Clarification about the term "GPS Shutdown"

[Hans-Georg Michna]

I have yet to see a single pilot who is
going to entrust his life (let alone that of his passengers) to the
autopilot for landing.

Jürgen,

are you sure you know what you're talking about? Ever heard of
Cat. 3B Autoland? That's not even new.

I think the majority of airline landings are done by the
autopilot these days.

Or did you not mean what you wrote?

Hans-Georg

 

[Mxsmanic]

The original information was that the White House reserves itself the
right to shut down GPS in emergency situations.

Same thing.

You then claimed that this would cause more damage than
a terrorist attack.

That's what the available evidence indicates.

And it has been shown that those who need that precision (aircraft and
cars) can achieve it without GPS easily, and that it's not all that
important for ships.

It's extremely important for ships, and marine navigation requires this
precision.

Using autopilot for landing?
Obviously.

Pilots still prefer to land manually ...

Maybe, but that is their choice, not a requirement (in many cases).

... AFAIK - if only to proof themselves that their job can't be downsized
to be replaced by a bit of silicon.

Actually, they _can_ be replaced by a piece of silicon, for normal
flight. About the only purpose they serve is to handle extremely rare
exceptions, and to communicate on the radio.

So what you mean is we can't shut down GPS because people don't know
how to do their job?

No, there are other reasons why we should not shut down GPS. But this
is an additional reason, that much is true.

 

[Hans-Georg Michna]

Using autopilot for landing? Pilots still prefer to land manually,
AFAIK - if only to proof themselves that their job can't be downsized
to be replaced by a bit of silicon.

Jürgen,

Lufthansa recommends automatic landings. They seem to think that
the pilots should do their manual landings in the simulator.

Hans-Georg

 

[Alan Browne]

Alan Browne writes:




Well, you're half right: Ships have been navigating without GPS for many
years.

What accuracy was used and needed prior to GPS was sufficiently high for the use.

 

[Alan Browne]

Signing off and switching back to reality.

Teh reality you should consider is the reality in which mariners have
successfully navigated for a couple centuries without GPS. Does GPS make it
better, faster, easier, more accurate? Yes. Can mariners function without it?
Absolutely. Any mariner who cannot, it not a mariner.

 

[Alan Browne]

Alan Browne writes:




Yes, and that's way too long for a ship.




... right.

No. Sadly misinformed is all. Ignorance and assumption make a poor platform.

 

[Mxsmanic]

What accuracy was used and needed prior to GPS was
sufficiently high for the use.

Requirements have evolved since then. Christopher Columbus didn't have
to worry about colliding with a supertanker on his way to America.

 

[Mxsmanic]

Teh reality you should consider is the reality in which mariners have
successfully navigated for a couple centuries without GPS.

That's past history, not present reality.

 

[Alan Browne]

That's past history, not present reality.

I suppose you can't boil water over a fire either.

 

[Alan Browne]

Alan Browne writes:




Requirements have evolved since then. Christopher Columbus didn't have
to worry about colliding with a supertanker on his way to America.

All ships carry 2 or three radars for navigation and collision avoidance.
Almost all fishing boats. Almost all sailboats and pleasure craft of a
'serious' size. Unlike aircraft, ships can reduce their speed considerably in
waters where there is more traffic.

eg: this issue is a repeat of sorts of the aviation issue. I don't know enough
about marine navigation and law to argue it to death, but to an even greater
degree than aviation, shipping can adapt quickly to a non-GPS world for the
contemplated emergency period.

Again, GPS is a blessing but its absence is not neccesarilly a curse.

 

[Dale DePriest]

Alan Browne writes:




Requirements have evolved since then. Christopher Columbus didn't have
to worry about colliding with a supertanker on his way to America.

However, he did have to worry on the way back. Of course all you had to
do was find the coast of a continent and then follow it but he was
almost killed in hostile area 100's of miles from where he needed to be.

Dale

 

[Mxsmanic]

All ships carry 2 or three radars for navigation and collision avoidance.

Apparently they must carry more than that, now.

Unlike aircraft, ships can reduce their speed considerably in
waters where there is more traffic.

Unlike aircraft, ships weigh 100,000 tons and will continue to coast
unstoppably for miles after being "stopped." Just turning large ships
can be a challenge.

 

[Mxsmanic]

However, he did have to worry on the way back. Of course all you had to
do was find the coast of a continent and then follow it but he was
almost killed in hostile area 100's of miles from where he needed to be.

In those days it was possible to remain at a specific latitude, but
longitude was impossible to determine. If you knew you left land at 46°
north latitude, you could turn around and head back at the same latitude
and eventually find the same land. But if you moved to a different
latitude, you could sail indefinitely and never see any land. Many
sailors died this way.

 

[Chuck Taylor]

Alan Browne writes:

Unlike aircraft, ships weigh 100,000 tons and will continue to coast
unstoppably for miles after being "stopped."

Would this not be precisely why they might ***reduce their speed
considerably in waters where there is more traffic***?


("Unlike aircraft"...what's the stopping distance of a 727 at
altitude, by the way?)

 

[High Sierra]

all garbage snipped

 

[Frank Looper]

("Unlike aircraft"...what's the stopping distance of a 727 at
altitude, by the way?)

Has a lot to do with the altitude...

 

[Mxsmanic]

Would this not be precisely why they might ***reduce their speed
considerably in waters where there is more traffic***?

There's a limit to how much they can slow down and still get the job
done.

"Unlike aircraft"...what's the stopping distance of a 727 at
altitude, by the way?

That depends on what it hits.

 

[Alan Browne]

Alan Browne writes:




Apparently they must carry more than that, now.

No. That's all they carried before.

Unlike aircraft, ships weigh 100,000 tons and will continue to coast
unstoppably for miles after being "stopped." Just turning large ships
can be a challenge.

And GPS magically can stop a ship? Wow! I didn't know that!

 

[Chuck Taylor]

There's a limit to how much they can slow down and still get the job
done.

Getouttahere. Really?

 

[Mxsmanic]

Getouttahere. Really?

Yes.