to HSI or not to HSI

On Sun, 14 Nov 2004 21:09:21 -0500, "Richard Kaplan"
wrote:

wrote in message
.. .

As far as radios are concerned, if you have the OBS ring set to the
single localizer course, and you are west of course, it will indicate
west

I say again.... when things are bouncing around in the airplane and you need
a quick answer, which way do you turn when the needle is deflected?


Easy as 1-2--3

You (1) look at the OBS, (2) select a heading on the needle side
that provides the intercept angle you desire, and (3) fly that
heading. You willl intercept the course on that angle.




For 99% of pilots, it is MUCH easier to turn in the direction of the needle
than to consider which geometric side of the course will result in what sort
of deflection. It is MUCH easier and safer if interpretation of the needle
is simplified in this format.


Only because of the law of primacy. It is not MUCH easier, in fact it
is more complex because of the mental processing required, and it is
certainly not safer. I have seen too many pilots reverse course and
fly away from their desired approach course because they kept turning
right or left when the needle didn't start to center.




"Forward" vs. "Reverse" sensing are indeed simply paradigms based upon the
pilot's perspective of the world. For most pilots, the "Forward" sensing
paradigm is much easier to interpret than your alternative (though
acceptable) geometric paradigm.

How would you know this? You have obviously never used the method, so
you have no basis to make this statement.



I agree that the "Reverse" sensing paradigm
is a bit harder than your geometric paradigm, but that accounts for a small
minority of time for most pilots compared with time under the "Forward"
paradigm.

--------------------
Richard Kaplan

www.flyimc.com

wrote:

Start by explaining that the ONLY information provided by a VOR head
is the position of the aircraft with respect to two lines.

Actually, it gives you the position with respect to four lines, as the
TO/FROM flag allows you to bisect the course line and narrow your
position down to one of four quandrants. This is explained particularly
well in Peter Dogan's book.


There is NO directional information provided, and without some other
instrument to provide directional information, it is useless as a
navigation tool.

Well, not exactly. It provides no information as to the heading of the
aircraft, but it provides a lot of information as to what direction to fly.

Matt

On Mon, 15 Nov 2004 06:45:28 -0500, Matt Whiting
wrote:

wrote:

Start by explaining that the ONLY information provided by a VOR head
is the position of the aircraft with respect to two lines.

Actually, it gives you the position with respect to four lines, as the
TO/FROM flag allows you to bisect the course line and narrow your
position down to one of four quandrants. This is explained particularly
well in Peter Dogan's book.


If you visualize the lines stopping at the VOR and another continuing
out the other side. I prefer to visualize that as a single line,
therefore I visualize only two lines.


There is NO directional information provided, and without some other
instrument to provide directional information, it is useless as a
navigation tool.

Well, not exactly. It provides no information as to the heading of the
aircraft, but it provides a lot of information as to what direction to fly.

Matt

As I said, without the sun, the stars, or an instrument to use to
turn to that direction, it is useless.

Am I missing something in this thread? With an HSI if you set the front course
bearing on the OBS, you fly inbound on a back course approach into the needle
just as you do with the front course.

Richard Kaplan wrote:

wrote in message
...

As far as radios are concerned, if you have the OBS ring set to the
single localizer course, and you are west of course, it will indicate
west

I say again.... when things are bouncing around in the airplane and you need
a quick answer, which way do you turn when the needle is deflected?

For 99% of pilots, it is MUCH easier to turn in the direction of the needle
than to consider which geometric side of the course will result in what sort
of deflection. It is MUCH easier and safer if interpretation of the needle
is simplified in this format.

"Forward" vs. "Reverse" sensing are indeed simply paradigms based upon the
pilot's perspective of the world. For most pilots, the "Forward" sensing
paradigm is much easier to interpret than your alternative (though
acceptable) geometric paradigm. I agree that the "Reverse" sensing paradigm
is a bit harder than your geometric paradigm, but that accounts for a small
minority of time for most pilots compared with time under the "Forward"
paradigm.

--------------------
Richard Kaplan

www.flyimc.com

On Mon, 15 Nov 2004 06:32:32 -0800, wrote:

Am I missing something in this thread? With an HSI if you set the front course
bearing on the OBS, you fly inbound on a back course approach into the needle
just as you do with the front course.



Yep.

Exactly what you do with a DG/OBS, if you create a mental HSI by
superimposing the DG onto the OBS, or vice versa.

An HSI does not sense anything any differently. It combines two
instruments for ease of interpretation. The same thing can be done
mentally, if you want to save yourself $8000 or so.

If you set the OBS to the inbound course on a back course, and fly
headings that are on the CDI side of the OBS ring, you are doing what
the HSI "tells" you to do.



Richard Kaplan wrote:

wrote in message
...

As far as radios are concerned, if you have the OBS ring set to the
single localizer course, and you are west of course, it will indicate
west

I say again.... when things are bouncing around in the airplane and you need
a quick answer, which way do you turn when the needle is deflected?

For 99% of pilots, it is MUCH easier to turn in the direction of the needle
than to consider which geometric side of the course will result in what sort
of deflection. It is MUCH easier and safer if interpretation of the needle
is simplified in this format.

"Forward" vs. "Reverse" sensing are indeed simply paradigms based upon the
pilot's perspective of the world. For most pilots, the "Forward" sensing
paradigm is much easier to interpret than your alternative (though
acceptable) geometric paradigm. I agree that the "Reverse" sensing paradigm
is a bit harder than your geometric paradigm, but that accounts for a small
minority of time for most pilots compared with time under the "Forward"
paradigm.

--------------------
Richard Kaplan

www.flyimc.com

wrote:

On Mon, 15 Nov 2004 06:32:32 -0800, wrote:

Am I missing something in this thread? With an HSI if you set the front course
bearing on the OBS, you fly inbound on a back course approach into the needle
just as you do with the front course.

Yep.

Exactly what you do with a DG/OBS, if you create a mental HSI by
superimposing the DG onto the OBS, or vice versa.


I don't think my brain could handle that one. I did a lot of instrument instructing
many years ago, before HSIs appeared in light aircraft. I thought then, and think
now, of flying away from the CDI needle when flying inbound on a back course.

"Richard Hertz" no one@no one.com wrote
Here disagree - the current use appears to imply a "design flaw" but that
is only because of imporper use and instruction of the instrument. It does
not "point" to the course, rather it shows what sector of the localizer
course you are on. (shaded or unshaded.)

This is of course correct - provided you can get the student to do
mental math on the approach. Of course to someone brought up on the
ADF, that's not a big deal - if you fly ADF approaches, every approach
requires mental math all the time.

However, in today's instructional environment, the ADF is introduced
late (as an advanced technique) or not introduced at all (since it is
no longer required). Further, in the real world of IFR flying, the
ADF is no longer particularly relevant to most pilots.

It is a back course - meaning you are coming from the other way. You know
this. Clearly the instruction should be corrected - it is a lot cheaper
than everyone buying HSIs.

It may not be cheaper than installing a switch. Instruction also
costs money, if nothing else than in aircraft operation time. In the
higher end aircraft, it may not be cheaper than buying HSI's.

but the addition of a cheap,
simple, and reliable part to the CDI (or replacement with an HSI)
eliminates the potential for error - and is thus clearly an advantage.

And what is thins part?

The switch.

I contest that ensuring the blue and yellow colors on the instrument and
proper training would avert the confusion.

I'm not convinced that blue and yellow colors on the instrument would
be cheaper than the switch. They are certainly not common on modern
CDI's. And the proper training you advocate involves being able to do
mental math, which in my experience most pilots can't do. You may not
realize this, but the elementary education system has changed. Have
you ever seen what happens at a store these days when the power goes
down and the cash registers don't work? Everything grinds to a halt;
most of the cashiers can't make change without the register computing
it.

Michael

It seems hard only because you learned a different method, and old
ideas and habits are hard to replace with new ones.

It's a real simple concept, however, simpler really than "reverse
sensing" by a a lot. Anyone can learn it, and it takes the guesswork
out of the equation.





On Mon, 15 Nov 2004 07:32:44 -0800, wrote:



wrote:

On Mon, 15 Nov 2004 06:32:32 -0800, wrote:

Am I missing something in this thread? With an HSI if you set the front course
bearing on the OBS, you fly inbound on a back course approach into the needle
just as you do with the front course.

Yep.

Exactly what you do with a DG/OBS, if you create a mental HSI by
superimposing the DG onto the OBS, or vice versa.


I don't think my brain could handle that one. I did a lot of instrument instructing
many years ago, before HSIs appeared in light aircraft. I thought then, and think
now, of flying away from the CDI needle when flying inbound on a back course.

"Michael" wrote in message
om...
"Richard Hertz" no one@no one.com wrote
Here disagree - the current use appears to imply a "design flaw" but
that
is only because of imporper use and instruction of the instrument. It
does
not "point" to the course, rather it shows what sector of the localizer
course you are on. (shaded or unshaded.)

This is of course correct - provided you can get the student to do
mental math on the approach. Of course to someone brought up on the
ADF, that's not a big deal - if you fly ADF approaches, every approach
requires mental math all the time.

What mental math? You look at the needle, determine what sector it is in,
then look at the chart and matchi it up. There is no math - you just match
a pattern of shaded or unshaded. I don't understand your objection about it
being difficult.



However, in today's instructional environment, the ADF is introduced
late (as an advanced technique) or not introduced at all (since it is
no longer required). Further, in the real world of IFR flying, the
ADF is no longer particularly relevant to most pilots.

I don't know if I would go that far. For those that use them it is a
wonderful tool. For those that do not it is useless.


It is a back course - meaning you are coming from the other way. You
know
this. Clearly the instruction should be corrected - it is a lot cheaper
than everyone buying HSIs.

It may not be cheaper than installing a switch. Instruction also
costs money, if nothing else than in aircraft operation time. In the
higher end aircraft, it may not be cheaper than buying HSI's.

Agreed, but my point was that if the training had been correct the first
time around it would all be avoided.


but the addition of a cheap,
simple, and reliable part to the CDI (or replacement with an HSI)
eliminates the potential for error - and is thus clearly an advantage.

And what is thins part?

The switch.

And you think that people would remember to flip the switch? It is
essentially the same issue as remembering you are on a BC. If you can
remember that you don't need the switch. It is the same problem, but now
you have added a component to the avioinics...

As you pointed out earier I seem to have started a religious war and I am
sorry for it. I have not been on this group long enough to have seen this
one before. My apologies.


I contest that ensuring the blue and yellow colors on the instrument and
proper training would avert the confusion.

I'm not convinced that blue and yellow colors on the instrument would
be cheaper than the switch. They are certainly not common on modern
CDI's. And the proper training you advocate involves being able to do
mental math, which in my experience most pilots can't do.

A simple memory aid will also work. But again, I see no mental math to do.
Nothing can be simpler.

You may not
realize this, but the elementary education system has changed. Have
you ever seen what happens at a store these days when the power goes
down and the cash registers don't work? Everything grinds to a halt;
most of the cashiers can't make change without the register computing
it.

I do, and I lament it terribly. I own many rental properties and pay taxes
for many school districts and I am certainly not getting my "money's worth"
from our local governments. I tutored some students recently and was
appalled at the curriculum and the text books.




Michael

wrote:

On Mon, 15 Nov 2004 06:32:32 -0800, wrote:


Am I missing something in this thread? With an HSI if you set the front course
bearing on the OBS, you fly inbound on a back course approach into the needle
just as you do with the front course.




Yep.

Exactly what you do with a DG/OBS, if you create a mental HSI by
superimposing the DG onto the OBS, or vice versa.

An HSI does not sense anything any differently. It combines two
instruments for ease of interpretation. The same thing can be done
mentally, if you want to save yourself $8000 or so.

If you set the OBS to the inbound course on a back course, and fly
headings that are on the CDI side of the OBS ring, you are doing what
the HSI "tells" you to do.

True, but the HSI makes it much easier.


Matt