Violating Airspace with GPS

[John Bell]

It appears that a lot of pilots are violating airspace even with GPS on
board.

I would like to hear some feedback as to how pilots are violating airspace
with GPS. I address this in my online book, www.cockpitgps.com. I have my
hypothesis, but I would like to hear your experience or scenarios that you
have heard involving this issue.

Also of interest is how you might be using GPS to successfully avoid
airspace violations.

Other hypothesis are also welcome.

Thanks,

John Bell
www.cockpitgps.com

Here is my hypothesis:

I have already mentioned in my discussion of database currency that you
should set up a routing around any airspace and check it with a current
chart before flight. Even with a current database, it is possible for the
GPS to get you into trouble with airspaces.
Aviation receivers can be setup to display airspace boundaries and to give
warnings before entering certain airspace classifications such as category B
airspace. These warnings can be a great benefit or a nuisance depending on
the type of flying that you are doing. Thus, most receivers allow you to
turn them on or off. Additionally, which boundaries will display and at what
point of zooming out they will disappear can be set. The ability to make
these settings is a good feature and I would not want to see this changed.
However, it is possible to have the GPS not display or not warn of an
impending airspace violation if you have the GPS set up incorrectly for the
mission.
Even if the airspace boundary is displayed, it is often difficult to decide
what boundary a given line applies to. On the Garmin aviation receivers it
is possible to cursor over the point to get a description. On a handheld GPS
just press the rocker pad up, down, left, or right to start moving the
cursor. On the GPS 400 and 500 series, press in on the knob and then start
moving the cursor. Move the cursor to highlight the line and press the ENTER
button to get information on the airspace. This is a great feature at the
planning stage and is occasionally useful in flight. When you have
preplanned the route and have a route line, the context of the border is
obvious. However, I think that it is possible to confuse borders and violate
airspace without first creating a route using a chart before flight.

[Ron Natalie]

"John Bell" > wrote in message om...

> Other hypothesis are also welcome.
>
Class B airspace, not category B.

Your simplified definition of GPS, while one of the common ones often espoused
has no basis in reality. This is not how GPS works.

Your information on RAIM is wrong. What is unique about the RAIM used in IFR
approved GPS's is not that it determines when the satellite geometry is giving you
an error NOW, but computes if it will fail while during the expected duration of flying
an instrument approach.

[Ben Jackson]

In article >,
John Bell > wrote:
>
>I would like to hear some feedback as to how pilots are violating airspace
>with GPS.

Someone here just posted about busting SEA's class B (partly) due to
being zoomed in too far to get the big picture.

I flew straight into a class D instead of skirting it because I hadn't
been using the GPS map for anything up to that point and someone else
had switched it (rental plane) from track-up to north-up. I would have
missed it (my pilotage was fine) but the map put it just north of me
which I read as 'right in front of me' so I turned while I tried to
figure out how I could possibly be where it said I was...

--
Ben Jackson
>
http://www.ben.com/

[John Bell]

I will see where I wrote category B instead of class B. It is simply a
typo. Thanks for catching that.

I am certainly up for a better explanation of how GPS works. Indeed my
information comes from the common espousals.

I understand the concept of RAIM prediction, that the GPS can predict the
unavailability of RAIM. However, I was not aware that RAIM had the ability
to predict as oppose to detect positioning errors.

I would appreciate further information on either basic GPS or RAIM.

John Bell


"Ron Natalie" > wrote in message
m...
>
> "John Bell" > wrote in message
om...
>
> > Other hypothesis are also welcome.
> >
> Class B airspace, not category B.
>
> Your simplified definition of GPS, while one of the common ones often
espoused
> has no basis in reality. This is not how GPS works.
>
> Your information on RAIM is wrong. What is unique about the RAIM used in
IFR
> approved GPS's is not that it determines when the satellite geometry is
giving you
> an error NOW, but computes if it will fail while during the expected
duration of flying
> an instrument approach.
>
>
>

[Roger Tracy]

I use a Garmin 300 IFR GPS .. and a Garmin 196 handheld. I keep the IFR
database
current and update the handheld about once a year. I've had no trouble
working
around and under the Class B shelves using them. When compared to prominent
landmarks (roads, etc) that help identify the boundaries, they seem to be
highly
accurate. Some Class B's have VFR waypoints shown on the TAC and those
help. An important thing is to keep the zoom set correctly so you can
identify
just where you're at in relation to the different B floors. If you're zoomed
in
too close .. you may think you're under the wrong one. I like to zoom so I
can
see the B space to it's outermost ring.


"John Bell" > wrote in message
om...
> It appears that a lot of pilots are violating airspace even with GPS on
> board.
>
> I would like to hear some feedback as to how pilots are violating airspace
> with GPS. I address this in my online book, www.cockpitgps.com. I have
my
> hypothesis, but I would like to hear your experience or scenarios that you
> have heard involving this issue.
>
> Also of interest is how you might be using GPS to successfully avoid
> airspace violations.
>
> Other hypothesis are also welcome.
>
> Thanks,
>
> John Bell
> www.cockpitgps.com
>
> Here is my hypothesis:
>
> I have already mentioned in my discussion of database currency that you
> should set up a routing around any airspace and check it with a current
> chart before flight. Even with a current database, it is possible for the
> GPS to get you into trouble with airspaces.
> Aviation receivers can be setup to display airspace boundaries and to give
> warnings before entering certain airspace classifications such as category
B
> airspace. These warnings can be a great benefit or a nuisance depending on
> the type of flying that you are doing. Thus, most receivers allow you to
> turn them on or off. Additionally, which boundaries will display and at wh
at
> point of zooming out they will disappear can be set. The ability to make
> these settings is a good feature and I would not want to see this changed.
> However, it is possible to have the GPS not display or not warn of an
> impending airspace violation if you have the GPS set up incorrectly for
the
> mission.
> Even if the airspace boundary is displayed, it is often difficult to
decide
> what boundary a given line applies to. On the Garmin aviation receivers it
> is possible to cursor over the point to get a description. On a handheld
GPS
> just press the rocker pad up, down, left, or right to start moving the
> cursor. On the GPS 400 and 500 series, press in on the knob and then start
> moving the cursor. Move the cursor to highlight the line and press the
ENTER
> button to get information on the airspace. This is a great feature at the
> planning stage and is occasionally useful in flight. When you have
> preplanned the route and have a route line, the context of the border is
> obvious. However, I think that it is possible to confuse borders and
violate
> airspace without first creating a route using a chart before flight.
>
>
>
>
>

[Larry Dighera]

On Thu, 30 Oct 2003 19:08:37 GMT, "John Bell"
> wrote in Message-Id:
>:

>Other hypothesis are also welcome.

It is imperative that a pilot maintain situational awareness at all
times. The responsibility is his alone. GPS is a valuable aid. The
pilot who relies upon GPS exclusively to provide situational awareness
soon learns that won't work; it only provides positional information
(and speed). Situational awareness encompasses a great deal more....

[Larry Dighera]

On Thu, 30 Oct 2003 20:38:40 GMT, "John Bell"
> wrote in Message-Id:
>:

>I am certainly up for a better explanation of how GPS works.

Are you aware of this mailing list?

GPS for Aviation:

http://www.lsoft.com/scripts/wl.exe?SL1=GPS-AERO&H=LISTSERV.UNB.CA

There are very knowledgable folks willing to answer all your questions
there.

[Robert Moore]

Larry Dighera > wrote

> There are very knowledgable folks willing to answer all your
> questions there.

:-) :-) Since John has written texts on GPS Navigation, I suspect
that he was pulling someone's leg.

http://www.smallboatgps.com/ http://www.cockpitgps.com/


Hi John, how's things going? Remember meeting at SnF?

Bob Moore

[C J Campbell]

Many GPS and MFD displays are too crummy to be of any real use in avoiding
airspace. The Bendix-King displays are among the worst. Even the color MFD
display is only half VGA quality and uses magenta lines for everything from
depicting airspace to the flight planned route. It is very easy to mistake
an airspace line for something else with this unit. Also, most displays
cannot draw curved lines very well, so when you zoom into a lot of class B
you discover that instead of a circle it is a complex polygon.

I think the biggest troublemaker is the 'nearest' function on most GPS
units. The pilot punches in 'nearest' thinking that is the airport he wants
to go to when in fact the GPS selects some other waypoint. The pilot is busy
and does not do a good job of checking.

Another troublemaker is the flight plan route function. The pilot either
leaves out an intermediate waypoint or enters an incorrect one with the same
or a similar identifier, then follows the courseline right into airspace
where he does not belong. Another problem is not clearing out an old flight
plan before entering a new one. This is especially common on GPS units like
the King KLN 94. A pilot will select direct to an airport without clearing
the flight plan entered in a previous flight. When he wants to fly an
approach, he presses PROC, selects the approach, and appends it to the old
flight plan. Then he does not activate the approach and the next thing you
know he has wandered off 180 degrees from where he should be.

Getting confused on whether the CDI is displaying NAV or GPS information is
another source of trouble.

Pilots also blunder into airspace because they are fooling around with the
GPS instead of paying attention to what they are doing. They are
particularly likely to do this if the GPS goes off line for some reason. It
is an especially serious problem with handheld GPS.

Then there are outright database errors. Jeppesen mis-plotted some class B
airspace a few months ago and someone posted just recently that Jeppesen
missed that the Savannah VOR had been moved.

Of course, most airspace violations are of things like the Washington ADIZ
and TFRs, which are not in most GPS databases, depicted on any charts, or
otherwise easily accessible. In fact, even the FAA is unable to plot many of
these TFRs accurately. Many TFRs give as their center both a lat/long and a
radial/DME, which may be a mile or more apart -- this is a big deal when you
consider that a TFR may be only three miles in radius. Additionally, TFRs
may change size, shape and duration with little or no notice, long after the
pilot has taken off. The best navigation techniques in the world will not
help you with that.

The fundamental problem that I see the most is that pilots just get behind
the airplane. Instead of setting up the GPS in advance, they wait until the
last minute, attempting to do things like set up an approach as they enter
the final approach course. It gets pretty wild watching students do that.
Then they panic, wander off course, and get into airspace.

I do not claim to have made all these mistakes myself, of course.

[Kyle Boatright]

"John Bell" > wrote in message
om...
> It appears that a lot of pilots are violating airspace even with GPS on
> board.
>
> I would like to hear some feedback as to how pilots are violating airspace
> with GPS. I address this in my online book, www.cockpitgps.com. I have
my
> hypothesis, but I would like to hear your experience or scenarios that you
> have heard involving this issue.
>
> Also of interest is how you might be using GPS to successfully avoid
> airspace violations.
>
> Other hypothesis are also welcome.
>
> Thanks,
>
> John Bell

I've had a couple of *near misses* with airspace. The first time, my GPS
database was outdated, and I realized fairly late that the paper map didn't
show the same thing the GPS map showed. The controlled airspace had
expanded from a 5(?) radius around Montgomery, Ala to 10 (?) miles, and my
GPS had the old data. I looked and looked at the map thinking "that's a
bigger circle than what shows on the magic box"... Then I put a scale on the
map and realized that my eyeball was correct. I was close enough that
evasive action was necessary.

Another time, I was climbing around a series of clouds in a scattered/broken
layer, reached "on-top" and realized that I was surprisingly near Atlanta's
Class "C". Again, I had to make a course correction to avoid the airspace.
Obviously, I focused too hard to pick the best route around the clouds, and
didn't focus enough on my actual position relative to the airspace...

KB

[Colin Southern]

Interesting timing ...

At present I'm trying (without much success) to investigate an apparent
anomoly where my GPSMAP 295 (with latest database and firmware) is
steadfastly refusing to acknowledge some of our controlled airspace - and is
yet quite happy to display adjacent controlled airspace.

As it stands at the moment with my GPS I could quite happily fly into the
middle of the Nelson TMA and not have the GPS give any indication of being
in any kind of controlled airspace.

See my post from yesterday if anyone is able to help us resolve this (no
replies to date)

Cheers,

Colin


"John Bell" > wrote in message
om...
> It appears that a lot of pilots are violating airspace even with GPS on
> board.
>
> I would like to hear some feedback as to how pilots are violating airspace
> with GPS. I address this in my online book, www.cockpitgps.com. I have
my
> hypothesis, but I would like to hear your experience or scenarios that you
> have heard involving this issue.
>
> Also of interest is how you might be using GPS to successfully avoid
> airspace violations.
>
> Other hypothesis are also welcome.
>
> Thanks,
>
> John Bell
> www.cockpitgps.com
>
> Here is my hypothesis:
>
> I have already mentioned in my discussion of database currency that you
> should set up a routing around any airspace and check it with a current
> chart before flight. Even with a current database, it is possible for the
> GPS to get you into trouble with airspaces.
> Aviation receivers can be setup to display airspace boundaries and to give
> warnings before entering certain airspace classifications such as category
B
> airspace. These warnings can be a great benefit or a nuisance depending on
> the type of flying that you are doing. Thus, most receivers allow you to
> turn them on or off. Additionally, which boundaries will display and at
what
> point of zooming out they will disappear can be set. The ability to make
> these settings is a good feature and I would not want to see this changed.
> However, it is possible to have the GPS not display or not warn of an
> impending airspace violation if you have the GPS set up incorrectly for
the
> mission.
> Even if the airspace boundary is displayed, it is often difficult to
decide
> what boundary a given line applies to. On the Garmin aviation receivers it
> is possible to cursor over the point to get a description. On a handheld
GPS
> just press the rocker pad up, down, left, or right to start moving the
> cursor. On the GPS 400 and 500 series, press in on the knob and then start
> moving the cursor. Move the cursor to highlight the line and press the
ENTER
> button to get information on the airspace. This is a great feature at the
> planning stage and is occasionally useful in flight. When you have
> preplanned the route and have a route line, the context of the border is
> obvious. However, I think that it is possible to confuse borders and
violate
> airspace without first creating a route using a chart before flight.
>
>
>
>
>

[BTIZ]

Bingo...

"C J Campbell"
> Pilots also blunder into airspace because they are fooling around with the
> GPS instead of paying attention to what they are doing.

[John Bell]

Robert,

I do indeed remember meeting you in Lakeland. Whenever I see one of your
posts, it is like picking up a paper and seeing a byline from a reporter
that I respect.

Actually, my response to Ron Natalie was a little more than tongue in cheek.
It was somewhat of a combination of defensiveness and worry that I might be
spreading bad information. Ron's statement that my explanation of how GPS
works: "while one of the common ones often espoused
has no basis in reality. This is not how GPS works" has me curious.

Unfortunately, Ron's statement unfortunately gives me little to correct my
understanding if it is indeed wrong. Luckily, even if my explanation of how
GPS works is totally incorrect, it should not have serious consequences as
far as usage is concerned.


John

"Robert Moore" > wrote in message
. 7...
> Larry Dighera > wrote
>
> > There are very knowledgable folks willing to answer all your
> > questions there.
>
> :-) :-) Since John has written texts on GPS Navigation, I suspect
> that he was pulling someone's leg.
>
> http://www.smallboatgps.com/ http://www.cockpitgps.com/
>
>
> Hi John, how's things going? Remember meeting at SnF?
>
> Bob Moore
>

[John Bell]

CJ,

Thanks very much for the response. Your perspective is very illuminating
and confirms many of my suspicions and observations.

I often fly over near Washington, D.C. I can't tell you how many times that
I have heard the authorities trying to raise an aircraft that has violated
the Washington ADIZ on 121.5. The same aircraft that is violating the
airspace are usually not monitoring 121.5. Usually, it is a futile
broadcast in the blind. In fact I have never heard a response from an
errant aircraft.

Thanks everybody else for your responses also.

--John Bell
www.cockpitgps.com

[Kobra]

The biggest problem appears to be when the pilot has the Zoom level too
tight and they can't see all the rings and miss read one level for another.

Kobra

"John Bell" > wrote in message
om...
> It appears that a lot of pilots are violating airspace even with GPS on
> board.
>
> I would like to hear some feedback as to how pilots are violating airspace
> with GPS. I address this in my online book, www.cockpitgps.com. I have
my
> hypothesis, but I would like to hear your experience or scenarios that you
> have heard involving this issue.
>
> Also of interest is how you might be using GPS to successfully avoid
> airspace violations.
>
> Other hypothesis are also welcome.
>
> Thanks,
>
> John Bell
> www.cockpitgps.com
>
> Here is my hypothesis:
>
> I have already mentioned in my discussion of database currency that you
> should set up a routing around any airspace and check it with a current
> chart before flight. Even with a current database, it is possible for the
> GPS to get you into trouble with airspaces.
> Aviation receivers can be setup to display airspace boundaries and to give
> warnings before entering certain airspace classifications such as category
B
> airspace. These warnings can be a great benefit or a nuisance depending on
> the type of flying that you are doing. Thus, most receivers allow you to
> turn them on or off. Additionally, which boundaries will display and at
what
> point of zooming out they will disappear can be set. The ability to make
> these settings is a good feature and I would not want to see this changed.
> However, it is possible to have the GPS not display or not warn of an
> impending airspace violation if you have the GPS set up incorrectly for
the
> mission.
> Even if the airspace boundary is displayed, it is often difficult to
decide
> what boundary a given line applies to. On the Garmin aviation receivers it
> is possible to cursor over the point to get a description. On a handheld
GPS
> just press the rocker pad up, down, left, or right to start moving the
> cursor. On the GPS 400 and 500 series, press in on the knob and then start
> moving the cursor. Move the cursor to highlight the line and press the
ENTER
> button to get information on the airspace. This is a great feature at the
> planning stage and is occasionally useful in flight. When you have
> preplanned the route and have a route line, the context of the border is
> obvious. However, I think that it is possible to confuse borders and
violate
> airspace without first creating a route using a chart before flight.
>
>
>
>
>

[G.R. Patterson III]

John Bell wrote:
>
> It appears that a lot of pilots are violating airspace even with GPS on
> board.

Actually, from what I've read, *more* violations occur with GPS on board than
without. The reason is that pilots with GPS tend to cut pretty close to the
limits because the *think* they know exactly where those airspace limits are.
Pilots without GPS receivers tend to give protected airspace a little more
leeway because they aren't exactly sure where they are.

George Patterson
You can dress a hog in a tuxedo, but he still wants to roll in the mud.

[Cub Driver]

> In fact I have never heard a response from an
>errant aircraft.

The response, had it been audible, probably would have been along the
lines of: "I may be errant, but I'm not stupid!"

all the best -- Dan Ford
email:

see the Warbird's Forum at www.warbirdforum.com
and the Piper Cub Forum at www.pipercubforum.com

[Gene Seibel]

Violation of airspace comes from lack of preflight planning. If you
wait until you are in the air near airspace to figure out what you are
doing, you are in big trouble, with or without GPS. You can see from
dozens of past threads in this group about no longer carrying charts,
etc, that many pilots think GPS is magic and will solve all their
problems. Not true at all. Technology does not take the place of
common sense and diligence. With blind dependence on technology, you
can get into deeper doo-doo a lot faster than without it. A GPS is
great for telling you where you are, but you've got to know where you
want to be first. I seldom use my moving map. I use GPS to verify that
I am on my pre-planned course and I don't violate airspace.
--
Gene Seibel
Hangar 131 - http://pad39a.com/gene/plane.html
Because I fly, I envy no one.


> I would like to hear some feedback as to how pilots are violating airspace
> with GPS. I address this in my online book, www.cockpitgps.com. I have my
> hypothesis, but I would like to hear your experience or scenarios that you
> have heard involving this issue.
>
> Also of interest is how you might be using GPS to successfully avoid
> airspace violations.

[noah]

IMHO: GPS stinks (today) for airspace mapping/boundaries.

About a year ago I was flying a 172 with a B&W Garmin (Panel mounted -
I'm not sure the model) and the database was somehow incorrect -
placing Santa Rosa STS about 8-10 miles North of it's actual position.
There was a VOR on field - why use GPS there?

A month ago, I was flying a club 172 with a panel mounted Garmin 430
(I think IFR certified too). As I skirted San Jose's (SJC) class C,
the 430 showed me about 1mi *inside* the outer shelf. I stayed low
around 2000'-2500' (I forget at the moment, but was being a 'good
citizen') and as I saw the mountains ahead (flying South towards
Monterey) asked Norcal Appch/Dep if I was clear of SJC's C. They were
nice, friendly, and said something like: "Yeah - you were clear miles
ago". Looking out the window, I would roughly estimate my distance to
SJC to be in the 10-15mi range, but I was waiting for the magical
gizmo to *show* me that I was clear of the shelf.

Moral of the story: I purchased a simple handheld Magellan that I can
use as (a) a backup, and (b) a simple course/groundspeed calculator.
I'd rather not have the distractions of potentially inaccurate
colorful inside maps when my eyeballs should be outside the plane at
as much as possible.

Just my 2c.
Noah



> > It appears that a lot of pilots are violating airspace even with GPS on
> > board.
>
> Actually, from what I've read, *more* violations occur with GPS on board than
> without. The reason is that pilots with GPS tend to cut pretty close to the
> limits because the *think* they know exactly where those airspace limits are.
> Pilots without GPS receivers tend to give protected airspace a little more
> leeway because they aren't exactly sure where they are.
>
> George Patterson
> You can dress a hog in a tuxedo, but he still wants to roll in the mud.

[Icebound]

Gene Seibel wrote:
> ...snip... A GPS is
> great for telling you where you are, but you've got to know where you
> want to be first. I seldom use my moving map.

Completely agree except for one point...

A GPS is excellent at *knowing* where you are, but very few of them (if
any) can transfer that information to you in a suitably efficient way.
So I disagree that they are "...great for *telling you* where you
are..." :-) Trying to interpret that tiny moving map is where the
distractions occur and the potential for error...

Concentrating on CTS, Bearing to next waypoint, and XTE for a
well-planned (and correctly entered) route, is so much easier and more
informative.

Perhaps the GPS is making us forget that it is so much more important to
know where to go next, than it is to confirm where you are now.

[Mike Beede]

In article >, Ron Natalie > wrote:

> Your information on RAIM is wrong. What is unique about the RAIM used in IFR
> approved GPS's is not that it determines when the satellite geometry is giving you
> an error NOW, but computes if it will fail while during the expected duration of flying
> an instrument approach.

That's RAIM *prediction*. RAIM is very capable of failing during an approach if
you don't check the prediction ahead of time, at least on our Garmin 430.

I don't know what John's information on RAIM is, since it will be two or three
hours before his books is downloaded.

Regards,

Mike

[Gene Seibel]

I guess I still wasn't clear on what I was trying to say. A GPS is
great for knowing where you are on a pre-planned course. A GPS moving
map isn't good for much of anything.
--
Gene Seibel
Hangar 131 - http://pad39a.com/gene/plane.html
Because I fly, I envy no one.




> Gene Seibel wrote:
> > ...snip... A GPS is
> > great for telling you where you are, but you've got to know where you
> > want to be first. I seldom use my moving map.
>
> Completely agree except for one point...
>
> A GPS is excellent at *knowing* where you are, but very few of them (if
> any) can transfer that information to you in a suitably efficient way.
> So I disagree that they are "...great for *telling you* where you
> are..." :-) Trying to interpret that tiny moving map is where the
> distractions occur and the potential for error...
>
> Concentrating on CTS, Bearing to next waypoint, and XTE for a
> well-planned (and correctly entered) route, is so much easier and more
> informative.
>
> Perhaps the GPS is making us forget that it is so much more important to
> know where to go next, than it is to confirm where you are now.

[Newps]

Gene Seibel wrote:

> I guess I still wasn't clear on what I was trying to say. A GPS is
> great for knowing where you are on a pre-planned course. A GPS moving
> map isn't good for much of anything.

Huh? Wouldn't be without mine. A GPS without a moving map is useless.

[John Bell]

"Gene Seibel" > I guess I still wasn't clear on what I was trying to say. A
GPS is
> great for knowing where you are on a pre-planned course. A GPS moving
> map isn't good for much of anything.

"Icebound"
> > Concentrating on CTS, Bearing to next waypoint, and XTE for a
> > well-planned (and correctly entered) route, is so much easier and more
> > informative.

I am somewhat in disagreement on the usefulness of the map: I actually
consider the GPS map to be a very useful feature. I even consider this to
be the case in low resolution models such as the GPS III Pilot. However, I
feel that the map display is insufficient without the assistance of changing
the data fields displayed on the map page to something more useful. The map
is good at adding context to the data fields and the data fuilds are good
for adding precision to the map. I like TURN (TRACK-BEARING), OFF COURSE
(XTE), DISTANCE, and WPT (I like a textual indication of the waypoint--
accurately navigating to the wrong place is pointless).

I very strongly agree that a properly preplanned course with reference to
the proper charts is mandatory.


John Bell
www.cockpitgps.com

[Robert Moore]

(Gene Seibel) wrote

> A GPS moving map isn't good for much of anything.

BULL****!!! Strong statement to follow.....

Bob Moore
ATP CFII

[Thomas Borchert]

Gene,

> I guess I still wasn't clear on what I was trying to say. A GPS is
> great for knowing where you are on a pre-planned course. A GPS moving
> map isn't good for much of anything.
>

Well, I couldn't agree less. GPS moving maps are a WONDERFUL tool for
situational awareness. In fact, beyond the AI, it doesn't get much
better. If you think wasting your time interpreting arcane needles is
better, it may be time to tune down the machismo ;-)

--
Thomas Borchert (EDDH)

[[email protected]]

On Mon, 03 Nov 2003 17:01:01 +0100, Thomas Borchert
> wrote:

>Well, I couldn't agree less. GPS moving maps are a WONDERFUL tool for
>situational awareness.


Did you mean to say positional awareness? Positional awareness is
only a small part of situational awareness.

[Thomas Borchert]

> Did you mean to say positional awareness? Positional awareness is
> only a small part of situational awareness.
>

Well, if what you say is correct, I guess I was correct to say
"situational awareness". IMHO it gives you more than positional
awareness.

--
Thomas Borchert (EDDH)

[Ron Natalie]

"John Bell" > wrote in message . com...

>
> Actually, my response to Ron Natalie was a little more than tongue in cheek.
> It was somewhat of a combination of defensiveness and worry that I might be
> spreading bad information. Ron's statement that my explanation of how GPS
> works: "while one of the common ones often espoused
> has no basis in reality. This is not how GPS works" has me curious.
>
The "overlapping spheres" model is NOT how GPS works. It's the same as the
stupid flashing light analogy for VOR. It perhaps gives someone some concept,
but it's not accurate at all. The way GPS works is to use pairs of satellites
to determine hyperbolids which are intersected with ones generated from other
pairs.

[Gene Seibel]

Didn't realize that it took a lot of machismo to determine if a needle
was pointing left or right. But I've been wrong before. ;)
--
Gene Seibel
Hangar 131 - http://pad39a.com/gene/plane.html
Because I fly, I envy no one.



> Gene,
>
> > I guess I still wasn't clear on what I was trying to say. A GPS is
> > great for knowing where you are on a pre-planned course. A GPS moving
> > map isn't good for much of anything.
> >
>
> Well, I couldn't agree less. GPS moving maps are a WONDERFUL tool for
> situational awareness. In fact, beyond the AI, it doesn't get much
> better. If you think wasting your time interpreting arcane needles is
> better, it may be time to tune down the machismo ;-)

[Ron Natalie]

"Mike Beede" > wrote in message ...
> In article >, Ron Natalie > wrote:
>
> > Your information on RAIM is wrong. What is unique about the RAIM used in IFR
> > approved GPS's is not that it determines when the satellite geometry is giving you
> > an error NOW, but computes if it will fail while during the expected duration of flying
> > an instrument approach.
>
> That's RAIM *prediction*. RAIM is very capable of failing during an approach if
> you don't check the prediction ahead of time, at least on our Garmin 430.

Yes...and if you read his document, he doesn't distinguish between RAIM (which many
non-IFR units do just fine) and predictive rain.

[John Bell]

> The "overlapping spheres" model is NOT how GPS works. It's the same as
the
> stupid flashing light analogy for VOR. It perhaps gives someone some
concept,
> but it's not accurate at all. The way GPS works is to use pairs of
satellites
> to determine hyperbolids which are intersected with ones generated from
other
> pairs.
>


Ron,

I looked up some information. I have not had time to completely digest it,
but I do see how a GPS system could be designed to use pairs of satellites
with hyperboloids. I think that my explanation is sufficient for a pilot
level operational understanding of how GPS works. Among other sources
propagating a similar explanation are Trimble and Garmin, so at least I am
in good company. My purpose is to provide a brief conceptual idea of how
GPS works. The primary purpose of my text is to provide practical guidance
as to how to actually use GPS.

Trimble's explanation is at http://www.trimble.com/gps/how.html. And
Garmin's "GPS for Beginners" is available at
http://www.garmin.com/support/userManual.jsp?market=7&subcategory=53&product
=999-99999-20

I did a Google search,
http://www.google.com/search?hl=en&ie=UTF-8&q=hyperboloid+GPS&spell=1 , and
did find some sources indicating that positioning could be done using pairs
of satellites and the intersection of hyperboloids. I am not sure if GPS
receivers actually use the intersecting hyperploids or intersecting sphere
model in their actual design. It appears that both are different techniques
to solve the same problem.

I am not an electrical engineer and am not sure which explanation is correct
or if they are merely different solutions to the same problem. I appreciate
you responding back to explain why you think my explanation was wrong.


John Bell
www.cockpitgps.com

[John Bell]

> > That's RAIM *prediction*. RAIM is very capable of failing during an
approach if
> > you don't check the prediction ahead of time, at least on our Garmin
430.
>
> Yes...and if you read his document, he doesn't distinguish between RAIM
(which many
> non-IFR units do just fine) and predictive rain.
>
Ron,

I am open to argument and corrections of any misunderstandings that I might
have. It was my impression that RAIM is strictly a integrity monitoring
scheme rather than a predictive function. RAIM uses redundant satellite
signals as a cross check to monitor whether any satellite signals are bad.

Since a GPS knows the satellite orbits from the almanac, a program can be
designed to predict if satellite positioning will be adequate to support
RAIM at a given time and place. Receivers such as the Garmin 430 have this
RAIM prediction feature. Knowing the satellite orbit information, it is
also possible to predict and issue a notam for areas and times when RAIM
will be unavailable.

Using the same techniques for predicting RAIM coverage, it would be possible
to warn of impending satellite geometry and coverage problems. I do not
know whether or not any GPS receivers do this automatically beyond the RAIM
prediction program such as in the AUX menu of the Garmins.

I guess I understand RAIM as a monitoring the integrity of the satellite
signal rather than a predictive function. However, I will agree that there
are ways to predict whether or not RAIM will be available.

I am open to corrections if you will explain your reasoning and possibly
site sources.

Thanks,

John Bell

[Ron Natalie]

"John Bell" > wrote in message ...
> > > That's RAIM *prediction*. RAIM is very capable of failing during an
\
> I am open to corrections if you will explain your reasoning and possibly
> site sources.
>
I believe you understand it, now go back and read your book. It is NOT the
presence of RAIM that distinguishes the IFR GPS's (many non-IFR GPS's
also have it), it's the predictive feature that is required/distinguishing.

[Teacherjh]

>>
The way GPS works is to use pairs of
satellites to determine hyperbolids which
are intersected with ones generated from
other pairs.
<<

That's the way sailors do it, but they do it by hand using hyperboloids plotted
on their charts.

If there is a mathematically equivalent way to do it, it might be one that is
easier to program into a box, and maybe that's what an aviation GPS does. If
the alternative is not mathematically equivalent, then one of them is just
wrong.

Jose



--
(for Email, make the obvious changes in my address)

[Larry Dighera]

On Mon, 03 Nov 2003 17:38:07 +0100, Thomas Borchert
> wrote in Message-Id:
>:

>IMHO it [GPS] gives you more than positional awareness.

Aside from ground speed, and three dimensional position (and time of
day), what other information does GPS provide?

Although the aircraft's position is displayed relative to geographical
features (roads, rivers, towns, ...), most GPS databases do not
contain terrain data. GPS doesn't tell you anything about the
powerplant(s), ATC, traffic, fuel, in flight and destination weather,
pilot health, ... which are all part of situational awareness.

Here's one definition of situational awareness:

http://www.refresher.com/!pilot.html
Situational awareness is an ongoing process of the continuous
assessment and accurate interpretation of reality. Effective
environmental scanning when combined with the awareness of the
performance capability of the aircraft, and the self awareness of
personal capabilities and skill of the pilot result in competency
and precision in the execution of maneuvers, and flight safety.


More here:
http://aviation-safety.net/events/FCV.shtml
http://www.acespilotshop.com/pilot-supplies/books/mcgraw-hill-controlling-pilot-error-situational-awareness.htm
http://www.hpti.net/aviation/situational.html

[Thomas Borchert]

Larry,

> Aside from ground speed, and three dimensional position (and time of
> day), what other information does GPS provide?
>

Wind speed and direction, for example.

> GPS doesn't tell you anything about the
>powerplant(s), ATC, traffic, fuel, in flight and destination weather,
>pilot health,

Larry, I never said it would. Not with one word. I know all the stuff
you provided for my education.

Let's stop the nit-picking and get back to the original topic: The
statement was that, while GPS is nice, moving maps don't do much for a
pilot. I disagree. Strongly.

--
Thomas Borchert (EDDH)

[Robert Moore]

Thomas Borchert > wrote

> Wind speed and direction, for example.

How??? By itself, a GPS cannot do this. Only as a part of a
Flight Management System (or similiar NAV System) with an
input of TAS and HDG can wind speed and direction be computed.
A GPS will only provide TRK (course made good) and GS of the
six item wind triangle.... HDG, TAS, TRK, GS, Wind DIR, VEL.

Bob Moore

[Larry Dighera]

On Tue, 04 Nov 2003 16:00:48 +0100, Thomas Borchert
> wrote in Message-Id:
>:

>Larry,
>
>> Aside from ground speed, and three dimensional position (and time of
>> day), what other information does GPS provide?
>>
>
>Wind speed and direction, for example.

I wasn't aware of that. What GPS has the capability to display wind
speed and direction?

>> GPS doesn't tell you anything about the
>>powerplant(s), ATC, traffic, fuel, in flight and destination weather,
>>pilot health,
>
>Larry, I never said it would. Not with one word.

The phrase you used, situational awareness, implies those things.

>I know all the stuff you provided for my education.

Then please display your knowledge of that "stuff" by using the
correct terms.

>Let's stop the nit-picking and get back to the original topic: The
>statement was that, while GPS is nice, moving maps don't do much for a
>pilot. I disagree. Strongly.

Your disagreement is apparent. Unfortunately, in this message thread,
you fail to provide any examples of evidence that supports your
contention.

You contend that moving-map GPS is second only to the AI in its
usefulness, but you don't say how it's useful. Your opinion is always
welcome, of course. But the logic you used to arrive at that opinion
would be significantly more useful information, IMHO.

[Thomas Borchert]

Larry,

Ok, you had your fun jerking my chain, so let's let it go. If you fail
to see the usefulness of a moving map display, I can't help you. Just
don't use one!

--
Thomas Borchert (EDDH)

[C J Campbell]

"Larry Dighera" > wrote in message
...
| On Tue, 04 Nov 2003 16:00:48 +0100, Thomas Borchert
| > wrote in Message-Id:
| >:
|
| >Larry,
| >
| >> Aside from ground speed, and three dimensional position (and time of
| >> day), what other information does GPS provide?
| >>
| >
| >Wind speed and direction, for example.
|
| I wasn't aware of that. What GPS has the capability to display wind
| speed and direction?

Most of them. In fact, I have not seen an aviation GPS which does not have
this capability. However, the feature is invariably so buried in a bunch of
sub-menus that it is almost useless.

[Larry Dighera]

On Tue, 04 Nov 2003 17:44:59 +0100, Thomas Borchert
> wrote in Message-Id:
>:

>Larry,
>
>Ok, you had your fun jerking my chain, so let's let it go.

Sure.

>If you fail to see the usefulness of a moving map display, I can't help you.

That's your inference.

I find the moving-map GPS useful to navigate the KLAX Shoreline
Transition Route. Because ATC demands that you fly directly over the
Pacific shoreline, and it is difficult/impossible to see directly
beneath the aircraft, the GPS display helps. But I wouldn't be
without current paper charts.

>Just don't use one!

I was just trying to understand your rationale. I guess you're
unwilling to share anything other than your opinion. Oh well...

[Newps]

> | >Wind speed and direction, for example.
> |
> | I wasn't aware of that. What GPS has the capability to display wind
> | speed and direction?

All of them. Most if not all the panel mounts will display constant
real time wind direction and speed if you wire in the inputs it needs.
Heading, altitude, etc. Some handhelds can do this but usually you
would just go to the menu and do a one time check of the winds, density
altitude and TAS.

[Larry Dighera]

On Tue, 4 Nov 2003 09:04:37 -0800, "C J Campbell"
> wrote in Message-Id:
>:

>
>"Larry Dighera" > wrote in message
...
>| On Tue, 04 Nov 2003 16:00:48 +0100, Thomas Borchert
>| > wrote in Message-Id:
>| >:
>|
>| >Larry,
>| >
>| >> Aside from ground speed, and three dimensional position (and time of
>| >> day), what other information does GPS provide?
>| >>
>| >
>| >Wind speed and direction, for example.
>|
>| I wasn't aware of that. What GPS has the capability to display wind
>| speed and direction?
>
>Most of them. In fact, I have not seen an aviation GPS which does not have
>this capability. However, the feature is invariably so buried in a bunch of
>sub-menus that it is almost useless.
>

Without a heading information input to the GPS (most handhelds), it
would not seem possible for the GPS to calculate wind speed and
direction. Magic??

[Peter Duniho]

"Larry Dighera" > wrote in message
...
> Without a heading information input to the GPS (most handhelds), it
> would not seem possible for the GPS to calculate wind speed and
> direction. Magic??

Human data entry. Those buttons on the GPS aren't just decoration. They
allow the pilot to pass along useful information to the GPS unit. Like
heading and indicated or true airspeed (I don't know if the aviation GPSs
will do the TAS conversion for you, but there's no reason they
couldn't...you'd just have to enter pressure altitude and temperature as
well).

Pete

[Paul Sengupta]

You type in the info I guess. Heading and airspeed.

Paul

"Larry Dighera" > wrote in message
...
> Without a heading information input to the GPS (most handhelds), it
> would not seem possible for the GPS to calculate wind speed and
> direction. Magic??

[C J Campbell]

"Larry Dighera" > wrote in message
...
..
| >|
| >| I wasn't aware of that. What GPS has the capability to display wind
| >| speed and direction?
| >
| >Most of them. In fact, I have not seen an aviation GPS which does not
have
| >this capability. However, the feature is invariably so buried in a bunch
of
| >sub-menus that it is almost useless.
| >
|
| Without a heading information input to the GPS (most handhelds), it
| would not seem possible for the GPS to calculate wind speed and
| direction. Magic??

Not hardly. Even the panel mounts require manual input. Most of them will
calculate things like pressure altitude and TAS, but you have to dial in all
the info. As I said, it is a pain.

[Larry Dighera]

On Tue, 4 Nov 2003 19:29:00 -0800, "C J Campbell"
> wrote in Message-Id:
>:

>As I said, it is a pain.

Lot's of head-down time I'd expect. That's not prudent in the LA
basin. But it might be more convenient than an E6B on a long leg out
of town.

[Peter Duniho]

"Larry Dighera" > wrote in message
...
> Lot's of head-down time I'd expect. That's not prudent in the LA
> basin.

What do you need winds aloft information for flying in the LA basin?

> But it might be more convenient than an E6B on a long leg out
> of town.

Yes, it would be.

Pete

[karl gruber]

*******Not hardly. Even the panel mounts require manual input. Most of them
will
calculate things like pressure altitude and TAS, but you have to dial in all
the info. As I said, it is a pain.*****

All you need to display a wind arrow is an HSI and an Air Data Computer. All
sorts of airplanes have Honeywell KCS-55A compass systems. Shadin has a low
cost ADC.

Combine heading and TAS and strap them into your Garmin 430/530 and it will
display the wind arrow. At least one truly useful time for that information
is on landing. The arrow will show real time wind shear.

Just bring your checkbook. The new Garmin 1000 system in the new Cessna
182/206 will have all that stuff standard. I do know that Garmin is dragging
their heels, kicking and screaming, in upgrading the 430. They should have
never promised an upgrade for that now antiquated system. An upgrade to the
1000 couldn't cost much more. All the engineering talent is going into the
1000 program. The CNX-80 is a BIG white elephant.

Garmin should offer a 1000 trade up program to the 430/530/80 owners that
they couldn't refuse. It would save a lot of headache. It's already going to
cost a mint to get TAWS, traffic, weather, and VNAV approaches on the older
units anyway.

Karl
"Curator" N185KG

[C J Campbell]

"karl gruber" > wrote in message
...
|
| Garmin should offer a 1000 trade up program to the 430/530/80 owners that
| they couldn't refuse. It would save a lot of headache. It's already going
to
| cost a mint to get TAWS, traffic, weather, and VNAV approaches on the
older
| units anyway.
|

We looked at what such an upgrade would entail. For my 206 we would have to
replace the entire panel.

[Thomas Borchert]

Larry,


> I was just trying to understand your rationale. I guess you're
> unwilling to share anything other than your opinion. Oh well...
>


Ok. My feeling is you're playing dumb. But I've been wrong before. So
one more try at taking you serious. Two examples:

1. VFR
No matter whether you fly over featureless terrain in the Southwest,
the Kansas plains or over water - one glance at the moving map will
tell you where you are, how long it will take you to get anywhere, how
far you are from an airspace border. Granted, you can get all that
information without the map - but it takes much more effort, taken away
from your total mental capacity and thus degrading safety.

2. IFR
Well, take any approach into Podunk field, with no radar coverage and a
ton of step-downs and terrain around you, then add high wind. One
glance at the moving map will tell you where you are with relation to
the approach, the terrain and any navaids. No more figuring out which
side of the protected airspace the wind may have blown you. Granted,
you can get all that information without the map - but it takes much
more effort, taken away from your total mental capacity and thus
degrading safety.

--
Thomas Borchert (EDDH)

[Thomas Borchert]

Larry,

> Lot's of head-down time I'd expect. That's not prudent in the LA
> basin.
>

So you don't do it in the LA basin...

--
Thomas Borchert (EDDH)

[G.R. Patterson III]

C J Campbell wrote:
>
> Not hardly. Even the panel mounts require manual input.

Rocky Mountain Instrument sells a unit that provides your GPS altitude info from
both your altimeter and your encoder, true airspeed, and magnetic heading.
http://www.rkymtn.com

George Patterson
If you're not part of the solution, you can make a lot of money prolonging
the problem.

[Newps]

> "Larry Dighera" > wrote in message
> ...
>
>>Lot's of head-down time I'd expect. That's not prudent in the LA
>>basin.
>
On the Garmin GPS Pilot III you hit the menu button twice, hit the up
arrow button twice and then enter. Now you are at the main screen.
Input a few numbers and you are done. Whole thing takes less than a minute.

[C J Campbell]

"Thomas Borchert" > wrote in message
...
| Larry,
|
| > Lot's of head-down time I'd expect. That's not prudent in the LA
| > basin.
| >
|
| So you don't do it in the LA basin...
|

For that matter, why would you want to?

[Newps]

C J Campbell wrote:

> "Thomas Borchert" > wrote in message
> ...
> | Larry,
> |
> | > Lot's of head-down time I'd expect. That's not prudent in the LA
> | > basin.
> | >
> |
> | So you don't do it in the LA basin...
> |
>
> For that matter, why would you want to?

No ****, what idiot would fly in the LA Basin?

[Tom S.]

"Newps" > wrote in message
news:y0cqb.82096$mZ5.560361@attbi_s54...
>
>
> C J Campbell wrote:
>
> > "Thomas Borchert" > wrote in message
> > ...
> > | Larry,
> > |
> > | > Lot's of head-down time I'd expect. That's not prudent in the LA
> > | > basin.
> > | >
> > |
> > | So you don't do it in the LA basin...
> > |
> >
> > For that matter, why would you want to?
>
> No ****, what idiot would fly in the LA Basin?

A masochistic one.