G430 Display/Numbers or Pictures?

In article . com,
"Andrew Sarangan" wrote:

Jose wrote:
The CDI display
on Nav1 is pretty useless because it is not a real CDI.

I don't know what that means. When I use the CDI display (page 1 on the
nav screen) I find it quite effective.

Jose


That means you are not using the CDI to its full potential. A CDI gives
a _course_ to turn to, not a left/right indication. For that to work,
you need a full circle of numbers around the CDI.
If you have never encoutered this concept before, you should read this:
http://www.sarangan.org/aviation/art...or-article.pdf

Andrew,

I just read your article. The big problem with it is that it equates
"heading" and "track". For example, you talk about an OBS set to 210, with
a centered needle and a "FROM" (downward-pointing arrow) indication and say:

"030 lies in the direction of the station. This is the heading we need to
fly to track the course towards the station."

I'll agree that turning to a heading of 030 is a reasonable first estimate
until you figure out the right WCA, but as written, the article is just
plain wrong.

I also take exception to the general tone of the article, which is that the
CDI is a wonderfully designed instrument and whole generations of pilots
and instructors are idiots for not using it the way it was intended to be
used. It certainly is a cleverly designed instrument -- it's the best that
the brightest minds of the aviation world could come up with using the
technology of 50 years ago. You say things like:

"Given the simplicity of this technique, it is somewhat mysterious why this
is seldom taught during flight training".

There's really only two possible answers. One is that we're all idiots,
the other is that it's not really as simple as you make out. You think
it's simple, but, you're a college professor with a PhD. How many of your
students have this level of education?

You say:

"There might be a lesson in this. Some things are better left the way they
are. The VOR system might be a 50-year old technology, but it is one of
the greatest inventions in aeronautical navigation. It is really too bad
that we won¹t have them for much longer"

I can't disagree more. People vote with their feet. The VOR/CDI combo WAS
indeed a great invention. It was better than the ADF because it presented
better information to the pilot. The VOR/HSI was an improvement on that,
for the same reason, but never really penetrated the GA market because of
the high cost. The moving map GPS is an even bigger step up in
presentation (although the UI's for programming them still pretty much
suck).

People's brains have evolved over thousands (millions?) of years to process
visual information. If we're going to have good interfaces to people's
brains, we need to present them with information in the way those brains
are used to processing it. 50,000 years ago, some ancestor of mine could
look at the tree he was walking towards and understand that if he wanted to
get to the tree, he needed to turn left. Given a choice between inventing
technology to match my 50,000 years of visual experience, or training my
brain to understand what a 50 year old electro-mechanical gizmo is telling
me, I'll go with the GPS moving map.

Roy Smith wrote:
In article . com,
"Andrew Sarangan" wrote:

Jose wrote:
The CDI display
on Nav1 is pretty useless because it is not a real CDI.

I don't know what that means. When I use the CDI display (page 1 on the
nav screen) I find it quite effective.

Jose


That means you are not using the CDI to its full potential. A CDI gives
a _course_ to turn to, not a left/right indication. For that to work,
you need a full circle of numbers around the CDI.
If you have never encoutered this concept before, you should read this:
http://www.sarangan.org/aviation/art...or-article.pdf

Andrew,

I just read your article. The big problem with it is that it equates
"heading" and "track". For example, you talk about an OBS set to 210, with
a centered needle and a "FROM" (downward-pointing arrow) indication and say:

"030 lies in the direction of the station. This is the heading we need to
fly to track the course towards the station."

I'll agree that turning to a heading of 030 is a reasonable first estimate
until you figure out the right WCA, but as written, the article is just
plain wrong.

I also take exception to the general tone of the article, which is that the
CDI is a wonderfully designed instrument and whole generations of pilots
and instructors are idiots for not using it the way it was intended to be
used. It certainly is a cleverly designed instrument -- it's the best that
the brightest minds of the aviation world could come up with using the
technology of 50 years ago. You say things like:

"Given the simplicity of this technique, it is somewhat mysterious why this
is seldom taught during flight training".

There's really only two possible answers. One is that we're all idiots,
the other is that it's not really as simple as you make out. You think
it's simple, but, you're a college professor with a PhD. How many of your
students have this level of education?

You say:

"There might be a lesson in this. Some things are better left the way they
are. The VOR system might be a 50-year old technology, but it is one of
the greatest inventions in aeronautical navigation. It is really too bad
that we won¹t have them for much longer"

I can't disagree more. People vote with their feet. The VOR/CDI combo WAS
indeed a great invention. It was better than the ADF because it presented
better information to the pilot. The VOR/HSI was an improvement on that,
for the same reason, but never really penetrated the GA market because of
the high cost. The moving map GPS is an even bigger step up in
presentation (although the UI's for programming them still pretty much
suck).

People's brains have evolved over thousands (millions?) of years to process
visual information. If we're going to have good interfaces to people's
brains, we need to present them with information in the way those brains
are used to processing it. 50,000 years ago, some ancestor of mine could
look at the tree he was walking towards and understand that if he wanted to
get to the tree, he needed to turn left. Given a choice between inventing
technology to match my 50,000 years of visual experience, or training my
brain to understand what a 50 year old electro-mechanical gizmo is telling
me, I'll go with the GPS moving map.


You are right that I did not address the wind correction aspect.
However, that is not too difficult; just take a heading on the side of
the needle. I did not want to confuse the concept by adding too many
variables.

I think you are being way too sensitive to be insulted by this article.
My intention was to tell pilots that there is an alternate method
instead of the traditional left/right interpretation. I am not trying
to sell any product or service. I am simply passing on some useful
information that I have had the good fortune to learn from others. If
you don't like it, I will give you a full refund :-)

I did my instrument rating using the left/right interpretation and I
found it to be very confusing. In fact I busted my IR checkride because
I turned left instead of right on a VOR holding entry. Then I read an
article that illustrated this technique and life has never been the
same. It is wonderfully useful when being vectored for a localizer or
VOR approach.

I never said moving map was not useful. I use it all the time on my GNS
430. What I meant by "somethings are better left the way they are" was
"the VOR+CDI is better left the way they are instead of trying to mimic
the CDI with an electronic bar scale". I did not mean that VOR is
superior to GPS. If it came across that way, I apologize. That would be
absolutely crazy. I am a big fan of GPS, and I have been messing with
GPS in aviation for at least 10 years. I will be one of the first to
vote with my feet when it comes to GPS.

Actually, it is not that mysterious why more instructors don't teach
this technique. It is just that they are not aware of this method.
Simply pointing that out should not be an insult. I am sure I don't
teach some things that I don't know about, and I am sure you do the
same.

"Andrew Sarangan" wrote:
I think you are being way too sensitive to be insulted by this article.

I didn't mean to imply that I was insulted. My apologies if it sounded
that way.

I did not mean that VOR is superior to GPS. If it came across that way,
I apologize.

Well, it sounds like we're even :-)

That would be absolutely crazy. I am a big fan of GPS, and I have been
messing with GPS in aviation for at least 10 years. I will be one of the
first to vote with my feet when it comes to GPS.

What I don't understand about GPS is why some of them have synthetic HSIs.
One of the new features in the GNS-480 vs. the CNX-80, for example, was the
addition of a "NAV" page, which shows a picture of an quasi-HSI (quasi
because the numbers are showing track, not heading). What's the point?
You've already got a far, superior representation in the moving map. The
position of the aircraft icon relative to the purple line shows your course
deviation, and the *orientation* of the icon shows whether you're getting
better or worse. Displacement AND trend in one picture.

What's the point?
You've already got a far, superior representation in the moving map.

The moving map is not as precise a navigation aid. At least I find
that, when I use the synthetic CDI my track is much more precise then
when I use the moving map.

Jose
--
The monkey turns the crank and thinks he's making the music.
for Email, make the obvious change in the address.

Roy Smith wrote:

What I don't understand about GPS is why some of them have synthetic HSIs.
One of the new features in the GNS-480 vs. the CNX-80, for example, was the
addition of a "NAV" page, which shows a picture of an quasi-HSI (quasi
because the numbers are showing track, not heading). What's the point?
You've already got a far, superior representation in the moving map. The
position of the aircraft icon relative to the purple line shows your course
deviation, and the *orientation* of the icon shows whether you're getting
better or worse. Displacement AND trend in one picture.

I find the NAV page on the 480 gives me more trend information in a quick glance
than the map presentation. I use it during approaches. Enroute I use the map.

DGB

On 9/5/2006 8:51 PM, Roy Smith wrote the following:
Displacement AND trend in one picture.

Yes, if you use the map at a magnification to match the ten mile or two mile
width of the CDI. Do you actually do this?

Mitty wrote:
On 9/5/2006 8:51 PM, Roy Smith wrote the following:
Displacement AND trend in one picture.

Yes, if you use the map at a magnification to match the ten mile or two mile
width of the CDI. Do you actually do this?

I find that the autozoom mode achieves exactly what is needed while
flying an approach (or just "approaching" an airport), i.e. the visual
presentation of the course line and airplane icon on the map increases
in precision as you get closer...
--
Cheers,
John Clonts
Temple, Texas
N7NZ