IFR with a VFR GPS

Without getting into the middle of this general discussion, I'd like to point out
one thing about RAIM that seems to be misunderstood... One of the primary purposes
of RAIM is 'Predict" when a coverage 'problem' will occur and notify you before it
happens. Now, it can only predict such coverage problems (shortage of sats in view)
based on the orbits and times of the current sat configuration. It may not know if
a specific sat has gone 'out of service'.
Of course, out of service sats and normal coverage shortages are rare these days,
but they do happen. The IFR units will tell you about the upcoming problem BEFORE
it happens, while VFR units will only tell you after it has occurred.
A bigger problem is probably some of the testing that goes on in some locations
which make any GPS unit unusable. Watch those NOTAMs!



Peter wrote:

Jonathan Goodish wrote:


When my hand held Garmin loses enough sats for position calculation, I
receive an alarm on the unit (both visual and audible).


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.

: technological level than in the USA; the pilot magazines also largely
: ignore the IFR market. And IFR activity is even lower elsewhere in
: Europe.

Interesting. Perhaps some Canadians reading can pipe in on this idea. This
past summer while flying through Canada to Alaska, it certainly seemed like IFR was
the vast minority. I'm sure some of it was that I was in the sticks for a lot of the
time, but even in the relatively populated plains provinces, one didn't hear much
about IFR traffic (or traffic at all for that matter). Perhaps the US just has more
infrastructure so IFR is easier to do casually for PP?

Just a thought... not harping on anyone's turf...

-Cory

--

************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************

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
--
He who laughs, lasts.
for Email, make the obvious change in the address.

On Thu, 10 Nov 2005 22:36:32 -0500, Wizard of Draws
wrote:



My new Airmap 2000c, which was the reason for this thread, has them.
Vintage Garmin 195, updated software and database, has them, and
approaches as well.

Jose,

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?


In that case, it would of course be incontrovertible that both occupants
had the fish and the accident was caused by that.

--
Thomas Borchert (EDDH)

On Fri, 11 Nov 2005 04:05:09 GMT, John Theune
wrote:

What model is this? I've owned a Garmin 195 and Magellan 500 and both
started flashing if the lost the signal. I had a older non aviation Gps
and as I recall it did not flash when it lost signal. From my
experience and that of other pilots I've talked with all the aviation
GPS tell you when you lost signal. By the way how does your unit update
if you have lost the signal? I can see it freezing and displaying the
same info but how would it update?
John
I have 195. It lets you know when the signal is lost with a message
flashing. I also recall from reading the manual that it interpolates
position, etc. based on speed & heading at time of signal loss for a
short time (x number of seconds?) after loss of signal. If signal loss
is momentary it carries on normally.
I normally use my 195 plugged into aircraft power and with external
antenna. I have noticed that it interferes with the aircraft radio
equipment with static and various buzzes depending on frequency
selected. It does the same to my car radio when I use it there. I do
have some concern that it might interfere with the LOC/GS receiver for
instance, but I haven't seen it affect the accuracy when doing
practice ILS approaches with the unit on.
I have had it go bonkers once when flying very close to VOR Julian
(JLI). It gave the lost signal error message, along with bad position
& direction display, and would not re-aquire until i powered it down
and restarted.

On 11/11/2005 08:33, 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?

Perhaps not, but it might come in handy ;-)

Sorry, you're response (with which I agree 100%) just made me laugh.


Jose


--
Mark Hansen, PP-ASEL, Instrument Airplane
Sacramento, CA

"Peter R." wrote in message
...

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.


That's unquestionable only if the VFR GPS was the only nav gear aboard the
airplane. I think that unlikely. Since the aircraft struck a tower which
was only slightly off the FAC there's no reason to believe a navigational
error contributed to this accident.

Peter,

is that a lot of
(mostly VFR) pilots think that GPS is somehow unreliable, suspect,
dodgy, and they stick to the compass+stopwatch method.


not here in Germany.

--
Thomas Borchert (EDDH)

Peter,

Hmm. Data? Or at least some indications?

I live here.


I'm asking because I live in Germany - and here it isn't as you
describe.

--
Thomas Borchert (EDDH)