IFR with a VFR GPS

"Tauno Voipio" wrote in message
...

There is one fundamental difference to other means
of IFR navigation: It is impossible to test and
approve the GPS signal. For the other NAVAIDs the
station can be measured on ground and fly the measuring
flights and compare the results with the specs in
ICAO Annex 10, and that's it.

Been there - done that.


Why is it impossible to test the GPS signal?

wrote:

Mark T. Dame wrote:

Now, if we're talking about precision GPS approaches, that's a
different story. But enroute navigation (and possibly even
non-precision GPS approaches) should be just as safe with a handheld
as a panel mount.

You will usually have as good of accuracy with a hand-held (with an
external antenna, but you lack the interity because you don't have
approach RAIM.

Would this ever matter?

Not really. As long as your hand held can tell you when you when it
doesn't have enough satellites for 2D navigation. In which case, you go
missed just like you would with a panel mount.


Since there aren't any precision RNAV IAPs, other than LPV (which
requires WAAAS) I fail to see your distinction between precision and
non-precision.

Which is my point: if you have a panel mount without WAAS, it's no
better than a handheld. So why shouldn't you be allowed to use a
handheld for the same operations as a panel mount IFR approved GPS?

It really comes down to not being able to control the installation. But
the installation is all about signal reception. If the FAA (or other
nations' equivalents) sets a reception standard for IFR operations, the
GPS manufactures can update the software to tell you when you are not
receiving IFR quality signal (just like at least some do for 2D and 3D
navigation). So technically it's completely plausible to have an IFR
certified handheld.

Bureaucratically is a different story.


-m
--
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Jonathan Goodish wrote:

I used to own a 195, and I'm pretty sure that it alerted me when it lost
position, but I no longer own it, so I can't verify if or how this
functionality existed.

I had a 195 and as I recall, it popped up a message when it lost signal
(full or partial). I only saw it once in actual use. I normally only
saw this when I went carried inside after playing with it outside.


-m
--
## Mark T. Dame
## VP, Product Development
## MFM Software, Inc. (http://www.mfm.com/)
"An important, but often overlooked, feature of running a computer
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Right, but some of the old units (the 10 year old but still widely
used Garmin 195 being one case that keeps popping up anecdotally)
don't implement this properly.
I used to own a 195, and I'm pretty sure that it alerted me when it lost
position, but I no longer own it, so I can't verify if or how this
functionality existed. It's easy enough to implemented I can't imagine
any hand held manufacturer excluding it.

that's exactly why there are IFR-certified GPS's that must adhere to
some basic design, operating principles and functionability
and then there are 'other' GPS's. There
is no such thing as a 'VFR GPS.' It is just an 'other' GPS. It could
be a Garmin Forerunner to a Garmin 396. As long as it is not certified,
who knows where it falls between those. Now we all know the 396 is
on the same level as a IFR-certified GPS but all those others leave
a LOT of room for interpretation in the design none of which the user
has access to (manufacturer proprietary).

Gerald

Vintage Garmin 195, updated software and database, has them, and
approaches as well.


when was the last time you updated the database?

Gerald

"Steven P. McNicoll" wrote:

That's unquestionable only if the VFR GPS was the only nav gear aboard the
airplane. I think that unlikely.

The pilot was cleared to fly a GPS approach in an aircraft without an IFR
certified GPS. How else is he going to navigate the approach course?

--
Peter
























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Jose wrote:

It is =not= unquestionable that this accident pilot did. It is known
that a VFR GPS was found at the accident site.

The pilot was cleared to fly a GPS approach into the airport and struck the
tower along the approach course. How else was he navigating, if not by the
VFR GPS?

Again, I agree that hitting the tower was not due to the navigation device
used.

--
Peter
























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Jose wrote:

Perhaps, but the reason for my reference to the accident in this
thread was
to support my point that the possibility exists for instrument-rated
pilots
to use a VFR GPS as the only means of navigation. It is unquestionable
that this accident pilot did.


It is =not= unquestionable that this accident pilot did. It is known
that a VFR GPS was found at the accident site. If a tuna sandwich was
found there, would that be incontrivertable evidence that the pilot was
relying solely on a tuna sandwich for IFR flight?

Jose
If he had asked for the Tuna Fish approach to his destination I would
agree. He asked for the GPS approach and the only GPS on board his
aircraft was the hand held.

If he had asked for the Tuna Fish approach to his destination I would agree. He asked for the GPS approach and the only GPS on board his aircraft was the hand held.

Oh.

Jose
--
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"Peter R." wrote in message
...

The pilot was cleared to fly a GPS approach in an aircraft without an IFR
certified GPS. How else is he going to navigate the approach course?


Irrelevant. The presence of a VFR GPS does not preclude the use of any
other navigational systems. Given that the aircraft struck a tower that was
very nearly on the FAC centerline it appears that navigating the approach
course was not a problem.