If you get behind the yoke of a real aircraft, get it all trimmed up and
take your hands off (NO AUTOPILOT) and then shove hard on the yoke and
let go, you'll see either one of two things. It will either oscillate
back and forth through the trimmed flight eventually settling down or
it will very slowly return to trimmed flight by just bringing the nose
up.


No MX... it has nothing to do with the autopilot...

If the control surfaces are moving, either the pilot or the autopilot is
acting upon them.

Absolutely and totally incorrect. You should go read a introductory
pilots book section on flight aerodynamics.

If the corrections are asymmetrical, this would tend to
exclude the hypothesis of harmonic oscillations. Also, roll harmonics often
extend over periods of minutes in large aircraft and would not be obvious just
by watching the wing outside the window.

Now your an aerodynamics expert?

Mxsmanic wrote:

No doubt. There are many specialties in aviation, but I note that pilots seem
unusually prone to believe that they know _everything_ about aviation, even
though that is manifestly impossible, and even though, in fact, pilots only
learn what they need to know to fly (which is only a tiny part of aviation
knowledge).

And you profess to know everything even though you fly nothing.

On some occasions, I've had a terrible time convincing pilots that 90-degree
banks are impossible in coordinated turns, or that all turns involve
continuous lateral accelerations.

Of course you'll have a terrible time convincing people of that.

All coordinated flight involves is that the tail of the aircraft follow
the front in the flight path (this is confusing to most people primarily
because of the FAA's stupid pseudo-physics definition of it). There
is nothing that prevents coordinated 90 degree banks. In most aircraft
however, you're not going to be able to sustain that. Since you've
lost your primary lift source (the wings) because they now have their
lift vector perpendicular to vertical, to maintain altitude, you need
to get a little lift form unconventional places. This is usually done
by canting the fuselage a little bit. This almost always involves
a bit of non-coordination.

The secret of turning is not just that there is a lateral acceleration
(if that is all there was, you'd just start translating towards the
banked side rather than turning) but that the direction of that
acceleration is continuously changed .

I try to learn the theory when I can (except when it gets heavy into math--I
hate math). Theory leaves you better equipped to handle the unexpected than
rote learning does.

Then why do you fail to understand it very well/?

On Mar 15, 8:14 pm, Mxsmanic wrote:
writes:
Yes, they can.

No, they cannot, except under ideal conditions, and sometimes not even then.

But what do I know, I only fly tiny planes.

My thoughts exactly.

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Well, this tiny-plane-pilot can and have done so, and there are many
others.
Not that I liked it though.

-Kees

TheSmokingGnu writes:

Do deny that airliners are fitted with artificial feel systems?

Some are. But feel varies significantly from one aircraft to another.
Sometimes it is simulated just because pilots expect it.

Why?

I don't know why it's true.

Also, do you feel that engine failures are such a rare occurrence that
they should be deprioritized in training and emergency procedure
(keeping in mind that vast number of reasons that an engine might fail)?

I think they should be kept in perspective. Engine failures in certain phases
of flight are serious emergencies, and since they are so easy to practice in
simulation, there's not much reason not to do so. But at the same time, they
are extremely rare in large commercial airliners, so practicing them in excess
(to the detriment of practice in other, more likely emergency scnearios) is
probably not a good idea.

In small aircraft, the engines are so unreliable that engine failures must be
practiced. Ironically, there's no really good way to practice them, since
full-motion simulators for small aircraft are rare, and it's too dangerous to
practice true engine failures in a real aircraft (setting an engine to idle
doesn't count).

Ah, but even then they would have to say that they have merely studied
the surface issues, and still yet have no direct experience.

There isn't any specific limit to the depth of study one can undertake. Both
study and experience are legitimate ways to learn; both can lead one to attain
the same goals.

Seen, noted, observed wing dihedral, question remains unanswered.

Some Airbus aircraft are designed to be unstable, under the assumption that
computers will keep them flying straight and level.

What maneuverability would be required?

That's a good question. You'd have to ask Airbus. I can't think of any high
maneuverability requirements for airliners.

Certain posters here would have
us believe that civilian jets are hardly capable of the turns they make,
let alone any kind of extreme evasion ...

They are capable of much more than is usually requested of them. This being
so, going beyond that seems illogical. But I've never seen much logic in
Airbus--after all, it's a political organization.

... why design systems that fail catastrophically?

Systems fail catastrophically when they are _not_ designed. Catastrophic
failure modes are characteristic of unanticipated exceptions in digital
systems.

Why not use a passive design that cannot fail in any kind of practical
sense, and which always returns to center?

That cannot be done with digital systems. They only fail safe in modes that
are anticipated in the design; in other modes, catastrophic failure is more
likely.

You could at least do the courtesy of leading them in the right
direction, since you consider this a service to the public.

That would not be verification.

The listing of sources is a time-honored tradition in any kind of academic or
educational capacity

Yes, and it is vastly overrated in consequence. Many incorrectly assume that
the mere presence of references somehow validates whatever uses them.

Why would anyone trust words on a page?

Exactly.

You /ARE/ familiar with the term "dichotomy", correct?

Yes. And I don't even need to look it up. Your use of the term puzzled me,
but it was part of a pattern I noticed in the entire post, so I let it slide.

See the above sources. If you have practical first-hand experience,
by all means validate your evocations with a qualifier, so that people
(again, your deserving public) may more readily distinguish between
research and anecdote.

They need to do their own research.

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