Re: "GPS Unreliable" NOTAM

[Robert Henry]

"Richard Kaplan" > wrote in message
...

>
> If my plane had nothing but GPS-based avionics, what would my
> options be?
>

Vectors.

[Paul Tomblin]

In a previous article, "Richard Kaplan" > said:
>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

Stay away from Patuxent?


--
Paul Tomblin >, not speaking for anybody
UNIX was half a billion (500000000) seconds old on
Tue Nov 5 00:53:20 1985 GMT (measuring since the time(2) epoch).
-- Andy Tannenbaum

[PlanetJ]

Is this the groundhog day location? Maybe GPS don't like groundhogs rooting
around?

>
>>
> 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
>
>
> --
> Richard Kaplan, CFII
>
> www.flyimc.com
>
>

[Ray Andraka]

Doesn't leave you any out should comm go down. I've had that
happen due to P-static, ice on the antenna, and problems with the
radio in a rental.

Robert Henry wrote:

> "Richard Kaplan" > wrote in message
> ...
>
> >
> > If my plane had nothing but GPS-based avionics, what would my
> > options be?
> >
>
> Vectors.

--
--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

[[email protected]]

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 re: 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.

[[email protected]]

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.

[Roy Smith]

> > > If my plane had nothing but GPS-based avionics, what would my
> > > options be?
> >
> > Vectors.

Ray Andraka > wrote:
> Doesn't leave you any out should comm go down. I've had that
> happen due to P-static, ice on the antenna, and problems with the
> radio in a rental.

Now you're theorizing about a simultaneous double system failure -- GPS
and communications. It's impossible, just extremely unlikely.

You can keep adding redundency to get the probability of incapacitation
as low as you want, but eventually an event will happen which will take
out all of your backups at the same time. What's the odds of a DC-10
having all three hydraulic system fail at the same time? They said it
was impossible, yet it happened (Souix City, uncontained failure of a
turbine disk).

By far the most likely cause of simultaneous GPS and COMM failure is
loss of ship's electrical power. It would take out your VOR, ILS,
Loran, too. The way to protect against that is multiple electrical
busses (like in twins), or battery backup and/or handheld devices.

[Roy Smith]

I wrote:
> It's impossible, just extremely unlikely.

Obviously, that's a typo. It should read "It's NOT impossible".

[Robert Henry]

"Ray Andraka" > wrote in message
...
> Doesn't leave you any out should comm go down. I've had that
> happen due to P-static, ice on the antenna, and problems with the
> radio in a rental.
>

Dial in last good frequency or 121.5 on the handheld.

[Richard Kaplan]

"Roy Smith" > wrote in message
...

> You can keep adding redundency to get the probability of incapacitation
> as low as you want, but eventually an event will happen which will take

Even assuming ATC has the manpower and frequency bandwidth to simultaneously
give vectors to all airplanes in an area of GPS outage, do we land nowhere
but runways with ASR approaches when it is IMC in that region until the GPS
service is resolved? And if we want to take off with a void clearance, do
we just consider airports without radar coverage down to the surface to be
unusable during IMC since there would be no navigation system available on
takeoff? Or maybe we just go by dead reckoning on takeoff? What happens if
there is a need for an emergency medical aircraft in a region where GPS is
out of service and no radar coverage is available? Central Pensylvania east
of Johnstown is just one excellent example --- there is a pretty
significantly sized area where there is no radar coverage available for
apporches, so I suppose if sole-nav GPS went out of service in the region
all the airports would just become VFR-only.

Clearly this situation is absurd, and for that reason we cannot and never
will switch to GPS-only navigation. Maybe there will be fewer but
strategically placed VORs and ILS systems but clearly there always must and
will remain some backup system besides just GPS.


--
Richard Kaplan, CFII

www.flyimc.com

[Ray Andraka]

In the case of the P-static, the handheld did no good. The incident in
the rental was the reason I bought the handheld.

Robert Henry wrote:

> "Ray Andraka" > wrote in message
> ...
> > Doesn't leave you any out should comm go down. I've had that
> > happen due to P-static, ice on the antenna, and problems with the
> > radio in a rental.
> >
>
> Dial in last good frequency or 121.5 on the handheld.

--
--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

[Roy Smith]

"Richard Kaplan" > wrote:
> Clearly this situation is absurd, and for that reason we cannot and never
> will switch to GPS-only navigation.

Is anybody saying that we should?

[News]

You can see some of the thinking on the FAA web site. Remember, these are
proposals for long term plans which are subject to change. It looks like the
plan is to shut down a lot of VOR's, but keep enough around so there is a
safety net (always within range of one VOR). Right now there are large parts
of the country where aircraft can simultaneous receive 3 or more VOR's at
the same time. By shutting down the "right" ones, the VOR system is cheaper
but still available for emergencies. If there were a sustained GPS outage
this would probably not help.

FAA's Transition Strategy for Navigation and Landing Services
http://www2.faa.gov/asd/briefings/05-19-03_Olsen_transition-brief.ppt

Free Flight
http://www2.faa.gov/nasarchitecture/blueprnt/2002Update/PDF/NAS_mod.pdf

Martin Van Ryswyk


"Richard Kaplan" > wrote in message
...
>
>
> "Roy Smith" > wrote in message
> ...
>
> > Is anybody saying that we should?
>
> Yes... a number of people posting on this thread have indicated that is
the
> plan, at least the LONG-TERM plan.
>
> --
> Richard Kaplan, CFII
>
> www.flyimc.com
>
>
>

[Richard Kaplan]

"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

[Ray Andraka]

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

[C J Campbell]

"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.

[Ron Natalie]

"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.

[Richard Kaplan]

"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

[C J Campbell]

"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.

[C J Campbell]

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.

[Roger Halstead]

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)