GPS and old-fashioned thinking?

In article ,
says...

I think the only problem with GPS is the human interface.

I disagree. I think there is a more important problem. If you're flying direct
routes and RNAV with GPS as primary(and only random route) source of
navigation, in the event of a GPS signal degradation, you have a bit of a
balancing act to do to get back to "legacy" navigation. If you're in the
middle of the Great Plains that's no issue, but if you're shooting an approach
to White Plains it may be.

My point is we were on the way toward an integrated RNAV system until GPS came
along and we decided we have to hurry and trash everything else. What we need,
I believe, is an RNAV system which allows us to seamlessly maintain random
route navigation in the event of a primary source failure (GPS). eLoran would
be one possible answer, but so would existing ground-based (VOR-DME) systems,
if your box is programmed for this.

The "all-or-nothing" approach to GPS (I know this is an exaggeration - but
only a slight one) is contrary to everything we learn and practice in aviation
- where we're supposed to have an answer, and hopefully a good answer, to
every eventuality.

I love GPS, and I see no problem in being highly reliant on it, because it is
intrinsically reliable - however I believe it would be practical and desirable
to build a system that maintains full RNAV capability in the event of a loss
in GPS integrity.

G Faris

john smith wrote:

Knowing EXACTLY where I am at all times and being able to direct to
pretty much everywhere (just the prohibited and restricted airspaces,
oh and TFR's to go around), save time, money and fuel.

And you cannot do that with a map and compass?

A *real* pilot doesn't need a map or compass -- that kind of technology
just makes you too lazy to fly low and read highway signs.


All the best,


David

G Farris wrote:

I disagree. I think there is a more important problem. If you're flying direct
routes and RNAV with GPS as primary(and only random route) source of
navigation, in the event of a GPS signal degradation, you have a bit of a
balancing act to do to get back to "legacy" navigation. If you're in the
middle of the Great Plains that's no issue, but if you're shooting an approach
to White Plains it may be.

Wouldn't you be in the same situation if you were shooting an ILS
approach and the localizer went U/S?


All the best,


David

"Doug" wrote:
Also, it makes flight planning a breeze. No legs to figure. Just click
in your route, check for restricted/prohibited airspace and TFR's and
go direct!

It helps to take a glance at the terrain too. I've got a flight planning
exercise I give to people to plan a trip to a destination on the other side
of what passes for a mountain range around here (the Catskills). I'll give
them a weather forecast with ceilings just about at the mountain tops.
It's amazing how many come back to me with "GPS direct" and seem to be
totally clueless that they've just planed a trip into cumulogranite.

G Farris wrote:
I love GPS, and I see no problem in being highly reliant on it, because
it is intrinsically reliable - however I believe it would be practical
and desirable to build a system that maintains full RNAV capability in
the event of a loss in GPS integrity.

The big boys have it, it's called Inertial Nav. Whether that will ever
become an affordable reality for GA is anybody's guess, but stranger things
have happened. With the current crop of GPS gear on the market, there are
already spam cans equipped with better nav systems than some jets.

Here is something you have with a GPS that you don't have with most
other Nav -- GROUNDSPEED. (Yes you can get it if you have DME and are
flying to/from the station). How does that help? Helps with fuel
planning and time. Will you be flying at night or will you make it
before nightfall?

I once used GPS for deciding if I should attempt flying ridge lift. I
was heavily loaded in my Amphib. I can climb to 13000' I need to get
over Corona, but its not easy. Usually there is a west wind causing
ridgelift as you fly west to east. As I climbed, it was apparent that I
wasn't going to make it without circling. But...that west wind..IF I
was SURE it existed. So I turned into the wind (my destination was
east) to make sure and checked my GS with my airspeed. Sure enough it
was there. I went close to the ridge (so close you didn't want to be
there if there were downdrafts), and the wind just lifted me right up
and over the pass. WAY COOL!

Ron Lee wrote:
Bob Noel wrote:


In article xl0kf.62898$qw.59268@fed1read07, wrote:


The FAA, and the rest of the world as well, want to eventually shut-down
the VORs. The only remaining ground-based systems will be ILSes.

DME, and probably MLS, will be around for a while longer.


Don't count on it...elimination of all ground-based navaids. Even the
FAA has reconsidered this flawed from the beginning concept.

Ron Lee

Which FAA? ;-)

As the budget crunch deepens, and it will, the pressure to do away with
most ground facilities other than ILS will be irresistable.

One variation is to shut down the VORs but leave "geometrically
desirable" DME facilites going until the legacy air carrer LNAV
platforms retire. That would be a whole lot less expensive than
maintaining aging VOR facilities.

The bean counters want to do away with primary radars, too. But, so
far, the security-minded have stopped that planning.

G Farris wrote:



I love GPS, and I see no problem in being highly reliant on it, because it is
intrinsically reliable - however I believe it would be practical and desirable
to build a system that maintains full RNAV capability in the event of a loss
in GPS integrity.

You're thinking in light aircraft terms. All modern air carrier jets and
biz jets have IRUs, which will provide a decent RNAV platform for a
reasonable length of time in the terminal area and for a very long time
en route.

wrote:
The bean counters want to do away with primary radars, too. But, so
far, the security-minded have stopped that planning.

What does it mean to "do away with primary radar"? The antennae are
co-located and the systems are already built. What money would be saved by
turning the primary part of the system off? It's not even like they rotate
on different shafts so you can save a little on lubricating the bearings or
powering down the motor that makes it go round and round.

Anyway, if we turn off the primary radar, we'll only be able to see things
that want to be seen. The libertarian in me likes that idea, but I'm
enough of a realist to understand that the people intent on blowing things
up are probably smart enough to turn their transponders off.

We will be going to a GPS based system. Alaska has tried this system
under the Capstone name. Basically you will broadcast to ATC your
position and ATC will use that information just as they use the radar
information today.



Roy Smith wrote:
wrote:

The bean counters want to do away with primary radars, too. But, so
far, the security-minded have stopped that planning.


What does it mean to "do away with primary radar"? The antennae are
co-located and the systems are already built. What money would be saved by
turning the primary part of the system off? It's not even like they rotate
on different shafts so you can save a little on lubricating the bearings or
powering down the motor that makes it go round and round.

Anyway, if we turn off the primary radar, we'll only be able to see things
that want to be seen. The libertarian in me likes that idea, but I'm
enough of a realist to understand that the people intent on blowing things
up are probably smart enough to turn their transponders off.