Accuracy of GPS in Garmin 430/530

[Will]

Is there any way to have the Garmin 430/530 put its current display accuracy
on the primary display as an ongoing statistic, based on the number of
satellites in view? How, in general, do the Garmin units notify you of
situations where GPS accuracy has been compromised to a level that makes it
unsafe to use the Garmin for a GPS approach?

I got an interesting lesson in GPS recently while traveling with a handheld
GPS as the passenger in a plane. The GPS showed us landing about two miles
east of the airport. I figured out only later that the position of the
antenna was such that many satellites were blocked, so the accuracy of the
GPS signal was greatly diminished. The particular software I was using
didn't display its current accuracy on the primary display. Based on that
event, I realize I cannot just trust a GPS display without first
understanding the current accuracy of the signal.

What would be really nice is if the primary display would show vertical and
horizontal accuracy as two separate numbers, based on some high confidence
interval (99.99+%). Knowing that the current display reading is accurate
to 10 ft vertical and 15 ft horizontal, for example, might make you a lot
more comfortable in following a GPS approach than a display where the 99.99%
confidence interval is 2000 ft vertical/horizontal (i.e., GPS reliability is
completely compromised by virtue of blocked satellites, bad GPS antenna,
etc).

--
Will

[Stubby]

Will wrote:
> Is there any way to have the Garmin 430/530 put its current display accuracy
> on the primary display as an ongoing statistic, based on the number of
> satellites in view? How, in general, do the Garmin units notify you of
> situations where GPS accuracy has been compromised to a level that makes it
> unsafe to use the Garmin for a GPS approach?
>
> I got an interesting lesson in GPS recently while traveling with a handheld
> GPS as the passenger in a plane. The GPS showed us landing about two miles
> east of the airport. I figured out only later that the position of the
> antenna was such that many satellites were blocked, so the accuracy of the
> GPS signal was greatly diminished. The particular software I was using
> didn't display its current accuracy on the primary display. Based on that
> event, I realize I cannot just trust a GPS display without first
> understanding the current accuracy of the signal.
>
> What would be really nice is if the primary display would show vertical and
> horizontal accuracy as two separate numbers, based on some high confidence
> interval (99.99+%). Knowing that the current display reading is accurate
> to 10 ft vertical and 15 ft horizontal, for example, might make you a lot
> more comfortable in following a GPS approach than a display where the 99.99%
> confidence interval is 2000 ft vertical/horizontal (i.e., GPS reliability is
> completely compromised by virtue of blocked satellites, bad GPS antenna,
> etc).
>

Do some geocaching in pine forests. You'll see the effect of the trees.
They just cut off the signal and no updates happen for awhile. You
keep on the indicated heading and then all of a sudden the gps catch a
few bits and the arrow flips to a completely new direction!

The gps jocks I've talk to state things like "gps is within 10 meters
95% of the time". I presume that means the gps has a signal. When
it's not getting a signal, I don't think there is much you can say.

[Paul Tomblin]

In a previous article, "Will" > said:
>Is there any way to have the Garmin 430/530 put its current display accuracy
>on the primary display as an ongoing statistic, based on the number of
>satellites in view? How, in general, do the Garmin units notify you of
>situations where GPS accuracy has been compromised to a level that makes it
>unsafe to use the Garmin for a GPS approach?

Google up the term "RAIM warning". All approach certified GPSes have to
warn you if the accuracy is degraded.



--
Paul Tomblin > http://xcski.com/blogs/pt/
"You are a human being, capable of emotions and rational thought. A
computer is only capable of floating point math and crude malice."
http://www.hamsterrepublic.com/james/technomancy/

[Ron Lee]

Another poster correctly pointed you to the real answer: RAIM.

I just wanted to point out that the accuracy of the GPS signal was
never the problem The problem was that you had insufficent signals
for a good solution. RAIM would have detected this and alerted you to
the problem. Thus GPS was never at fault...your user equipment
(including antenna) were not sufficient for the job.

Ron Lee



"Will" > wrote:

>Is there any way to have the Garmin 430/530 put its current display accuracy
>on the primary display as an ongoing statistic, based on the number of
>satellites in view? How, in general, do the Garmin units notify you of
>situations where GPS accuracy has been compromised to a level that makes it
>unsafe to use the Garmin for a GPS approach?
>
>I got an interesting lesson in GPS recently while traveling with a handheld
>GPS as the passenger in a plane. The GPS showed us landing about two miles
>east of the airport. I figured out only later that the position of the
>antenna was such that many satellites were blocked, so the accuracy of the
>GPS signal was greatly diminished. The particular software I was using
>didn't display its current accuracy on the primary display. Based on that
>event, I realize I cannot just trust a GPS display without first
>understanding the current accuracy of the signal.
>
>What would be really nice is if the primary display would show vertical and
>horizontal accuracy as two separate numbers, based on some high confidence
>interval (99.99+%). Knowing that the current display reading is accurate
>to 10 ft vertical and 15 ft horizontal, for example, might make you a lot
>more comfortable in following a GPS approach than a display where the 99.99%
>confidence interval is 2000 ft vertical/horizontal (i.e., GPS reliability is
>completely compromised by virtue of blocked satellites, bad GPS antenna,
>etc).
>
>--
>Will
>
>

[Will]

"Paul Tomblin" > wrote in message
...
> Google up the term "RAIM warning". All approach certified GPSes have to
> warn you if the accuracy is degraded.

I assumed as much, which is why I wanted to know how that condition is
displayed on the Garmin 430/530.

It may just be personal preference, but I see a lot of value in user
interfaces that make the data quality a primary display attribute at all
times. That way I not only know I have a GPS signal, but I can quickly
assess the quality of the signal. I see value in making this more than just
a binary state ("good enough for the FAA" GPS signal quality / "not good
enough for the FAA" GPS signal quality). Possibly that data could be
colored or made to blink in situations where integrity is compromised
sufficiently.

--
Will

[Will]

I guess my wording was not very precise, but I think I already understood
what you are saying here. I was stressing that the GPS' *accuracy* was
compromised, and as you correctly point out the underlying technical reason
for that lowering of accuracy was probably that the number of satellites
that could be seen had lowered. I think signal quality can also factor
into things however. Some of the newer GPS technologies like SiRFXTrac
have the ability to enumerate high-quality signals, low-quality signals, and
remove the lower quality signals from the satellites used in calculations.

I've used XTrac for hiking under forest cover, and it's a marvelous
technology that lets you get a signal reading in situations that would leave
most GPS antennas baffled. XTrac has potential for both lower accuracy and
higher accuracy, since it gives a way to add low-quality signals into the
mix of satellites used in calculations. In reviewing the few GPS
applications I own, I'm pretty surprised that none of them tackles the issue
of data quality head on in a way that makes it immediately obvious to the
user how much accuracy they can expect out of the current signal reading.
Even when you are hiking that is important. But when you look at the
number of PDA and notebook GPS applications that are being developed for
aviation use, it's life-or-death potentially for someone to understand how
much they can rely on the software's display about current position.

I'm no GPS expert, but I have to assume it's straightforward for a GPS to
calculate the number of meters of accuracy to which it can currently
display, given any number of satellites at specific positions and given
specific signal quality for each satellite. Knowing the exact number of
meters of accuracy is for my taste a critical piece of information. I'm
not sure I feel comfortable letting the GPS just take care of my safety by
deducing its conclusions about GPS data quality, even if it is an FAA
approved appliance like the Garmin. Showing accuracy of a displayed
position using a common measure like number of meters for a 99.xx%
confidence interval would give all software packages that display GPS
positions a means of being quickly understood by almost any user who cares
about such things.

--
Will


"Ron Lee" > wrote in message
...
> Another poster correctly pointed you to the real answer: RAIM.
>
> I just wanted to point out that the accuracy of the GPS signal was
> never the problem The problem was that you had insufficent signals
> for a good solution. RAIM would have detected this and alerted you to
> the problem. Thus GPS was never at fault...your user equipment
> (including antenna) were not sufficient for the job.
>
> Ron Lee

[Brad]

Once the 430/530's are upgraded for WAAS, they will have built-in
integrity monitoring and no need for RAIM.

Divorce yourself from the notion that an installed, certified receiver
is the same thing as a handheld gps, pda, whatever. What you're
suggesting regarding horizontal and vertical accuracy is simply
unnecessary. The receiver either meets or does not meet the required
tolerances specified by TSO C129 or TSO C145/146. If it doesn't
sufficient accuracy, it will flag itself. Why do you want something
else to monitor? Do you have a signal strength meter for your nav
receiver?

You mentioned that you were surprised gps software for pda's and pc's
did not have accuracy monitoring and that this was possibly a
life-and-death scenario. This is not the case...non certified software
is for use as a situational awareness aid or for VFR...hardly life or
death. If you're solely using non-approved gps equipment for safety of
life operations, you're seriously acting in a careless and wreckless
manner.

Brad

[Dave S]

Will wrote:
Possibly that data could be
> colored or made to blink in situations where integrity is compromised
> sufficiently.
>

It does.. as previously stated... you get a RAIM warning.

All you need to know is "is the signal performing to a legal/safe
standard" or not. "Good enough for the FAA" is what counts when you are
considering the purpose of a GPS guided instrument approach.

Adding the percentage parameters you envision is just the sort of thing
to add workload to a single pilot IFR approach to minimums. One more
thing to monitor..

Instead, I think the Feds got it right.. either its GOOD or its BAD.
Period.

Dave

[Will]

It's nice that a certified instrument flags an unsafe condition. I would
still like to know the current level of GPS accuracy on a certified
instrument, for many reasons:

* It helps to educate me about GPS and conditions in my immediate
surroundings that might affect accuracy of the technology.

* It helps to alert me about possibly deteriorating conditions, before I get
into a situation where I needed to rely on the instrument and suddenly I
cannot. I wouldn't mind having an indicator about Nav or ILS signal
strength either, by the way, but usually you get that implicitly by noticing
unstable behavior in the Nav needle. What makes GPS a bit more dangerous
is the digital computer display that creates an illusion that everything is
perfectly ordered and working, when in fact the degree of accuracy is
constantly changing. Unlike the analog needle, I don't see any wavering or
other clues about an imminent failure with most GPS applications. I don't
take comfort from knowing that I could get into a GPS approach in bad
weather in a valley with high mountains on all sides and then have the GPS
suddenly announce that it's no longer good enough for the FAA. What if my
exit was a missed approach that is GPS based? The GPS is no longer
approved for the approach, so I'm left with maybe 30 seconds to go over to
another missed approach based on different instruments? It's not making me
feel any better to know that my pilot workload was a lot lower up until the
FAA approved instrument started wailing that I'm in big trouble. If I had
a choice, I would elect the additional pilot workload in order to maintain
additional situation awareness so I can take action in a marginal situation
sooner rather than later.

Regarding non-certified GPS applications: half of these applications
include user testimonials from VFR pilots who go in over their head and who
profusely thank the author of the software for getting them out of a bad
place. Many of these PDAs are being sold with terrain mapping features
that clearly have IFR applications, and while they are never sold as primary
instruments, you must be dreaming if you don't understand that pilots are
buying these things as a last-resort backup instrument should they suffer
catastrophic failures in the other instruments. And why not? The only
time they get used in an IFR application is when all of the FAA certified
instruments have failed and the pilot is in a truly bad way. Any
situational awareness in a situation where you would otherwise have no
situational awareness is better than the alternative.

I would like to see some standards or at least common conventions develop
about how accuracy is reported in the user interface of all types of GPS
applications. And while I respect the right of other pilots to reduce their
workloads by trusting FAA certified instruments and not worrying about
accuracy issues, I personally don't like surprises. I don't see the harm in
revealing the accuracy figures in a simple and easy to understand way for
the pilot who would like to verify the accuracy levels at different phases
of an approach. No one is trying to force it on you. I'm just interested
in having an option.

--
Will


"Brad" > wrote in message
oups.com...
> Once the 430/530's are upgraded for WAAS, they will have built-in
> integrity monitoring and no need for RAIM.
>
> Divorce yourself from the notion that an installed, certified receiver
> is the same thing as a handheld gps, pda, whatever. What you're
> suggesting regarding horizontal and vertical accuracy is simply
> unnecessary. The receiver either meets or does not meet the required
> tolerances specified by TSO C129 or TSO C145/146. If it doesn't
> sufficient accuracy, it will flag itself. Why do you want something
> else to monitor? Do you have a signal strength meter for your nav
> receiver?
>
> You mentioned that you were surprised gps software for pda's and pc's
> did not have accuracy monitoring and that this was possibly a
> life-and-death scenario. This is not the case...non certified software
> is for use as a situational awareness aid or for VFR...hardly life or
> death. If you're solely using non-approved gps equipment for safety of
> life operations, you're seriously acting in a careless and wreckless
> manner.
>
> Brad
>

[Jim Macklin]

If you're in flight you will have nothing above your
antennas to block reception [unless you fly by GPS while
refueling]. If you are, like a hiker shielded by trees,
you'd better not be looking at your GPS, you have more
serious troubles.

RAIM does the job, you might read the section in the manual
about RAIM, see the Garmin manual, on-line manual...


--
James H. Macklin
ATP,CFI,A&P

--
The people think the Constitution protects their rights;
But government sees it as an obstacle to be overcome.
some support
http://www.usdoj.gov/olc/secondamendment2.htm
See http://www.fija.org/ more about your rights and duties.



"Will" > wrote in message
...
|I guess my wording was not very precise, but I think I
already understood
| what you are saying here. I was stressing that the GPS'
*accuracy* was
| compromised, and as you correctly point out the underlying
technical reason
| for that lowering of accuracy was probably that the number
of satellites
| that could be seen had lowered. I think signal quality
can also factor
| into things however. Some of the newer GPS technologies
like SiRFXTrac
| have the ability to enumerate high-quality signals,
low-quality signals, and
| remove the lower quality signals from the satellites used
in calculations.
|
| I've used XTrac for hiking under forest cover, and it's a
marvelous
| technology that lets you get a signal reading in
situations that would leave
| most GPS antennas baffled. XTrac has potential for both
lower accuracy and
| higher accuracy, since it gives a way to add low-quality
signals into the
| mix of satellites used in calculations. In reviewing the
few GPS
| applications I own, I'm pretty surprised that none of them
tackles the issue
| of data quality head on in a way that makes it immediately
obvious to the
| user how much accuracy they can expect out of the current
signal reading.
| Even when you are hiking that is important. But when you
look at the
| number of PDA and notebook GPS applications that are being
developed for
| aviation use, it's life-or-death potentially for someone
to understand how
| much they can rely on the software's display about current
position.
|
| I'm no GPS expert, but I have to assume it's
straightforward for a GPS to
| calculate the number of meters of accuracy to which it can
currently
| display, given any number of satellites at specific
positions and given
| specific signal quality for each satellite. Knowing the
exact number of
| meters of accuracy is for my taste a critical piece of
information. I'm
| not sure I feel comfortable letting the GPS just take care
of my safety by
| deducing its conclusions about GPS data quality, even if
it is an FAA
| approved appliance like the Garmin. Showing accuracy of
a displayed
| position using a common measure like number of meters for
a 99.xx%
| confidence interval would give all software packages that
display GPS
| positions a means of being quickly understood by almost
any user who cares
| about such things.
|
| --
| Will
|
|
| "Ron Lee" > wrote in message
| ...
| > Another poster correctly pointed you to the real answer:
RAIM.
| >
| > I just wanted to point out that the accuracy of the GPS
signal was
| > never the problem The problem was that you had
insufficent signals
| > for a good solution. RAIM would have detected this and
alerted you to
| > the problem. Thus GPS was never at fault...your user
equipment
| > (including antenna) were not sufficient for the job.
| >
| > Ron Lee
|
|

[Sam Spade]

Will wrote:
> Is there any way to have the Garmin 430/530 put its current display accuracy
> on the primary display as an ongoing statistic, based on the number of
> satellites in view? How, in general, do the Garmin units notify you of
> situations where GPS accuracy has been compromised to a level that makes it
> unsafe to use the Garmin for a GPS approach?

Why would you want that information? In single-pilot operations,
especially, looking at those data constitutes information overload.
That is what RAIM is all about, to keep it simple. RAIM is much more
robust for the final approach segment than for terminal mode. You
simply aren't going to have issues with an IFR-certified GPS (properly
installed) that you will have with a hand-held.
>
> I got an interesting lesson in GPS recently while traveling with a handheld
> GPS as the passenger in a plane. The GPS showed us landing about two miles
> east of the airport. I figured out only later that the position of the
> antenna was such that many satellites were blocked, so the accuracy of the
> GPS signal was greatly diminished.

That large of an error was probably due to the substantial altitude
change of the airliner while your GPS was staggering along in 2-D mode.

The particular software I was using
> didn't display its current accuracy on the primary display. Based on that
> event, I realize I cannot just trust a GPS display without first
> understanding the current accuracy of the signal.

As others have told you, the portable does not have RAIM. It is a VFR
device. It was not designed to be robust through a cabin window of an
airliner. Some owners, who are savvy on this still, install an external
antenna on their aircraft for their hand-held GPS. It will never have
the problems you experienced with an external antenna.
>
> What would be really nice is if the primary display would show vertical and
> horizontal accuracy as two separate numbers, based on some high confidence
> interval (99.99+%). Knowing that the current display reading is accurate
> to 10 ft vertical and 15 ft horizontal, for example, might make you a lot
> more comfortable in following a GPS approach than a display where the 99.99%
> confidence interval is 2000 ft vertical/horizontal (i.e., GPS reliability is
> completely compromised by virtue of blocked satellites, bad GPS antenna,
> etc).
>

Again, RAIM and proper IFR installation procedures mitigate your
concerns to the point of being irrelevant.

There is different, higher level of accuracy, integrity, and continuity
than "plain vanilla" TSO-C129 IFR GPS. That is an IFR-approved RNP
platform, which is a quandum leap in RNAV integrity. RNP platforms have
enough information to make you happy in your quest. But, the displays
and software are presently heavy iron stuff, and huge overkill for most
IFR operations today.

[Roy Smith]

"Will" > wrote:
> It may just be personal preference, but I see a lot of value in user
> interfaces that make the data quality a primary display attribute at all
> times. That way I not only know I have a GPS signal, but I can quickly
> assess the quality of the signal. I see value in making this more than just
> a binary state ("good enough for the FAA" GPS signal quality / "not good
> enough for the FAA" GPS signal quality). Possibly that data could be
> colored or made to blink in situations where integrity is compromised
> sufficiently.

I disagree. We already have information overload. A binary "go/no-go" is
exactly what you want. If I told you that the SNR from satellite 17 was
down 6dB, what would you do with that information?

RAIM factors in signal strength as well as satellite geometry. To get a
good fix, you need to be getting a good signal from 4 satellites positioned
appropriately in both azimuth and elevation. Figuring out if the signal
strength and geometry is "good enough" is not the kind of problem people
can do in their heads.

[Roy Smith]

"Will" > wrote:

> It's nice that a certified instrument flags an unsafe condition. I would
> still like to know the current level of GPS accuracy on a certified
> instrument, for many reasons:
>
> * It helps to educate me about GPS and conditions in my immediate
> surroundings that might affect accuracy of the technology.
>
> * It helps to alert me about possibly deteriorating conditions, before I get
> into a situation where I needed to rely on the instrument and suddenly I
> cannot.

A handheld GPS used by a hiker in the woods is working under completely
different environmental conditions than one on an airplane. The biggest
reason for a hiker's GPS to get poor signal is because of nearby terrain or
overhead foliage blocking line of site to the sky.

By the time an airplane's view of the sky is blocked by overhead foliage,
they've probably got bigger problems than not having a good GPS signal.

[John Theune]

Roy Smith wrote:
> "Will" > wrote:
>
>>It may just be personal preference, but I see a lot of value in user
>>interfaces that make the data quality a primary display attribute at all
>>times. That way I not only know I have a GPS signal, but I can quickly
>>assess the quality of the signal. I see value in making this more than just
>>a binary state ("good enough for the FAA" GPS signal quality / "not good
>>enough for the FAA" GPS signal quality). Possibly that data could be
>>colored or made to blink in situations where integrity is compromised
>>sufficiently.
>
>
> I disagree. We already have information overload. A binary "go/no-go" is
> exactly what you want. If I told you that the SNR from satellite 17 was
> down 6dB, what would you do with that information?
>
> RAIM factors in signal strength as well as satellite geometry. To get a
> good fix, you need to be getting a good signal from 4 satellites positioned
> appropriately in both azimuth and elevation. Figuring out if the signal
> strength and geometry is "good enough" is not the kind of problem people
> can do in their heads.
I'm somewhat surprised that no one has mentioned that both the Garmin
and Lowrance units that I'm familiar with have a page for satelitte
signal strength. I've never felt the need to run thru the 430/530 pages
to find a similar page but would not be surprised to find it buried in
there somewhere. To answer the OP's question it's there you just need
to read the manual to find which sub-menu it's on. If he's using a
non-aviation unit then all bets are off but again I would think it would
be there somewhere. Also on the units I use regularly the airplane icon
flashs on the main display when the signal is lost ala a pseudo RAIM
indicator

[Sam Spade]

John Theune wrote:
..
>
> I'm somewhat surprised that no one has mentioned that both the Garmin
> and Lowrance units that I'm familiar with have a page for satelitte
> signal strength.

Page 4 of the nav section.

[Mark Hansen]

On 04/25/06 05:03, John Theune wrote:
> Roy Smith wrote:
>> "Will" > wrote:
>>
>>>It may just be personal preference, but I see a lot of value in user
>>>interfaces that make the data quality a primary display attribute at all
>>>times. That way I not only know I have a GPS signal, but I can quickly
>>>assess the quality of the signal. I see value in making this more than just
>>>a binary state ("good enough for the FAA" GPS signal quality / "not good
>>>enough for the FAA" GPS signal quality). Possibly that data could be
>>>colored or made to blink in situations where integrity is compromised
>>>sufficiently.
>>
>>
>> I disagree. We already have information overload. A binary "go/no-go" is
>> exactly what you want. If I told you that the SNR from satellite 17 was
>> down 6dB, what would you do with that information?
>>
>> RAIM factors in signal strength as well as satellite geometry. To get a
>> good fix, you need to be getting a good signal from 4 satellites positioned
>> appropriately in both azimuth and elevation. Figuring out if the signal
>> strength and geometry is "good enough" is not the kind of problem people
>> can do in their heads.
> I'm somewhat surprised that no one has mentioned that both the Garmin
> and Lowrance units that I'm familiar with have a page for satelitte
> signal strength. I've never felt the need to run thru the 430/530 pages
> to find a similar page but would not be surprised to find it buried in
> there somewhere. To answer the OP's question it's there you just need
> to read the manual to find which sub-menu it's on. If he's using a
> non-aviation unit then all bets are off but again I would think it would
> be there somewhere. Also on the units I use regularly the airplane icon
> flashs on the main display when the signal is lost ala a pseudo RAIM
> indicator

The OP was asking why this can't be displayed on the main page...

You snipped it from your response. Here it is:

> Is there any way to have the Garmin 430/530 put its current display accuracy
> on the primary display as an ongoing statistic, based on the number of
> satellites in view?




--
Mark Hansen, PP-ASEL, Instrument Airplane
Cal Aggie Flying Farmers
Sacramento, CA

[Brad]

"* It helps to educate me about GPS and conditions in my immediate
surroundings that might affect accuracy of the technology.
* It helps to alert me about possibly deteriorating conditions, before
I get into a situation where I needed to rely on the instrument and
suddenly I cannot."

In an airplane, your immediate surroundings should have no bearing on
your GPS accuracy unless you're flying under bridges, trees, through
tunnels...you get the idea. Keep in mind that the GPS constellation is
constantly moving so there are no dead areas, like you might have with
a VOR signal. I'm not sure what you mean by deteriorating
conditions...how is your meter going to predict ionospheric activity or
a satellite going off line? It's not like bars on a cell phone.

Regarding standards for handheld GPS, who would enforce the standards?
What if a particular receiver did meet the standards?

[Will]

"Roy Smith" > wrote in message
...
> I disagree. We already have information overload. A binary "go/no-go" is
> exactly what you want. If I told you that the SNR from satellite 17 was
> down 6dB, what would you do with that information?

That's not useful information the way you present it. I want conclusions
and not data. Specifically I want to know the number of feet/meters of
accuracy of my current position, that's all. If my current accuracy is 10
ft vertical versus 100 ft vertical versus 1000 ft vertical, that means
something to me about how much trust I should put in the GPS display.

--
Will

[Will]

"John Theune" > wrote in message
news:Udo3g.5009$bU6.3635@trnddc06...
> I'm somewhat surprised that no one has mentioned that both the Garmin
> and Lowrance units that I'm familiar with have a page for satelitte
> signal strength. I've never felt the need to run thru the 430/530 pages
> to find a similar page but would not be surprised to find it buried in
> there somewhere. To answer the OP's question it's there you just need
> to read the manual to find which sub-menu it's on. If he's using a
> non-aviation unit then all bets are off but again I would think it would
> be there somewhere. Also on the units I use regularly the airplane icon
> flashs on the main display when the signal is lost ala a pseudo RAIM
> indicator

You are right all GPS software usually implements a satellite signal page.
It's not in any way shape or form what I asked for.

I want the GPS to take all of the inputs for number of satellites and signal
strength and derive from that just two integers:

1) Number of feet/meters of horizontal accuracy, within some confidence
interval (e.g., 99.95%)

2) Number of feet/meters of vertical accuracy, within some confidence
interval (e.g., 99.95%)

Those two numbers could become optional numbers for the primary display.
No one is forcing anyone to use them. If you want to simply trust the
instrument to give you a go-nogo decision, it's your life and if you feel
that is safe it's a free world (as long as you follow FAA rules :) ) so be
my guest.

For my personal taste, I understand that a GPS display is always an illusion
subject to different levels of inaccuracy. I am sensitive to the
difference between a display that is showing me accuracy to 10 ft, 100 ft,
or 1000 ft. In the original posted example the GPS was off target by more
than 5000 ft. Nothing on the original display gave me any clue that this
was the case. The two numbers I am asking for would communicate quite
succinctly that no one should rely on the display for anything other than
the most gross kind of positioning.

While I would love to see the feature I am looking for in any FAA-compliant
instrument like a Garmin 530, I think the feature becomes most critical in
non-FAA compliant GPS devices/software. The authors of such packages
cannot control the quality of the satellite antenna, or mounting, and
substandard GPS reception is probably a routine thing for PDA based GPS
devices/software. So finding a succinct way to communicate the accuracy of
the current signal in numbers that mean something to any user becomes quite
important. Making people look at satellite maps and signal strength seems
like a pure engineering exercise, and it doesn't collapse the input data
into a useful form.

--
Will

[Will]

"Roy Smith" > wrote in message
...
> A handheld GPS used by a hiker in the woods is working under completely
> different environmental conditions than one on an airplane. The biggest
> reason for a hiker's GPS to get poor signal is because of nearby terrain
or
> overhead foliage blocking line of site to the sky.
>
> By the time an airplane's view of the sky is blocked by overhead foliage,
> they've probably got bigger problems than not having a good GPS signal.

For an FAA-approved device, properly installed, I think you are right
probably 99% of the time. Of course even then you could imagine cases like
what happens if the GPS antenna starts to slowly go bad? You don't want to
learn about that when it reaches a critical failure point in the final part
of an approach. Better to see the accuracy start out at 20 ft accuracy and
slip over time to 50 ft, 80 ft, 100 ft, etc. Over many flights even an
inobservant person might catch the deterioration and do something about it
when there is time.

For a non-FAA approved device, I think you are wrong. The problem here is
that the GPS software has no way to guarantee the integrity of the satellite
antenna, and very importantly it cannot guarantee the integrity of the
antenna's placement within the cockpit. If the user accidentally selects
XTrac mode without understanding the implications of that, places the
antenna out of view of most satellites within the cockpit, etc, the software
happily displays an aircraft position. And it never tells you that your
current position is only accurate to 10,000 ft horizontal!

The point is that in a non-approved device, the GPS software creates an
illusion that you are on a 2D map position, at a spacial coordinate, but
most of this software gives you no immediate way to determine if that
reading is accurate to 10 ft or 10K ft. Knowing in advance that you are
accurate to only 10K ft would probably give most pilots a reason to
investigate why, maybe resulting in a better position for the antenna, for
example. Maybe the user would find out that they had accidentally left the
unit in XTrac mode and they need to switch over to a more accurate mode.
Better to make these discoveries and tinker with such things in a calm
environment. You don't want to make the discovery that the "backup" GPS
display is worthless on the day you lose all your primary instruments in IFR
conditions.

I just don't understand the issue about pilot overload. I'm asking for two
integers, and you don't need to look at them ever if you don't want to.

--
Will

[Will]

"Brad" > wrote in message
ups.com...
> In an airplane, your immediate surroundings should have no bearing on
> your GPS accuracy unless you're flying under bridges, trees, through
> tunnels...you get the idea. Keep in mind that the GPS constellation is
> constantly moving so there are no dead areas, like you might have with
> a VOR signal. I'm not sure what you mean by deteriorating
> conditions...how is your meter going to predict ionospheric activity or
> a satellite going off line? It's not like bars on a cell phone.

For non-FAA rated GPS devices, it's not hard to get a bad GPS signal that is
highly inaccurate. It's not always the case that you just get a signal
failure or a good signal. Some of these GPS antennas are getting extremely
good at giving you a reading in spite of a bad positioning that blocks
important parts of the sky.


> Regarding standards for handheld GPS, who would enforce the standards?
> What if a particular receiver did meet the standards?

Given some number of satellites, each with a given signal quality, I think
any GPS software could make statistical calculations that would result in
two numbers for number of feet of horizontal and vertical accuracy, to some
confidence interval. How do you guarantee that the author of the software
does the math correctly? I guess you can't except by cross reference to
other devices. But the same complaint could be made about any other part
of the software. How do you know he converted spacial coordinates from the
GPS to a correct map position? No doubt there could be errors in the
implementation of those algorithms, as with any other algorithm.

--
Will

[Will]

"Sam Spade" > wrote in message
news:l8n3g.174223$bm6.98713@fed1read04...
> > I got an interesting lesson in GPS recently while traveling with a
handheld
> > GPS as the passenger in a plane. The GPS showed us landing about two
miles
> > east of the airport. I figured out only later that the position of the
> > antenna was such that many satellites were blocked, so the accuracy of
the
> > GPS signal was greatly diminished.
>
> That large of an error was probably due to the substantial altitude
> change of the airliner while your GPS was staggering along in 2-D mode.

I think the reason may have been that most satellites were blocked inside
the cockpit. But why would anyone object to this non-FAA software simply
self-reporting that its current accuracy was some huge number of horizontal
and vertical feet (i.e., that it was not currently very accurate)? I
cannot understand why anyone would feel that this is a bad thing to tell a
user of that device. If you don't want the information then ignore it.


> airliner. Some owners, who are savvy on this still, install an external
> antenna on their aircraft for their hand-held GPS. It will never have
> the problems you experienced with an external antenna.

That's a great idea. Maybe more handheld GPS users would become aware of
the need for for an external antenna if their GPS software clearly
communicated when the signals they are getting are not very accurate? That
fact might inspire more users of these devices to understand that antenna
placement is quite critical for these devices.

--
Will

[John Theune]

Will wrote:
> "John Theune" > wrote in message
> news:Udo3g.5009$bU6.3635@trnddc06...
>
>>I'm somewhat surprised that no one has mentioned that both the Garmin
>>and Lowrance units that I'm familiar with have a page for satelitte
>>signal strength. I've never felt the need to run thru the 430/530 pages
>>to find a similar page but would not be surprised to find it buried in
>>there somewhere. To answer the OP's question it's there you just need
>>to read the manual to find which sub-menu it's on. If he's using a
>>non-aviation unit then all bets are off but again I would think it would
>>be there somewhere. Also on the units I use regularly the airplane icon
>>flashs on the main display when the signal is lost ala a pseudo RAIM
>>indicator
>
>
> You are right all GPS software usually implements a satellite signal page.
> It's not in any way shape or form what I asked for.
>
> I want the GPS to take all of the inputs for number of satellites and signal
> strength and derive from that just two integers:
>
> 1) Number of feet/meters of horizontal accuracy, within some confidence
> interval (e.g., 99.95%)
>
> 2) Number of feet/meters of vertical accuracy, within some confidence
> interval (e.g., 99.95%)
>
> Those two numbers could become optional numbers for the primary display.
> No one is forcing anyone to use them. If you want to simply trust the
> instrument to give you a go-nogo decision, it's your life and if you feel
> that is safe it's a free world (as long as you follow FAA rules :) ) so be
> my guest.
>
> For my personal taste, I understand that a GPS display is always an illusion
> subject to different levels of inaccuracy. I am sensitive to the
> difference between a display that is showing me accuracy to 10 ft, 100 ft,
> or 1000 ft. In the original posted example the GPS was off target by more
> than 5000 ft. Nothing on the original display gave me any clue that this
> was the case. The two numbers I am asking for would communicate quite
> succinctly that no one should rely on the display for anything other than
> the most gross kind of positioning.
>
> While I would love to see the feature I am looking for in any FAA-compliant
> instrument like a Garmin 530, I think the feature becomes most critical in
> non-FAA compliant GPS devices/software. The authors of such packages
> cannot control the quality of the satellite antenna, or mounting, and
> substandard GPS reception is probably a routine thing for PDA based GPS
> devices/software. So finding a succinct way to communicate the accuracy of
> the current signal in numbers that mean something to any user becomes quite
> important. Making people look at satellite maps and signal strength seems
> like a pure engineering exercise, and it doesn't collapse the input data
> into a useful form.
>
And right on that same page for the Lowrance unit is the EPE ( Estimated
Probability of Error ) in feet for the current location. The EPE is for
horizontal accuracy as the vertical accuracy is mostly meaningless for
GPS as they can only give you vertical guidance from a perfect sphere
and the earth does not quite fit that. vertical accuracy would require
the GPS to have a complete model of the earth elevation and coralate
that to the horizontal location so as to determine the actual vertical
location vs calculated position. Now I spent a few moments messing with
my unit and found that I can place the EPE on the main map page along
side course, heading , speed and so forth. If you want to know more I
suggest you look at the manual for your system.

[Jose]

> But why would anyone object to this non-FAA software simply
> self-reporting that its current accuracy was some huge number of horizontal
> and vertical feet (i.e., that it was not currently very accurate)?

Because it's a source of more bugs.

Jose
--
The price of freedom is... well... freedom.
for Email, make the obvious change in the address.

[Jim Macklin]

Read the TSO and then read the description of RAIM other
accuracy monitoring software built into the unit.



--
James H. Macklin
ATP,CFI,A&P

"Will" > wrote in message
...
|
| "John Theune" > wrote in message
| news:Udo3g.5009$bU6.3635@trnddc06...
| > I'm somewhat surprised that no one has mentioned that
both the Garmin
| > and Lowrance units that I'm familiar with have a page
for satelitte
| > signal strength. I've never felt the need to run thru
the 430/530 pages
| > to find a similar page but would not be surprised to
find it buried in
| > there somewhere. To answer the OP's question it's there
you just need
| > to read the manual to find which sub-menu it's on. If
he's using a
| > non-aviation unit then all bets are off but again I
would think it would
| > be there somewhere. Also on the units I use regularly
the airplane icon
| > flashs on the main display when the signal is lost ala a
pseudo RAIM
| > indicator
|
| You are right all GPS software usually implements a
satellite signal page.
| It's not in any way shape or form what I asked for.
|
| I want the GPS to take all of the inputs for number of
satellites and signal
| strength and derive from that just two integers:
|
| 1) Number of feet/meters of horizontal accuracy, within
some confidence
| interval (e.g., 99.95%)
|
| 2) Number of feet/meters of vertical accuracy, within some
confidence
| interval (e.g., 99.95%)
|
| Those two numbers could become optional numbers for the
primary display.
| No one is forcing anyone to use them. If you want to
simply trust the
| instrument to give you a go-nogo decision, it's your life
and if you feel
| that is safe it's a free world (as long as you follow FAA
rules :) ) so be
| my guest.
|
| For my personal taste, I understand that a GPS display is
always an illusion
| subject to different levels of inaccuracy. I am
sensitive to the
| difference between a display that is showing me accuracy
to 10 ft, 100 ft,
| or 1000 ft. In the original posted example the GPS was
off target by more
| than 5000 ft. Nothing on the original display gave me
any clue that this
| was the case. The two numbers I am asking for would
communicate quite
| succinctly that no one should rely on the display for
anything other than
| the most gross kind of positioning.
|
| While I would love to see the feature I am looking for in
any FAA-compliant
| instrument like a Garmin 530, I think the feature becomes
most critical in
| non-FAA compliant GPS devices/software. The authors of
such packages
| cannot control the quality of the satellite antenna, or
mounting, and
| substandard GPS reception is probably a routine thing for
PDA based GPS
| devices/software. So finding a succinct way to
communicate the accuracy of
| the current signal in numbers that mean something to any
user becomes quite
| important. Making people look at satellite maps and
signal strength seems
| like a pure engineering exercise, and it doesn't collapse
the input data
| into a useful form.
|
| --
| Will
|
|
|
|

[Jim Macklin]

And it could double the cost of the system for no useful
purpose.


I'm sure that if anybody wanted a custom made GPS unit,
Garmin or some other company would be happy to take your
million dollars and build you one or even two of them.



--
James H. Macklin
ATP,CFI,A&P

--
The people think the Constitution protects their rights;
But government sees it as an obstacle to be overcome.
some support
http://www.usdoj.gov/olc/secondamendment2.htm
See http://www.fija.org/ more about your rights and duties.


"Jose" > wrote in message
. com...
|> But why would anyone object to this non-FAA software
simply
| > self-reporting that its current accuracy was some huge
number of horizontal
| > and vertical feet (i.e., that it was not currently very
accurate)?
|
| Because it's a source of more bugs.
|
| Jose
| --
| The price of freedom is... well... freedom.
| for Email, make the obvious change in the address.

[Bob Gardner]

You will never get the display you are looking for in a handheld device.
IMHO handhelds will never have RAIM.

Bob Gardner

"Will" > wrote in message
...
>
> "John Theune" > wrote in message
> news:Udo3g.5009$bU6.3635@trnddc06...
>> I'm somewhat surprised that no one has mentioned that both the Garmin
>> and Lowrance units that I'm familiar with have a page for satelitte
>> signal strength. I've never felt the need to run thru the 430/530 pages
>> to find a similar page but would not be surprised to find it buried in
>> there somewhere. To answer the OP's question it's there you just need
>> to read the manual to find which sub-menu it's on. If he's using a
>> non-aviation unit then all bets are off but again I would think it would
>> be there somewhere. Also on the units I use regularly the airplane icon
>> flashs on the main display when the signal is lost ala a pseudo RAIM
>> indicator
>
> You are right all GPS software usually implements a satellite signal page.
> It's not in any way shape or form what I asked for.
>
> I want the GPS to take all of the inputs for number of satellites and
> signal
> strength and derive from that just two integers:
>
> 1) Number of feet/meters of horizontal accuracy, within some confidence
> interval (e.g., 99.95%)
>
> 2) Number of feet/meters of vertical accuracy, within some confidence
> interval (e.g., 99.95%)
>
> Those two numbers could become optional numbers for the primary display.
> No one is forcing anyone to use them. If you want to simply trust the
> instrument to give you a go-nogo decision, it's your life and if you feel
> that is safe it's a free world (as long as you follow FAA rules :) ) so
> be
> my guest.
>
> For my personal taste, I understand that a GPS display is always an
> illusion
> subject to different levels of inaccuracy. I am sensitive to the
> difference between a display that is showing me accuracy to 10 ft, 100 ft,
> or 1000 ft. In the original posted example the GPS was off target by
> more
> than 5000 ft. Nothing on the original display gave me any clue that this
> was the case. The two numbers I am asking for would communicate quite
> succinctly that no one should rely on the display for anything other than
> the most gross kind of positioning.
>
> While I would love to see the feature I am looking for in any
> FAA-compliant
> instrument like a Garmin 530, I think the feature becomes most critical in
> non-FAA compliant GPS devices/software. The authors of such packages
> cannot control the quality of the satellite antenna, or mounting, and
> substandard GPS reception is probably a routine thing for PDA based GPS
> devices/software. So finding a succinct way to communicate the accuracy
> of
> the current signal in numbers that mean something to any user becomes
> quite
> important. Making people look at satellite maps and signal strength
> seems
> like a pure engineering exercise, and it doesn't collapse the input data
> into a useful form.
>
> --
> Will
>
>
>
>

[Will]

As the lawyers like to say in court "evidence not in the record." There
is no proof at all for the claim that some straightforward math calculations
in any GPS software is going to to double the cost of the GPS. What I was
describing doesn't require any new hardware, and it's just a matter of
calculating some accuracy numbers and representing them in the standard UI.

If it prevents one death that results in a multi-million dollar lawsuit, it
would payback the one man-month of work it might take to do those
calculations in software 100 fold or more.

--
Will


"Jim Macklin" > wrote in message
news:4bx3g.8797$ZW3.1447@dukeread04...
> And it could double the cost of the system for no useful
> purpose.
>
> I'm sure that if anybody wanted a custom made GPS unit,
> Garmin or some other company would be happy to take your
> million dollars and build you one or even two of them.
>
> --
> James H. Macklin
> ATP,CFI,A&P

[Dave S]

Will wrote:
> As the lawyers like to say in court "evidence not in the record." There
> is no proof at all for the claim that some straightforward math calculations
> in any GPS software is going to to double the cost of the GPS. What I was
> describing doesn't require any new hardware, and it's just a matter of
> calculating some accuracy numbers and representing them in the standard UI.
>
> If it prevents one death that results in a multi-million dollar lawsuit, it
> would payback the one man-month of work it might take to do those
> calculations in software 100 fold or more.
>

How would the use of the GPS be responsible for someone's death?

For VFR work, handeld or otherwise, GPS is an advisory system only, and
not guaranteed. User beware. Have alternative nav sources, like people
did for decades before GPS came on the scene. Did you read the
dislaimers on your GPS's packaging when you got it? Didn't read em? Too
bad.. Didn't buy it new and have the original packaging? Still your
problem. And being in VFR.. you shouldnt have to worry about conditions
bad enough to require an approach.

For IFR work, either you have a good signal, or you do NOT have a good
signal (as calculated by your reciever, and displayed in the form of a
RAIM integrity warning). No shades of gray here.

Based on the past few days worth of posts.. I'm guessing you haven't
done much in the way of actual IFR approaches to minimums.. and I am
also predicting you've not done any of it behind IFR approved GPS
devices, after having thoroughly read the manual and recieved training
in such... workload and workload reduction is crucial. What you propose
is to add workload, unnecesarily, to give quanititative data (percentage
points/errors) regarding something that is already addressed in a
qualitative manner (RAIM OK or NOT OK).

Now you try to justify its cost/benefit by a hypothetical lawsuit over
the lack of something that is not mandated, not needed and not justified?

Sorry... doesn't add up.
Dave

[J. Severyn]

Well you get a real-time calculated number in the horizontal direction,

http://www.garmin.com/manuals/GNS430_PilotsGuide.pdf pages 44, 46
and
http://www.garmin.com/manuals/GNS530_PilotsGuide.pdf page 43

Garmin calculates the Estimated Position Error (in feet or meters
horizontally), but does not present an estimate of the vertical error. I
believe Garmin has done this on most if not all of their aviation units,
handheld and panel mount. I've got an old GPS95XL and it does the same
thing.

Regards,
John Severyn @KLVK


"Will" > wrote in message
...
> Is there any way to have the Garmin 430/530 put its current display
> accuracy
> on the primary display as an ongoing statistic, based on the number of
> satellites in view? How, in general, do the Garmin units notify you of
> situations where GPS accuracy has been compromised to a level that makes
> it
> unsafe to use the Garmin for a GPS approach?
>
> I got an interesting lesson in GPS recently while traveling with a
> handheld
> GPS as the passenger in a plane. The GPS showed us landing about two
> miles
> east of the airport. I figured out only later that the position of the
> antenna was such that many satellites were blocked, so the accuracy of the
> GPS signal was greatly diminished. The particular software I was using
> didn't display its current accuracy on the primary display. Based on
> that
> event, I realize I cannot just trust a GPS display without first
> understanding the current accuracy of the signal.
>
> What would be really nice is if the primary display would show vertical
> and
> horizontal accuracy as two separate numbers, based on some high confidence
> interval (99.99+%). Knowing that the current display reading is accurate
> to 10 ft vertical and 15 ft horizontal, for example, might make you a lot
> more comfortable in following a GPS approach than a display where the
> 99.99%
> confidence interval is 2000 ft vertical/horizontal (i.e., GPS reliability
> is
> completely compromised by virtue of blocked satellites, bad GPS antenna,
> etc).
>
> --
> Will
>
>

[Jim Macklin]

you do it, you built it and get rich.
"Will" > wrote in message
...
| As the lawyers like to say in court "evidence not in the
record." There
| is no proof at all for the claim that some straightforward
math calculations
| in any GPS software is going to to double the cost of the
GPS. What I was
| describing doesn't require any new hardware, and it's just
a matter of
| calculating some accuracy numbers and representing them in
the standard UI.
|
| If it prevents one death that results in a multi-million
dollar lawsuit, it
| would payback the one man-month of work it might take to
do those
| calculations in software 100 fold or more.
|
| --
| Will
|
|
| "Jim Macklin" > wrote
in message
| news:4bx3g.8797$ZW3.1447@dukeread04...
| > And it could double the cost of the system for no useful
| > purpose.
| >
| > I'm sure that if anybody wanted a custom made GPS unit,
| > Garmin or some other company would be happy to take your
| > million dollars and build you one or even two of them.
| >
| > --
| > James H. Macklin
| > ATP,CFI,A&P
|
|

[Jose]

> There
> is no proof at all for the claim that some straightforward math calculations
> in any GPS software is going to to double the cost of the GPS.

Have you ever written software?

> If it prevents one death that results in a multi-million dollar lawsuit, it
> would payback the one man-month of work it might take to do those
> calculations in software 100 fold or more.

It is actually more likely to =cause= a death - to a pilot who decides
to rely on a handheld because it has RAIM.

Jose
--
The price of freedom is... well... freedom.
for Email, make the obvious change in the address.

[Roy Smith]

In article >,
Jose > wrote:

> It is actually more likely to =cause= a death - to a pilot who decides
> to rely on a handheld because it has RAIM.
>
> Jose

And tell me that pilots aren't already using those "for situational
awareness only" extended runway centerlines drawn on the moving maps of
VFR-only handhelds to cobble up their own instrument approaches?

[Jose]

> And tell me that pilots aren't already using those "for situational
> awareness only" extended runway centerlines drawn on the moving maps of
> VFR-only handhelds to cobble up their own instrument approaches?

.... and tell me that one day some widow is going to sue, and the chance
of her winning is on the heads or tails of a token.

Now, without RAIM the defense "it was VFR only, that was an SPT" holds
more water. With RAIM, the offense is "you built it to appeal to
instrument pilots..." We already have culpability in "appealing to
children", this is not much of a stretch.

And the truth is, RAIM is not useful VFR. It adds complexity to the
software and the screen, to no navigational benefit. But it is
essential IFR (or IMC anyway). So the argument above will gain
traction. Food for lawyers. We pay for it.

Jose
--
The price of freedom is... well... freedom.
for Email, make the obvious change in the address.

[Will]

"Dave S" > wrote in message
ink.net...
> How would the use of the GPS be responsible for someone's death?

Cessna lost a famous case that steered it out of general aviation for a few
years and got a one billion dollar judgement because a pilot hit a fence.
How was it Cessna's fault that the pilot hit the fence? Heck if I can
figure that out, but if a case can be made a lawyer would go for the money.


> Now you try to justify its cost/benefit by a hypothetical lawsuit over
> the lack of something that is not mandated, not needed and not justified?

Hold on, and stop changing topics and talking about new issues. There was
never any debate about FAA mandate. The discussion about whether it is
needed or justified is a separate discussion within the thread. Jim made a
comment that the feature I described would double the cost. I was trying
to respond just to that point. I did so by pointing out:

- It won't take more than a man month to simply code the needed algorithms
(and I doubt it would take that).

- There wasn't any proof for the claim in any case.

- To the extent it might control some kinds of liability it might actually
be cost beneficial rather than just incurring some additional labor cost.

--
Will

[Will]

"Jose" > wrote in message
om...
> > There
> > is no proof at all for the claim that some straightforward math
calculations
> > in any GPS software is going to to double the cost of the GPS.
>
> Have you ever written software?

I have managed at least three teams commercially on four projects in the
last 10 years, and at least two of those projects had over 200K lines of
code. So I guess that would be a yes.


> > If it prevents one death that results in a multi-million dollar lawsuit,
it
> > would payback the one man-month of work it might take to do those
> > calculations in software 100 fold or more.
>
> It is actually more likely to =cause= a death - to a pilot who decides
> to rely on a handheld because it has RAIM.

First, the pilot shouldn't be using the handheld in IMC unless he got there
during an unplanned emergency and primary instruments failed. Your
position appears to be that any non-FAA certified tool should be
deliberately crippled in order to make sure that pilots don't cheat and try
to use the instrument during IFR flight or during an emergency flight into
IMC? By that logic, we should just stop all technological development,
because God forbid that someone innovates and makes something that is
actually precise, useful, and more advanced than what is already in the
cockpit?

Once the pilot is in an emergency condition, how do you figure that the
pilot is better off following a GPS trace in complete ignorance of the fact
that it is inaccurate by thousands of feet? Since when is (optional)
knowledge a bad thing?

In any case, if someone deliberately takes an uncertified instrument and
uses it as a primary instrument in IFR, they are violating the rules and I
guess they are responsible for their own bad behavior.

--
Will

[Jose]

> I have managed at least three teams commercially on four projects in the
> last 10 years, and at least two of those projects had over 200K lines of
> code. So I guess that would be a yes.

Bug free?

> First, the pilot shouldn't be using the handheld in IMC unless...

True. But pilots will do things they shouldn't do, and the equipment
maker gets sued, whether they helped cause the crash or not. This is
expensive even if they win.

> Your position appears to be

It's not my position. I am proposing reasons why it isn't done.
Whether is =should= be done is another question, but I can easily see
why they don't do it.

> By that logic, we should just stop all technological development,
> because God forbid that someone innovates and makes something that is
> actually precise, useful, and more advanced than what is already in the
> cockpit?

This is the logic behind a lot of aircraft design. I am not a lawyer,
but I vaguely recall a case against (I think) Cessna which came down to
"this design is bad and caused the crash. You knew it was bad because
twenty years later you improved it". I don't know if Cessna won or
lost, but the idea had traction.

> In any case, if someone deliberately takes an uncertified instrument and
> uses it as a primary instrument in IFR, they are violating the rules and I
> guess they are responsible for their own bad behavior.

Well, the pilot does an SPT and kills somebody on the ground, who sues
the pilot, the plane maker, the GPS maker, the airport where the plane
took off from, and the stars in the sky. It comes down to who has more
money from which to collect. If the pilot and his insurance is
significantly less than the GPS maker and his insurance, then any sane
lawyer will go after the GPS maker. The argument that the GPS maker
enticed the pilot to use this device in IMC will likely gain traction
against a judge and/or jury of non-pilots who see many other cases of
enticement for profit.

It =is= the pilot's fault. But the victim is dead and the GPS maker has
more money. I wouldn't blame the GPS maker for being gun-shy about
putting in a feature of less than dubious value in the face of this.

I wish it were different.

Jose
--
The price of freedom is... well... freedom.
for Email, make the obvious change in the address.

[Sam Spade]

Will wrote:
>
>
> Hold on, and stop changing topics and talking about new issues. There was
> never any debate about FAA mandate. The discussion about whether it is
> needed or justified is a separate discussion within the thread. Jim made a
> comment that the feature I described would double the cost. I was trying
> to respond just to that point. I did so by pointing out:
>
> - It won't take more than a man month to simply code the needed algorithms
> (and I doubt it would take that).

If you have an avionics engineering background, you should know that
TSO-C129 is not only enabling, it is specific and fairly limiting. The
avionics vendors are constrained by the TSO. The TSO serves a purpose,
to permit an IFR platfrom for GPS terminal and approach operations
within a National Airspace System that has yet to be declared
GPS-primary, much less sole source.

I am very familiar with the Garmin 530. I have also owned three Garmin
aviation handheld units, the 195, 295, and 296. The handhelds have had
progressively sophisticated features that the Garmin 530 does not have
because the 530 had to go through a very extensive certification process
to be qualified for IFR operations. Not so with the handhelds.

Garmin has millions tied up in both their IFR and VFR programs. They
seem to be progressing along quite nicely in providing products
appropriate for the operation.

I have my own ways of independendly verifying the accuracy of my 296 by
using DME at the appropriate time. That provides a great accuracy
check, which is valid for a limited period of time. But, it is hardly
approach RAIM. Also, the TSO-C129 sets actually increase accuracy as
well as assure a high level of integrity in the final approach segment
using approach RAIM.

As I said previously, and you chose to ignore, you seem to be looking
for a full press RNP platform, which would not only have redundant
alerting and actual navigation performance (ANP) it is not limited to
the three levels of sensitivity that TSO C129 constrains; en route,
terminal, and approach. (BTW your handheld does not meet those
sensitivity requirements, either).

A Boeing 727-NG, which is available is a business jet version, has
everything you are looking for, including three IRUs that are constantly
updated by GPS and have position blending. Then, in the event of a
failue of GPS (typically local jamming) the IRUs will continue to
provide very low numbers of RNP accuracy, integrity, and continuity.

I think you might be in over your head a tad and, in the process,
digging a hole for yourself for no good reason. ;-)

[Sam Spade]

Roy Smith wrote:

> In article >,
> Jose > wrote:
>
>
>>It is actually more likely to =cause= a death - to a pilot who decides
>>to rely on a handheld because it has RAIM.
>>
>>Jose
>
>
> And tell me that pilots aren't already using those "for situational
> awareness only" extended runway centerlines drawn on the moving maps of
> VFR-only handhelds to cobble up their own instrument approaches?

You can't design the system to account for cheaters.

[Sam Spade]

Will wrote:

>
> Once the pilot is in an emergency condition, how do you figure that the
> pilot is better off following a GPS trace in complete ignorance of the fact
> that it is inaccurate by thousands of feet? Since when is (optional)
> knowledge a bad thing?

With a properly mounted attenna and a check of satellite geometry, that
simply is not going to happen with a good handheld, such as the Garmin
296/396.

I have hundreds of hours using the 195/295/296 in aviation, automotive,
and marine modes and have never, ever seen significant degragation of
accuracy when the antenna has a good view of the sky.

I have seen very poor solutions, however, when using it through a cabin
window of an airliner. I have also seen very good accuracy in that
circumstance, depending upon available satellite geometry.

Finally, as I said before, an accuracy check with DME in a light
aircraft can provide a great, short term, accuracy and integrity check
for a handheld, albeit now as good as approach RAIM.

Also, the later Garmin 500 series as fault detection exclusion, which
makes them certified for sole-source oceanic IFR. Were you aware of that?

[Sam Spade]

J. Severyn wrote:

> Well you get a real-time calculated number in the horizontal direction,
>
> http://www.garmin.com/manuals/GNS430_PilotsGuide.pdf pages 44, 46
> and
> http://www.garmin.com/manuals/GNS530_PilotsGuide.pdf page 43
>
> Garmin calculates the Estimated Position Error (in feet or meters
> horizontally), but does not present an estimate of the vertical error. I
> believe Garmin has done this on most if not all of their aviation units,
> handheld and panel mount. I've got an old GPS95XL and it does the same
> thing.

The vertical solution is not part of the IFR certification of an IFR
unit under TSOC-129. It simply is not good enough for IFR.

IFR-certified Baro VNAV and LPV are the only valid vertical solutions to
date.

[Dave Butler]

> What I was
> describing doesn't require any new hardware, and it's just a matter of
> calculating some accuracy numbers and representing them in the standard UI.

Hee hee. Those of us who develop software have all heard this one before. "It's
a simple matter of programming..."

Har har

[Thomas Borchert]

Will,

> I assumed as much, which is why I wanted to know how that condition is
> displayed on the Garmin 430/530.
>

The airplane symbol changes (color? blinking? I forgot - the manual is
available online at garmin.com), should the number of satellites fall
below the required level. However, in opposition to your situation, the
antenna is outside the airplane on its top, so it is very unlikely to
have that situation. Also, the receiver uses not only RAIM, but RAIM
prediction for the route programmed into it, so it will analyze the
satellite constellation in advance and alert of problems. If RAIM isn't
sufficient, you'll get a warning and will have to use a different
approach.

All this is part of what makes the units "approach certified". Thus, a
pilot doesn't need to worry about PDOP values or some such, the box will
simply say GO or NO GO.

--
Thomas Borchert (EDDH)

[Thomas Borchert]

Will,

> I want the GPS to take all of the inputs for number of satellites and signal
> strength and derive from that just two integers:
>

What you want is in the values for PDOP, VDOP and HDOP - and EPE.

--
Thomas Borchert (EDDH)

[Thomas Borchert]

Will,

> Specifically I want to know the number of feet/meters of
> accuracy of my current position, that's all. If my current accuracy is 10
> ft vertical versus 100 ft vertical versus 1000 ft vertical, that means
> something to me about how much trust I should put in the GPS display.
>

Again, for a pilot, that's not useful information. It might be nice to know,
but for a pilot, useful is only if the GPS works or not - to specifications
set by the FAA during certification.

--
Thomas Borchert (EDDH)

[Thomas Borchert]

Will,

> * It helps to educate me about GPS and conditions in my immediate
> surroundings that might affect accuracy of the technology.
>
> * It helps to alert me about possibly deteriorating conditions, before I get
> into a situation where I needed to rely on the instrument and suddenly I
> cannot.
>

Are you a pilot? Instrument rated? Trust the people here that are: During an
approach you have other things to worry about.

--
Thomas Borchert (EDDH)

[Thomas Borchert]

Will,

> Knowing the exact number of
> meters of accuracy is for my taste a critical piece of information.
>

Why? The distance to obstacles during approach is designed to be
sufficient for the worst case allowed under certification. If the
signal quality doesn't meet those criteria, the receiver will tell you.
Why should you need to know more?

--
Thomas Borchert (EDDH)

[Thomas Borchert]

Will,

> There
> is no proof at all for the claim that some straightforward math calculations
> in any GPS software is going to to double the cost of the GPS.
>

Again, the info you seek is in the values EPE, PDOP, VDOP and HDOP, which most
GPS receivers readily display. It's just not exactly the format you propose.
Who cares?

--
Thomas Borchert (EDDH)

[Thomas Borchert]

Roy,

> And tell me that pilots aren't already using those "for situational
> awareness only" extended runway centerlines drawn on the moving maps of
> VFR-only handhelds to cobble up their own instrument approaches?
>

If they do, and they come to harm - their problem.

--
Thomas Borchert (EDDH)

[Thomas Borchert]

Will,

> First, the pilot shouldn't be using the handheld in IMC
>

Wrong. In fact, completely wrong. It just shouldn't be his primary nav
source.

--
Thomas Borchert (EDDH)

[Sam Spade]

Thomas Borchert wrote:

> Will,
>
>
>>First, the pilot shouldn't be using the handheld in IMC
>>
>
>
> Wrong. In fact, completely wrong. It just shouldn't be his primary nav
> source.
>
A Garmin 296 or 396 can be used as secondary to an IFR-certified GPS
simply as a "poor man's TAWS. Those sets are quite good in that reqard.

[Ron Lee]

Will, I could not add the Estimated Position Error to the main display
map. Frankly, that is useless for deterrmining the validity
(integrity) of the signal. It is based upon assumed system errors and
satellite positions (DOP- Dilution of Precision).

RAIM (seen in the lower left corner of the 430, actually chesks the
signal solutions for integrity.

If you are really worried about the DOP/EPE, switch to the satellite
status page which shows satellite az/el and signal "strength" along
with DOP and EPE.

Ron Lee

[karl gruber]

"Will" > First, the pilot shouldn't be using the handheld in IMC



Why not?

Curator N185KG

[Ron Lee]

"karl gruber" > wrote:

>"Will" > First, the pilot shouldn't be using the handheld in IMC
>
>Why not?

Of course he can for situational awareness. But not for primary
navigation info.

Ron Lee

[Steven P. McNicoll]

"Ron Lee" > wrote in message
...
> "karl gruber" > wrote:
>
>>"Will" > First, the pilot shouldn't be using the handheld in IMC
>>
>>Why not?
>
> Of course he can for situational awareness. But not for primary
> navigation info.
>

Why not?

[Steven P. McNicoll]

"Will" > wrote in message
...
>
> First, the pilot shouldn't be using the handheld in IMC unless he got
> there
> during an unplanned emergency and primary instruments failed.
>

Why not?

[Steven P. McNicoll]

"Thomas Borchert" > wrote in message
...
> Will,
>
>> First, the pilot shouldn't be using the handheld in IMC
>>
>
> Wrong. In fact, completely wrong. It just shouldn't be his primary nav
> source.
>

Why shouldn't it be his primary nav source?

[Bob Noel]

In article et>,
"Steven P. McNicoll" > wrote:

> Why shouldn't it be his primary nav source?

google is your friend.

--
Bob Noel
Looking for a sig the
lawyers will hate

[Steven P. McNicoll]

"Bob Noel" > wrote in message
...
> In article et>,
> "Steven P. McNicoll" > wrote:
>
>> Why shouldn't it be his primary nav source?
>
> google is your friend.
>

This question has Google stumped.

[[email protected]]

to the original question, I would note that my 396 displays "accuracy"
of the gps solution by drawing an "uncertainty" circle around the
airplane. You can also display the error in ft.


k

[Will]

That is a great user interface for showing accuracy on an ongoing basis.
Do you know what technology they use to make that circle calculation?

How do you turn on that feature? Maybe it is in the 430/530 as well?

--
Will


> wrote in message
oups.com...
> to the original question, I would note that my 396 displays "accuracy"
> of the gps solution by drawing an "uncertainty" circle around the
> airplane. You can also display the error in ft.
>
>
> k
>

[Thomas Borchert]

Steven,

> Why shouldn't it be his primary nav source?
>

Because it is a handheld, which is not approved for IFR use, enroute or
approach.

--
Thomas Borchert (EDDH)

[Ted]

"Steven P. McNicoll" > wrote in message
ink.net...
>
> "Bob Noel" > wrote in message
> ...
>> In article et>,
>> "Steven P. McNicoll" > wrote:
>>
>>> Why shouldn't it be his primary nav source?
>>
>> google is your friend.
>>
>
> This question has Google stumped.
>

Perhaps google is only Bob's special friend.

[Bob Noel]

In article et>,
"Ted" > wrote:

> "Steven P. McNicoll" > wrote in message
> ink.net...
> >
> > "Bob Noel" > wrote in message
> > ...
> >> In article et>,
> >> "Steven P. McNicoll" > wrote:
> >>
> >>> Why shouldn't it be his primary nav source?
> >>
> >> google is your friend.
> >>
> >
> > This question has Google stumped.
> >
>
> Perhaps google is only Bob's special friend.

or perhaps Steven doesn't remember asking this question over and over
and over and over and over....

--
Bob Noel
Looking for a sig the
lawyers will hate

[Steven P. McNicoll]

"Thomas Borchert" > wrote in message
...
>
> Because it is a handheld, which is not approved for IFR use, enroute or
> approach.
>

No approval is required for enroute use of a handheld GPS in the US.

[Steven P. McNicoll]

"Bob Noel" > wrote in message
...
>
> or perhaps Steven doesn't remember asking this question over and over
> and over and over and over....
>

Steven does remember that. He also remembers that nobody has ever answered
the question correctly.

[Bob Noel]

In article . net>,
"Steven P. McNicoll" > wrote:

> > or perhaps Steven doesn't remember asking this question over and over
> > and over and over and over....
>
> Steven does remember that. He also remembers that nobody has ever answered
> the question correctly.

yeah, right.

--
Bob Noel
Looking for a sig the
lawyers will hate

[Bob Noel]

In article . net>,
"Steven P. McNicoll" > wrote:

> "Thomas Borchert" > wrote in message
> ...
> >
> > Because it is a handheld, which is not approved for IFR use, enroute or
> > approach.
> >
>
> No approval is required for enroute use of a handheld GPS in the US.

where is "enroute use" defined?

--
Bob Noel
Looking for a sig the
lawyers will hate

[Sam Spade]

Will wrote:
> That is a great user interface for showing accuracy on an ongoing basis.
> Do you know what technology they use to make that circle calculation?
>
> How do you turn on that feature? Maybe it is in the 430/530 as well?
>

Garmin can do what it chooses with its VFR units. The IFR units are
subject to TSO-C129 (or 146 for LPV).

Again, as I have said here a couple of times, the stuff you are looking
for appears on a full-press RNP platform where, because of very tight
containment areas, such "belts and suspenders" become critically important.

It just doesn't matter in the relatively large amount of airspace
provided for TSO-C129 instrument approach procedures.

I work with this stuff professionally almost every day. And, I have a
whole lot of flying time and couldn't care less about what concerns you
when I am flying behind a Garmin 530.

I have my hands full enough with a 530 doing what I am supposed to be
doing, such as verifying the legs of an instrument approach before I
possibly get led astray by a faulty database. Do you do that for each
and every IAP?

My first exposure to RNAV was in an early 767 with airway database, CDU
entry, etc, etc. The Garmin 400/500 series is much more difficult to
truely master than a full FMS LNAV platform. I am not a hobbiest, yet I
am learning something new about the 530 all the time.

One of these days, I may have the opportunity to learn the
state-of-the-art FMS LNAV RNP platform on the 737-NG. Then, and only
then, will I become concerned about actual navigation performance (ANP).

[Steven P. McNicoll]

"Bob Noel" > wrote in message
...
>
> where is "enroute use" defined?
>

Dictionary

[Sam Spade]

Steven P. McNicoll wrote:

> "Thomas Borchert" > wrote in message
> ...
>
>>Because it is a handheld, which is not approved for IFR use, enroute or
>>approach.
>>
>
>
> No approval is required for enroute use of a handheld GPS in the US.
>
>
Handhelds are prohibited by the FAA for use in Part 121 and 135
operations with some special exceptions (require a special authorization).

Because non-commercial operators do not have ops specs that spell this
stuff out doesn't mean that primary nav equipment doesn't have to be
approved for IFR. Fact is, it does.

A handheld it simply not a piece of IFR-certified avionics, no matter
Part 91-only, or 121/135, etc.

Can a Part 91-only pilot use a hand-held to augment IFR navigation? Of
course he can. But, even then, he can run afoul of some FSDO folks if
the handheld is "installed" and used to augment IFR navigation. That
depends on the inclinations of the particular FSDO.

[Thomas Borchert]

Steven,

> No approval is required for enroute use of a handheld GPS in the US.
>

Hmm. I remember differently. How do you explain GPS IFR enroute
certification, which is available for some panel-mounts?

--
Thomas Borchert (EDDH)

[Steven P. McNicoll]

"Sam Spade" > wrote in message
news:Ho44g.174356$bm6.111656@fed1read04...
>
> Handhelds are prohibited by the FAA for use in Part 121 and 135 operations
> with some special exceptions (require a special authorization).
>

But they are not prohibited for use in Part 91 operations.


>
> Because non-commercial operators do not have ops specs that spell this
> stuff out doesn't mean that primary nav equipment doesn't have to be
> approved for IFR. Fact is, it does.
>

What requires that it be approved?


>
> A handheld it simply not a piece of IFR-certified avionics, no matter Part
> 91-only, or 121/135, etc.
>

So what?


>
> Can a Part 91-only pilot use a hand-held to augment IFR navigation? Of
> course he can. But, even then, he can run afoul of some FSDO folks if the
> handheld is "installed" and used to augment IFR navigation. That depends
> on the inclinations of the particular FSDO.
>

Handhelds are not "installed". Running afoul of some FSDO folks is a
non-issue. Their personal biases are irrelevant, what matters is what is in
the regulations.

[Steven P. McNicoll]

"Thomas Borchert" > wrote in message
...
>
> Hmm. I remember differently.
>

So what do you remember?


>
> How do you explain GPS IFR enroute
> certification, which is available for some panel-mounts?
>

I assume you're referring to TSO C-129a. It exists, but it's mere existence
does not prohibit the use of equipment that hasn't been demonstrated to meet
the standard.

TSOs are not regulations, they are Technical Standard Orders. TSOs are not
binding unless there is an FAR that requires the TSO to be complied with, so
says FAR 21.601. There are TSOs in existence that cover the "approval" of a
great many things, but you don't have to use "approved" equipment in any
operation unless required to do so by the FARs. What FAR requires
compliance with TSO-C129a?


PART 21--CERTIFICATION PROCEDURES FOR PRODUCTS AND PARTS


Subpart O--Technical Standard Order Authorizations


Sec. 21.601 Applicability.


[snip]


(b) For the purpose of this subpart--


[snip]


(4) An article manufactured under a TSO authorization, an FAA letter of
acceptance as described in §21.603(b), or an appliance manufactured under a
letter of TSO design approval described in §21.617 is an approved article or
appliance for the purpose of meeting the regulations of this chapter that
require the article to be approved.

[Sam Spade]

Steven P. McNicoll wrote:
> "Sam Spade" > wrote in message
> news:Ho44g.174356$bm6.111656@fed1read04...
>
>>Handhelds are prohibited by the FAA for use in Part 121 and 135 operations
>>with some special exceptions (require a special authorization).
>>
>
>
> But they are not prohibited for use in Part 91 operations.

They are as primary nav for IFR.
>
>
>
>>Because non-commercial operators do not have ops specs that spell this
>>stuff out doesn't mean that primary nav equipment doesn't have to be
>>approved for IFR. Fact is, it does.
>>
>
>
> What requires that it be approved?

Part 23 (for the type of aircraft we're talking about). A good avionics
shop can direct you to related ACs.
>
>
>
>>A handheld it simply not a piece of IFR-certified avionics, no matter Part
>>91-only, or 121/135, etc.
>>
>
>
> So what?

So, it does not satisfy Part 23, which requires that the avionics
manufacturer provide equipment (in this case) that is appropriate for
IFR operations.
>
>
>
>>Can a Part 91-only pilot use a hand-held to augment IFR navigation? Of
>>course he can. But, even then, he can run afoul of some FSDO folks if the
>>handheld is "installed" and used to augment IFR navigation. That depends
>>on the inclinations of the particular FSDO.
>>
>
>
> Handhelds are not "installed". Running afoul of some FSDO folks is a
> non-issue. Their personal biases are irrelevant, what matters is what is in
> the regulations.

Handhelds are typically not installed. But, once they are connected to
an external antenna and/or ship's power supply they are usually
considered to be installed.
>

[Sam Spade]

Also, AIM 1-1-19:

d. General Requirements
1. Authorization to conduct any GPS operation under IFR requires that:

(a) GPS navigation equipment used must be approved in accordance with
the requirements specified in Technical Standard Order (TSO) TSO-C129,
or equivalent, and the installation must be done in accordance with
Advisory Circular AC 20-138, Airworthiness Approval of Global
Positioning System (GPS) Navigation Equipment for Use as a VFR and IFR
Supplemental Navigation System, or Advisory Circular AC 20-130A,
Airworthiness Approval of Navigation or Flight Management Systems
Integrating Multiple Navigation Sensors, or equivalent. Equipment
approved in accordance with TSO-C115a does not meet the requirements of
TSO-C129. Visual flight rules (VFR) and hand-held GPS systems are not
authorized for IFR navigation, instrument approaches, or as a principal
instrument flight reference. During IFR operations they may be
considered only an aid to situational awareness.

(b) Aircraft using GPS navigation equipment under IFR must be equipped
with an approved and operational alternate means of navigation
appropriate to the flight. Active monitoring of alternative navigation
equipment is not required if the GPS receiver uses RAIM for integrity
monitoring. Active monitoring of an alternate means of navigation is
required when the RAIM capability of the GPS equipment is lost.

(c) Procedures must be established for use in the event that the loss of
RAIM capability is predicted to occur. In situations where this is
encountered, the flight must rely on other approved equipment, delay
departure, or cancel the flight.

(d) The GPS operation must be conducted in accordance with the
FAA-approved aircraft flight manual (AFM) or flight manual supplement.
Flight crew members must be thoroughly familiar with the particular GPS
equipment installed in the aircraft, the receiver operation manual, and
the AFM or flight manual supplement. Unlike ILS and VOR, the basic
operation, receiver presentation to the pilot, and some capabilities of
the equipment can vary greatly. Due to these differences, operation of
different brands, or even models of the same brand, of GPS receiver
under IFR should not be attempted without thorough study of the
operation of that particular receiver and installation. Most receivers
have a built-in simulator mode which will allow the pilot to become
familiar with operation prior to attempting operation in the aircraft.
Using the equipment in flight under VFR conditions prior to attempting
IFR operation will allow further familiarization.

(e) Aircraft navigating by IFR approved GPS are considered to be area
navigation (RNAV) aircraft and have special equipment suffixes. File the
appropriate equipment suffix in accordance with TBL 5-1-2, on the ATC
flight plan. If GPS avionics become inoperative, the pilot should advise
ATC and amend the equipment suffix.

(f) Prior to any GPS IFR operation, the pilot must review appropriate
NOTAMs and aeronautical information. (See GPS NOTAMs/Aeronautical
Information.)

(g) Air carrier and commercial operators must meet the appropriate
provisions of their approved operations specifications.

[John R. Copeland]

"Sam Spade" > wrote in message news:0984g.174363$bm6.171092@fed1read04...
>
> Also, AIM 1-1-19:
>
> d. General Requirements
> 1. Authorization to conduct any GPS operation under IFR requires that:
>
> (a) GPS navigation equipment used must be approved in accordance with
> the requirements specified in Technical Standard Order (TSO) TSO-C129,
> or equivalent, and the installation must be done in accordance with
> Advisory Circular AC 20-138, Airworthiness Approval of Global
> Positioning System (GPS) Navigation Equipment for Use as a VFR and IFR
> Supplemental Navigation System, or Advisory Circular AC 20-130A,
> Airworthiness Approval of Navigation or Flight Management Systems
> Integrating Multiple Navigation Sensors, or equivalent. Equipment
> approved in accordance with TSO-C115a does not meet the requirements of
> TSO-C129. Visual flight rules (VFR) and hand-held GPS systems are not
> authorized for IFR navigation, instrument approaches, or as a principal
> instrument flight reference. During IFR operations they may be
> considered only an aid to situational awareness.
>
> <snip>
>

If that's *the* defining statement, then I must not be authorized to operate
under IFR with my equipment which is certified under TSO-C146a,
Stand-Alone Airborne Navigation Equipment using the Global Positioning
System (GPS) Augmented by the Wide Area Augmentation System (WAAS).
But I think I am so authorized.
Must we say once again that the AIM is not regulatory?

[ted]

"Steven P. McNicoll" > wrote in message
ink.net...
>
> "Bob Noel" > wrote in message
> ...
>>
>> where is "enroute use" defined?
>>
>
> Dictionary
>

Oh, Steven!!!

You had the PERFECT chance to reply: "Google is your friend"

but you didn't take it. Rats.

[Sam Spade]

John R. Copeland wrote:

> "Sam Spade" > wrote in message news:0984g.174363$bm6.171092@fed1read04...
>
>>Also, AIM 1-1-19:
>>
>>d. General Requirements
>>1. Authorization to conduct any GPS operation under IFR requires that:
>>
>>(a) GPS navigation equipment used must be approved in accordance with
>>the requirements specified in Technical Standard Order (TSO) TSO-C129,
>>or equivalent, and the installation must be done in accordance with
>>Advisory Circular AC 20-138, Airworthiness Approval of Global
>>Positioning System (GPS) Navigation Equipment for Use as a VFR and IFR
>>Supplemental Navigation System, or Advisory Circular AC 20-130A,
>>Airworthiness Approval of Navigation or Flight Management Systems
>>Integrating Multiple Navigation Sensors, or equivalent. Equipment
>>approved in accordance with TSO-C115a does not meet the requirements of
>>TSO-C129. Visual flight rules (VFR) and hand-held GPS systems are not
>>authorized for IFR navigation, instrument approaches, or as a principal
>>instrument flight reference. During IFR operations they may be
>>considered only an aid to situational awareness.
>>
>> <snip>
>>
>
> If that's *the* defining statement, then I must not be authorized to operate
> under IFR with my equipment which is certified under TSO-C146a,
> Stand-Alone Airborne Navigation Equipment using the Global Positioning
> System (GPS) Augmented by the Wide Area Augmentation System (WAAS).
> But I think I am so authorized.
> Must we say once again that the AIM is not regulatory?
>
I suppose your 146 equipment is "equivalent."

Keep in mind the FAA does not do a perfect job of keeping the AIM
current. And, of course, it is not regulatory, but it is sometimes
directive and a focal point to provide information to pilots.

The regulatory vehicle for your installation is via the approved
installation process a la Part 23.

[Bob Noel]

In article et>,
"Steven P. McNicoll" > wrote:

> > where is "enroute use" defined?
>
> Dictionary

yeah. that's good. Is that where you get your definition
of "night", "pilot-in-command", etc?

--
Bob Noel
Looking for a sig the
lawyers will hate

[Greg Farris]

In article >,
says...

>I just don't understand the issue about pilot overload. I'm asking for two
>integers, and you don't need to look at them ever if you don't want to.
>

Will, I think you should look at this picture :

http://www.airliners.net/open.file?id=0286741


Then write back and tell us you really think we need some more numbers there,
to give us redundant information. The 430's in the picture already have RAIM,
and will warn the pilot if the information is below standard - Does this guy
look like he's starved for more numbers to stare at?

GF

[Sam Spade]

Greg Farris wrote:

>
> Then write back and tell us you really think we need some more numbers there,
> to give us redundant information. The 430's in the picture already have RAIM,
> and will warn the pilot if the information is below standard - Does this guy
> look like he's starved for more numbers to stare at?
>
> GF
>
I suspect he too busy worrying about what to do it an engine fails in
that underpowered twin.

[Thomas Borchert]

Steven,

You know, with all due respect, your "discussion style" is really weird
(annoying, too, if I may say so). How about giving answers instead of
only asking questions? If you think you know something, tell us instead
of smart-*ssing the group to death.

--
Thomas Borchert (EDDH)

[Greg Farris]

In article <Ato4g.174429$bm6.92343@fed1read04>, says...

>I suspect he too busy worrying about what to do it an engine fails in
>that underpowered twin.




I'll let Mike Rappoport field that one, if he's with us!!

[Steven P. McNicoll]

"Sam Spade" > wrote in message
news:Kt74g.174361$bm6.134909@fed1read04...
>
> They are as primary nav for IFR.
>

Cite the applicable regulation.


>
> Part 23 (for the type of aircraft we're talking about). A good avionics
> shop can direct you to related ACs.
>

We're not talking about a type of aircraft, we're talking about use of
handheld GPS. Part 23 is not applicable.


>
> So, it does not satisfy Part 23, which requires that the avionics
> manufacturer provide equipment (in this case) that is appropriate for IFR
> operations.
>

Part 23 prescribes airworthiness standards for the issue of type
certificates, and changes to those certificates, for airplanes in the
normal, utility, acrobatic, and commuter categories. It has nothing to do
with uninstalled devices such as handheld GPS.

You can examine Part 23 here: http://makeashorterlink.com/?D2FD2580D


>
> Handhelds are typically not installed. But, once they are connected to an
> external antenna and/or ship's power supply they are usually considered to
> be installed.
>

Only by the irrational.

[Steven P. McNicoll]

"Sam Spade" > wrote in message
news:0984g.174363$bm6.171092@fed1read04...
>
> Also, AIM 1-1-19:
>
> d. General Requirements
> 1. Authorization to conduct any GPS operation under IFR requires that:
>
> (a) GPS navigation equipment used must be approved in accordance with the
> requirements specified in Technical Standard Order (TSO) TSO-C129, or
> equivalent, and the installation must be done in accordance with Advisory
> Circular AC 20-138, Airworthiness Approval of Global Positioning System
> (GPS) Navigation Equipment for Use as a VFR and IFR Supplemental
> Navigation System, or Advisory Circular AC 20-130A, Airworthiness Approval
> of Navigation or Flight Management Systems Integrating Multiple Navigation
> Sensors, or equivalent. Equipment approved in accordance with TSO-C115a
> does not meet the requirements of TSO-C129. Visual flight rules (VFR) and
> hand-held GPS systems are not authorized for IFR navigation, instrument
> approaches, or as a principal instrument flight reference. During IFR
> operations they may be considered only an aid to situational awareness.
>
> (b) Aircraft using GPS navigation equipment under IFR must be equipped
> with an approved and operational alternate means of navigation appropriate
> to the flight. Active monitoring of alternative navigation equipment is
> not required if the GPS receiver uses RAIM for integrity monitoring.
> Active monitoring of an alternate means of navigation is required when the
> RAIM capability of the GPS equipment is lost.
>
> (c) Procedures must be established for use in the event that the loss of
> RAIM capability is predicted to occur. In situations where this is
> encountered, the flight must rely on other approved equipment, delay
> departure, or cancel the flight.
>
> (d) The GPS operation must be conducted in accordance with the
> FAA-approved aircraft flight manual (AFM) or flight manual supplement.
> Flight crew members must be thoroughly familiar with the particular GPS
> equipment installed in the aircraft, the receiver operation manual, and
> the AFM or flight manual supplement. Unlike ILS and VOR, the basic
> operation, receiver presentation to the pilot, and some capabilities of
> the equipment can vary greatly. Due to these differences, operation of
> different brands, or even models of the same brand, of GPS receiver under
> IFR should not be attempted without thorough study of the operation of
> that particular receiver and installation. Most receivers have a built-in
> simulator mode which will allow the pilot to become familiar with
> operation prior to attempting operation in the aircraft. Using the
> equipment in flight under VFR conditions prior to attempting IFR operation
> will allow further familiarization.
>
> (e) Aircraft navigating by IFR approved GPS are considered to be area
> navigation (RNAV) aircraft and have special equipment suffixes. File the
> appropriate equipment suffix in accordance with TBL 5-1-2, on the ATC
> flight plan. If GPS avionics become inoperative, the pilot should advise
> ATC and amend the equipment suffix.
>
> (f) Prior to any GPS IFR operation, the pilot must review appropriate
> NOTAMs and aeronautical information. (See GPS NOTAMs/Aeronautical
> Information.)
>
> (g) Air carrier and commercial operators must meet the appropriate
> provisions of their approved operations specifications.
>


AIM Preface, see subparagraph d.:


Flight Information Publication Policy



The following is in essence, the statement issued by the FAA
Administrator and published in the December 10, 1964, issue of the Federal
Register, concerning the FAA policy as pertaining to the type of information
that will be published as NOTAMs and in the Aeronautical Information Manual.

a. It is a pilot's inherent responsibility to be alert at all times
for and in anticipation of all circumstances, situations, and conditions
affecting the safe operation of the aircraft. For example, a pilot should
expect to find air traffic at any time or place. At or near both civil and
military airports and in the vicinity of known training areas, a pilot
should expect concentrated air traffic and realize concentrations of air
traffic are not limited to these places.

b. It is the general practice of the agency to advertise by NOTAM or
other flight information publications such information it may deem
appropriate; information which the agency may from time to time make
available to pilots is solely for the purpose of assisting them in executing
their regulatory responsibilities. Such information serves the aviation
community as a whole and not pilots individually.

c. The fact that the agency under one particular situation or another
may or may not furnish information does not serve as a precedent of the
agency's responsibility to the aviation community; neither does it give
assurance that other information of the same or similar nature will be
advertised, nor, does it guarantee that any and all information known to the
agency will be advertised.

d. This publication, while not regulatory, provides information which
reflects examples of operating techniques and procedures which may be
requirements in other federal publications or regulations. It is made
available solely to assist pilots in executing their responsibilities
required by other publications.

Consistent with the foregoing, it shall be the policy of the Federal
Aviation Administration to furnish information only when, in the opinion of
the agency, a unique situation should be advertised and not to furnish
routine information such as concentrations of air traffic, either civil or
military. The Aeronautical Information Manual will not contain informative
items concerning everyday circumstances that pilots should, either by good
practices or regulation, expect to encounter or avoid.

[Steven P. McNicoll]

"John R. Copeland" > wrote in message
.. .
>
> Must we say once again that the AIM is not regulatory?
>

I doubt it would do any good.

[Steven P. McNicoll]

"Sam Spade" > wrote in message
news:ZK94g.174370$bm6.21952@fed1read04...
>
> Keep in mind the FAA does not do a perfect job of keeping the AIM current.
> And, of course, it is not regulatory, but it is sometimes directive and a
> focal point to provide information to pilots.
>

If you knew the AIM was not regulatory why did you cite AIM para 1-1-19?

[Steven P. McNicoll]

"ted" > wrote in message
ink.net...
>
> Oh, Steven!!!
>
> You had the PERFECT chance to reply: "Google is your friend"
>
> but you didn't take it. Rats.
>

Because Google is not Bob's friend!

[Steven P. McNicoll]

"Bob Noel" > wrote in message
...
>
> yeah. that's good. Is that where you get your definition
> of "night", "pilot-in-command", etc?
>

The dictionary has fine definitions of those words.

[Steven P. McNicoll]

"Thomas Borchert" > wrote in message
...
>
>Steven,
>
> You know, with all due respect, your "discussion style" is really weird
> (annoying, too, if I may say so).
>

What do you find weird about it? In what way do you find it annoying?


>
> How about giving answers instead of only asking questions?
>

What questions would you like me to answer?



>
> If you think you know something, tell us instead
> of smart-*ssing the group to death.
>

Haven't I done that? Didn't I tell you that no approval is required for
enroute use of a handheld GPS in the US? Didn't I tell you that the mere
existence of a TSO does not prohibit the use of equipment that hasn't been
demonstrated to meet the standard? Didn't I tell you TSOs are not binding
unless there is an FAR that requires the TSO to be complied with? Didn't I
tell you there are TSOs in existence that cover the "approval" of a great
many things, but you don't have to use "approved" equipment in any operation
unless required to do so by the FARs? Isn't telling you those things
telling you something?

[Sam Spade]

Steven P. McNicoll wrote:
> "Sam Spade" > wrote in message
> news:Kt74g.174361$bm6.134909@fed1read04...
>
>>They are as primary nav for IFR.
>>
>
>
> Cite the applicable regulation.
>
>
>
>>Part 23 (for the type of aircraft we're talking about). A good avionics
>>shop can direct you to related ACs.
>>
>
>
> We're not talking about a type of aircraft, we're talking about use of
> handheld GPS. Part 23 is not applicable.
>
>
>
>>So, it does not satisfy Part 23, which requires that the avionics
>>manufacturer provide equipment (in this case) that is appropriate for IFR
>>operations.
>>
>
>
> Part 23 prescribes airworthiness standards for the issue of type
> certificates, and changes to those certificates, for airplanes in the
> normal, utility, acrobatic, and commuter categories. It has nothing to do
> with uninstalled devices such as handheld GPS.
>
> You can examine Part 23 here: http://makeashorterlink.com/?D2FD2580D
>
>
>
>>Handhelds are typically not installed. But, once they are connected to an
>>external antenna and/or ship's power supply they are usually considered to
>>be installed.
>>
>
>
> Only by the irrational.
>
>
In your view of the world, lots of FSDO inspectors are irrational. I
won't go into the view that FSDO inspectors have of ATC personnel.

As to all the point/counterpoint about handhelds and Part 23, we agree
that a "non-installed" handheld is not subject to any provision of Part
23. What you fail to understand is that, unless a particular item of
avionics that is to be used for primary IFR navigation is so certified,
it cannot be used for primary IFR navigation. Further, if it is
certified for primary IFR navigation, it then has to be installed in
compliance with Part 23. A handheld doesn't quite make the program.

And, please, don't tell me to prove it. Your resource is any G/A
maintenance inspector at your local, friendly FAA FSDO.

[Sam Spade]

Steven P. McNicoll wrote:

> "Sam Spade" > wrote in message
> news:ZK94g.174370$bm6.21952@fed1read04...
>
>>Keep in mind the FAA does not do a perfect job of keeping the AIM current.
>>And, of course, it is not regulatory, but it is sometimes directive and a
>>focal point to provide information to pilots.
>>
>
>
> If you knew the AIM was not regulatory why did you cite AIM para 1-1-19?
>
>
Because it provides guidance to the regulatory requirements. That is
one of the AIMS principal purposes.

Why do you feel I was incorrect in citing directive guidance?

[Sam Spade]

Steven P. McNicoll wrote:

> "Sam Spade" > wrote in message
> news:0984g.174363$bm6.171092@fed1read04...
>
>>Also, AIM 1-1-19:
>>
>>d. General Requirements
>>1. Authorization to conduct any GPS operation under IFR requires that:
>>
>>(a) GPS navigation equipment used must be approved in accordance with the
>>requirements specified in Technical Standard Order (TSO) TSO-C129, or
>>equivalent, and the installation must be done in accordance with Advisory
>>Circular AC 20-138, Airworthiness Approval of Global Positioning System
>>(GPS) Navigation Equipment for Use as a VFR and IFR Supplemental
>>Navigation System, or Advisory Circular AC 20-130A, Airworthiness Approval
>>of Navigation or Flight Management Systems Integrating Multiple Navigation
>>Sensors, or equivalent. Equipment approved in accordance with TSO-C115a
>>does not meet the requirements of TSO-C129. Visual flight rules (VFR) and
>>hand-held GPS systems are not authorized for IFR navigation, instrument
>>approaches, or as a principal instrument flight reference. During IFR
>>operations they may be considered only an aid to situational awareness.
>>
>>(b) Aircraft using GPS navigation equipment under IFR must be equipped
>>with an approved and operational alternate means of navigation appropriate
>>to the flight. Active monitoring of alternative navigation equipment is
>>not required if the GPS receiver uses RAIM for integrity monitoring.
>>Active monitoring of an alternate means of navigation is required when the
>>RAIM capability of the GPS equipment is lost.
>>
>>(c) Procedures must be established for use in the event that the loss of
>>RAIM capability is predicted to occur. In situations where this is
>>encountered, the flight must rely on other approved equipment, delay
>>departure, or cancel the flight.
>>
>>(d) The GPS operation must be conducted in accordance with the
>>FAA-approved aircraft flight manual (AFM) or flight manual supplement.
>>Flight crew members must be thoroughly familiar with the particular GPS
>>equipment installed in the aircraft, the receiver operation manual, and
>>the AFM or flight manual supplement. Unlike ILS and VOR, the basic
>>operation, receiver presentation to the pilot, and some capabilities of
>>the equipment can vary greatly. Due to these differences, operation of
>>different brands, or even models of the same brand, of GPS receiver under
>>IFR should not be attempted without thorough study of the operation of
>>that particular receiver and installation. Most receivers have a built-in
>>simulator mode which will allow the pilot to become familiar with
>>operation prior to attempting operation in the aircraft. Using the
>>equipment in flight under VFR conditions prior to attempting IFR operation
>>will allow further familiarization.
>>
>>(e) Aircraft navigating by IFR approved GPS are considered to be area
>>navigation (RNAV) aircraft and have special equipment suffixes. File the
>>appropriate equipment suffix in accordance with TBL 5-1-2, on the ATC
>>flight plan. If GPS avionics become inoperative, the pilot should advise
>>ATC and amend the equipment suffix.
>>
>>(f) Prior to any GPS IFR operation, the pilot must review appropriate
>>NOTAMs and aeronautical information. (See GPS NOTAMs/Aeronautical
>>Information.)
>>
>>(g) Air carrier and commercial operators must meet the appropriate
>>provisions of their approved operations specifications.
>>
>
>
>
> AIM Preface, see subparagraph d.:
>
>
> Flight Information Publication Policy
>
>
>
> The following is in essence, the statement issued by the FAA
> Administrator and published in the December 10, 1964, issue of the Federal
> Register, concerning the FAA policy as pertaining to the type of information
> that will be published as NOTAMs and in the Aeronautical Information Manual.
>
> a. It is a pilot's inherent responsibility to be alert at all times
> for and in anticipation of all circumstances, situations, and conditions
> affecting the safe operation of the aircraft. For example, a pilot should
> expect to find air traffic at any time or place. At or near both civil and
> military airports and in the vicinity of known training areas, a pilot
> should expect concentrated air traffic and realize concentrations of air
> traffic are not limited to these places.
>
> b. It is the general practice of the agency to advertise by NOTAM or
> other flight information publications such information it may deem
> appropriate; information which the agency may from time to time make
> available to pilots is solely for the purpose of assisting them in executing
> their regulatory responsibilities. Such information serves the aviation
> community as a whole and not pilots individually.
>
> c. The fact that the agency under one particular situation or another
> may or may not furnish information does not serve as a precedent of the
> agency's responsibility to the aviation community; neither does it give
> assurance that other information of the same or similar nature will be
> advertised, nor, does it guarantee that any and all information known to the
> agency will be advertised.
>
> d. This publication, while not regulatory, provides information which
> reflects examples of operating techniques and procedures which may be
> requirements in other federal publications or regulations. It is made
> available solely to assist pilots in executing their responsibilities
> required by other publications.
>
> Consistent with the foregoing, it shall be the policy of the Federal
> Aviation Administration to furnish information only when, in the opinion of
> the agency, a unique situation should be advertised and not to furnish
> routine information such as concentrations of air traffic, either civil or
> military. The Aeronautical Information Manual will not contain informative
> items concerning everyday circumstances that pilots should, either by good
> practices or regulation, expect to encounter or avoid.
>
>
>
And, you point being?

[Sam Spade]

Steven P. McNicoll wrote:

> "Thomas Borchert" > wrote in message
> ...
>
>>Steven,
>>
>>You know, with all due respect, your "discussion style" is really weird
>>(annoying, too, if I may say so).
>>
>
>
> What do you find weird about it? In what way do you find it annoying?
>
>
>
>>How about giving answers instead of only asking questions?
>>
>
>
> What questions would you like me to answer?
>
>
>
>
>>If you think you know something, tell us instead
>>of smart-*ssing the group to death.
>>
>
>
> Haven't I done that? Didn't I tell you that no approval is required for
> enroute use of a handheld GPS in the US? Didn't I tell you that the mere
> existence of a TSO does not prohibit the use of equipment that hasn't been
> demonstrated to meet the standard? Didn't I tell you TSOs are not binding
> unless there is an FAR that requires the TSO to be complied with? Didn't I
> tell you there are TSOs in existence that cover the "approval" of a great
> many things, but you don't have to use "approved" equipment in any operation
> unless required to do so by the FARs? Isn't telling you those things
> telling you something?
>
>
You need to get a better grasp on your employer's policy and
implementation programs. Headquarters has made it abundantly clear that
GPS cannot be used for primary IFR navigation unless the device
complies with TSO 129, 145, or 146 (or is a certified FMS/LNAV
integrated platform). Then, the avionics manufactors of 129, 145, or
146 boxes must prove compliance before they receive certification. And,
then the device has to be installed in an approved manner to satisfy
Part 23.

The AIM material I cited reflects that policy.

[ted]

"Thomas Borchert" > wrote in message
...
> Steven,
>
> You know, with all due respect, your "discussion style" is really weird
> (annoying, too, if I may say so). How about giving answers instead of
> only asking questions? If you think you know something, tell us instead
> of smart-*ssing the group to death.
>
> --
> Thomas Borchert (EDDH)
>

I've been reading Steven's posts for years, Thomas. He only seems to annoy
people who don't know what they are talking about.

[Peter R.]

ted > wrote:

> I've been reading Steven's posts for years, Thomas. He only seems to annoy
> people who don't know what they are talking about.

So, as president of his fan club, could you tell me how to get Steven to
sign my headsets?

--
Peter

[Ted]

"Peter R." > wrote in message
...
> ted > wrote:
>
>> I've been reading Steven's posts for years, Thomas. He only seems to
>> annoy
>> people who don't know what they are talking about.
>
> So, as president of his fan club, could you tell me how to get Steven to
> sign my headsets?
>
> --
> Peter

You misread the post. I'm the president of the fan club of the people who
don't know what they are talking about.

Its a very large club. I'm quite busy keeping up with all the silly things
they say.

[Steven P. McNicoll]

"Sam Spade" > wrote in message
news:1YG4g.174530$bm6.48282@fed1read04...
>
> Because it provides guidance to the regulatory requirements. That is one
> of the AIMS principal purposes.
>

What applicable FAR did AIM 1-1-19 guide you to? Why not then just cite
that FAR, why cite the middle man?


>
> Why do you feel I was incorrect in citing directive guidance?
>

Because nothing in the AIM supports your position. You're looking for an
FAR.

[Steven P. McNicoll]

"Sam Spade" > wrote in message
news:_YG4g.174531$bm6.134045@fed1read04...
>
> And, you point being?
>

You claimed use of handheld GPS is prohibited by the FAA for use as primary
nav for IFR in Part 91 operations. You were challenged to cite the
applicable regulation. You cited the AIM, which is not regulatory. Only an
FAR can support your claim.

[Steven P. McNicoll]

"Sam Spade" > wrote in message
news:N1H4g.174532$bm6.101296@fed1read04...
>
> You need to get a better grasp on your employer's policy and
> implementation programs. Headquarters has made it abundantly clear that
> GPS cannot be used for primary IFR navigation unless the device complies
> with TSO 129, 145, or 146 (or is a certified FMS/LNAV integrated
> platform).
>

Please cite the FAR in which that has been made clear.


>
> Then, the avionics manufactors of 129, 145, or 146 boxes must
> prove compliance before they receive certification. And, then the device
> has to be installed in an approved manner to satisfy Part 23.
>

We're talking about handheld GPS.


>
> The AIM material I cited reflects that policy.
>

When that policy is promulgated in an FAR it will become legally binding.

[Steven P. McNicoll]

"Sam Spade" > wrote in message
news:hWG4g.174529$bm6.47479@fed1read04...
>
> In your view of the world, lots of FSDO inspectors are irrational.
>

I don't know if lots of them are, but I do know that those I have
communicated with on this subject tend to be.


>
> I won't go into the view that FSDO inspectors have of ATC personnel.
>

Well, I knew one that didn't like them at all. Of course, his view was of
someone that went to FSDO after washing out of ATC. I've heard of other
FSDO types that went there after washing out of ATC, I've never heard of
anyone washing out of FSDO and moving up to ATC.


>
> As to all the point/counterpoint about handhelds and Part 23, we agree
> that a "non-installed" handheld is not subject to any provision of Part
> 23. What you fail to understand is that, unless a particular item of
> avionics that is to be used for primary IFR navigation is so certified, it
> cannot be used for primary IFR navigation.
>

Please cite the applicable FAR.


>
> Further, if it is certified
> for primary IFR navigation, it then has to be installed in compliance with
> Part 23. A handheld doesn't quite make the program.
>

Please cite the applicable FAR.


>
> And, please, don't tell me to prove it. Your resource is any G/A
> maintenance inspector at your local, friendly FAA FSDO.
>

I've already directed this question at a number of FSDOs. None of them
could cite the applicable FAR. The reason none of them could cite an
applicable FAR is there is none and thus use of a handheld GPS for IFR
enroute use in US controlled airspace is perfectly legal.

[Steven P. McNicoll]

"Ron Lee" > wrote in message
...
>
> Steven, since you are so sure of yourself please go make an IFR flight
> in VFR conditions with an FAA type who can bust you for doing bad
> things.
>

Please define "bad things".


>
> Then while on an IFR flight plan resort to only using your
> handheld and dare him to cite you.
>

What do you think he'd cite me with?

[Ron Lee]

Just do it Steven and report back to us.

Ron Lee




"Steven P. McNicoll" > wrote:

>
>"Ron Lee" > wrote in message
...
>>
>> Steven, since you are so sure of yourself please go make an IFR flight
>> in VFR conditions with an FAA type who can bust you for doing bad
>> things.
>>
>
>Please define "bad things".
>
>
>>
>> Then while on an IFR flight plan resort to only using your
>> handheld and dare him to cite you.
>>
>
>What do you think he'd cite me with?
>
>

[Steven P. McNicoll]

"Ron Lee" > wrote in message
...
>
> Just do it Steven and report back to us.
>

In other words, you haven't the slightest idea about what I could be cited
with.

[Ron Lee]

"Steven P. McNicoll" > wrote:

>
>"Ron Lee" > wrote in message
...
>>
>> Just do it Steven and report back to us.
>>
>
>In other words, you haven't the slightest idea about what I could be cited
>with.

No, in other words, you rant and rave about something and you won't
actually go do it. Prove to us unenlightened souls that you are
right.

Ron Lee

[Steven P. McNicoll]

"Ron Lee" > wrote in message
...
>
> No, in other words, you rant and rave about something and you won't
> actually go do it. Prove to us unenlightened souls that you are
> right.
>

I'll make the flight if you're willing to pay for it. If not you can either
accept a FSDO review of a hypothetical flight or remain an unenlightened
soul.

[Cox]

> Please cite the FAR in which that has been made clear.

FAA Order 8360.38a says the equipment must comply with TSO C129. FAA Orders
are incorporated into CFR 14.


> When that policy is promulgated in an FAR it will become legally binding.

I think a pilot using a handheld GPS (not complying with TSO C129) under IFR
would be cited with:
91.13 - Careless and Reckless
91.205(d)(2) - appropriate navigation equipment

[Steven P. McNicoll]

"Cox" > wrote in message
news:uRccg.31356$fG3.21351@dukeread09...
>
> FAA Order 8360.38a says the equipment must comply with TSO C129. FAA
> Orders are incorporated into CFR 14.
>

Title 1 CFR Part 51 provides for the incorporation of publications by
reference. One such example in the FARs is the incorporation of FAA Order
7400.9N, Airspace Designations and Reporting Points, in FAR 71.1. Please
cite the FAR that incorporates FAA Order 8360.38A by reference.


>
> I think a pilot using a handheld GPS (not complying with TSO C129) under
> IFR would be cited with:
> 91.13 - Careless and Reckless
> 91.205(d)(2) - appropriate navigation equipment
>

FAR 91.13(a) prohibits the operation of an aircraft in a careless or
reckless manner so as to endanger the life or property of another. Use of a
handheld GPS under IFR in US controlled airspace does not endanger any life
or any property.

FAR 91.205(d)(2) requires a two-way radio communications system and
navigational equipment appropriate to the ground facilities to be used. It
does not prohibit the use of any equipment beyond what is required to be
installed.

[Newps]

> "Cox" > wrote in message
>
>
>>I think a pilot using a handheld GPS (not complying with TSO C129) under
>>IFR would be cited with:
>>91.13 - Careless and Reckless

That would be automatic in any enforcement case of this type.

[Ron Lee]

Haven't I done that? Didn't I tell you that no approval is required
for
>enroute use of a handheld GPS in the US? Didn't I tell you that the mere
>existence of a TSO does not prohibit the use of equipment that hasn't been
>demonstrated to meet the standard? Didn't I tell you TSOs are not binding
>unless there is an FAR that requires the TSO to be complied with? Didn't I
>tell you there are TSOs in existence that cover the "approval" of a great
>many things, but you don't have to use "approved" equipment in any operation
>unless required to do so by the FARs? Isn't telling you those things
>telling you something?
>
>
Steven, since you are so sure of yourself please go make an IFR flight
in VFR conditions with an FAA type who can bust you for doing bad
things. Then while on an IFR flight plan resort to only using your
handheld and dare him to cite you.

Ron Lee