"GPS Unreliable" NOTAM

Richard Kaplan wrote:

The recent thread regarding GPS as the sole navaid sometime in the future
has focused on terrorism as the "what if" scenario.

I am not focusing specifically on terrorism in my concern the need for
GPS redundancy; I am simply observing that there is no system or device I am
aware of anywhere in aviation which works 100% of the time, so certainly it
is always worh having a backup. Even if GPS has 12 satellites, it seems
clear by common sense that the best backup system would use a technology
different from GPS.

With that as background, look at the following NOTAM, which is currently
available on DUAT. We can theorize all we want about whether this NOTAM
exists due to military testing or some atmospheric irregularity or whatever,
but the point is that the NOTAM really is out there and will be effective in
a few days. If my plane had nothing but GPS-based avionics, what would my
options be?

GPS 07/015 ZDC GPS UNRELIABLE WITHIN A 100 NM RADIUS OF PATUXENT
VORTAC (PXT) AT 10,000 MSL THROUGH FL400, AND DECREASING IN AREA
WITH DECREASE IN ALTITUDE TO 80 NM RADIUS AT 4000 FT AGL
1200-2000 DLY WEF 0307211200-0307252000


Again, there are toy airplanes then there are real airplanes. All high-end jets
have triple IRUs feeding position to the FMS and LNAV. So, if the primary nav
sensor shoots craps around Podunk, Merrykanasa, you just coast along using
triple-mized inertial position until the GPS kicks back in.

wrote:


sensor shoots craps around Podunk, Merrykanasa, you just coast along using
triple-mized inertial position until the GPS kicks back in.

Make that triple-mixed.

"C J Campbell" wrote in message
...

If your airplane had nothing but VOR-based avionics, and the PATUXENT VOR
itself was notamed out, what would your options be? There are plenty of


My options would be GPS (preferably) or NDB or Loran.


Frankly, your rantings are becoming tiresome. You have said nothing
critical
of dependence on GPS that cannot also be said of the current dependence on
VOR.

Absolutely true. I agree that we need alternatives to VOR just like we
need alternatives to GPS. I also think that a transition to a system which
emphasizes GPS is desirable. I just do not think we can put all our eggs in
the GPS basket any more than we can put them all in the VOR basket.


I especially am tired of the 'what-if' games, such as Andraka's comment
that

"What-if" is the most important question any pilot can ask, especailly an
instrument pilot.

I do not know how many people have to die before Mr. Kaplan and others of
his ilk finally realize that there is something fundamentally wrong with
ground-based radio navigation. Yes, at one time it was all we had. But it
is

I think this is quite a bit of hyperbole. Again, GPS is terrific and we
should move forward. We just cannot make it the exclusive navigation system
without any backup. Surely there is no one who will argue that a GPS-only
world is safer than a GPS/ILS/VOR world -- cheaper maybe, but safer?

--
Richard Kaplan, CFII

www.flyimc.com

"Richard Kaplan" wrote in message
...
| "C J Campbell" wrote in message
| ...
|
|
| I do not know how many people have to die before Mr. Kaplan and others
of
| his ilk finally realize that there is something fundamentally wrong with
| ground-based radio navigation. Yes, at one time it was all we had. But
it
| is
|
| I think this is quite a bit of hyperbole.

Of course it is. And it was deliberate, too. I admit that it was very
difficult to come up with hyperbole equivalent to that of airplanes falling
out of the sky because of terrorists jamming the GPS system, though.

"C J Campbell" wrote in message ...

difficult to come up with hyperbole equivalent to that of airplanes falling
out of the sky because of terrorists jamming the GPS system, though.

You are the one who keeps mentioning terrorists jamming the GPS
system.

Look at the title of this thread -- I am talking about the very real
NOTAM which is actually published right now regarding GPS Unreliable
in a given region. This is no hyperbole on my part -- it is a real
NOTAM.

--
Richard Kaplan, CFII

www.flyimc.com

"Richard Kaplan" wrote in message
om...
| "C J Campbell" wrote in message
...
|
| difficult to come up with hyperbole equivalent to that of airplanes
falling
| out of the sky because of terrorists jamming the GPS system, though.
|
| You are the one who keeps mentioning terrorists jamming the GPS
| system.
|

Am I indeed? I believe I mentioned them precisely once. Perhaps you have me
confused with somebody else.

I wouldn't have made the comment if it hadn't actually happened. Both in the P
static and icing encounters I lost comm but not nav. The p-static made the
Loran unusable, but not the VORs. GPS is great, but as I and Mr Kaplan have
said, we prefer to not put all the eggs in one basket. I'll be keeping the ADF
and Loran in my panel as long as there are stations to use them on. I also
carry handhelds as backups for the electrical system.



C J Campbell wrote:

I especially am tired of the 'what-if' games, such as Andraka's comment that
you have no out if you also lose your comms. Get real. We are beginning to
talk about scenarios where you have complete failure of the electrical
system here. Do you realistically expect your VORs to continue working under
such conditions? If you have static or ice building up on your comm
antennae, you have static or ice building up on your VOR antennae as well.


--
--Ray Andraka, P.E.
President, the Andraka Consulting Group, Inc.
401/884-7930 Fax 401/884-7950
email
http://www.andraka.com

"They that give up essential liberty to obtain a little
temporary safety deserve neither liberty nor safety."
-Benjamin Franklin, 1759

"Richard Kaplan" wrote in message ...

With that as background, look at the following NOTAM, which is currently
available on DUAT. We can theorize all we want about whether this NOTAM
exists due to military testing or some atmospheric irregularity or whatever,
but the point is that the NOTAM really is out there and will be effective in
a few days. If my plane had nothing but GPS-based avionics, what would my
options be?

From my discussions with some stationed there, it is airborne GPS jamming testing.

On Mon, 21 Jul 2003 14:14:57 -0400, "Ron Natalie"
wrote:


"Richard Kaplan" wrote in message ...

With that as background, look at the following NOTAM, which is currently
available on DUAT. We can theorize all we want about whether this NOTAM
exists due to military testing or some atmospheric irregularity or whatever,
but the point is that the NOTAM really is out there and will be effective in
a few days. If my plane had nothing but GPS-based avionics, what would my
options be?

From my discussions with some stationed there, it is airborne GPS jamming testing.

Seeing those NOTAMS is not rare. Some have mentioned testing. Most
are in the western states, probably as it would cause less disruption.

I've done five flight plans this year that were direct 3BS BJC and 4
of them had GPS NOTAMS which included the expected distances from the
area versus the altitude.

GPS may be the best thing since fried eggs, but it's still a good idea
to keep something for back up.

Contrary to an earlier statement, the back up system does not have to
be more reliable than the primary system. It doesn't even have to be
as good as...As long as the failure rate is low enough, the odds of
both systems going out at the same time are very low.

"Last I heard" the FAA had backed off on the GPS only idea and is
considering carrying the VORs for some time to come. With some form
of backup in the future.

Last week I read where they had just commissioned a new NDB/LOM
I believe AVWeb had a story on the WAAS and how long it will probably
take to get it widely implemented.

A big advantage for WAAS is "as I understand it", one station can
service a number of nearby airports.depending on distances and
minimums.

For most of us it's not "one or the other". GPS wins hands down when
the two are compared, but there is most likely going to be a ground
based backup system (of some sort) far into the future.

I like the idea of GPS and a solid state inertial guidance
system...Which I think will show up in a form a good percent of us can
afford.

Roger Halstead (K8RI EN73 & ARRL Life Member)
www.rogerhalstead.com
N833R World's oldest Debonair? (S# CD-2)

Well, you still can't get HIWAS on a GPS. I suppose if GPS ever became the
sole navigation system we would have to depend on downloaded weather.