GPS approach safety case

"John R. Copeland" wrote in message
...

Interesting, if that A1 need is indeed the case.
Approach capability seems an odd requirement in equipment mandated only
for high-altitude flight.
But logic shouldn't be applied recklessly to regulations, should it?

Reveiwing some historical material, I think I'm mistaken. B-RNAV mandated
health-word checking and pseudorange step detection which caused some grief
against US standards, but I believe that was about the difference between
C129 and C129a.

Julian Scarfe

Julian, so what is the reason no gps approaches in the UK?
What is the CAA waiting for?
Are there not some fields that could benefit from an approach that can
be lined up exactly with the centerline?
Is it only politics?
Stan

On Sun, 6 Jun 2004 19:11:38 +0100, "Julian Scarfe"
wrote:

"S Green" wrote in message
...

tend to agree. Look who controls the GPS infrastructure. without
assurances
that the integrity of the system was not at the whim of the US Department
of
Defence, I cannot see the UK authorities being prepared to rely on GPS.
Ultimately this does become a safety issue.

But the UK authorities already rely on GPS at least to the same extent. As
well as having to carry ADF, VOR and DME for IFR flight in controlled
airspace, anyone wanting to fly at or above FL100 (note that that's
equivalent to 10,000 ft, perhaps not what US pilots are used to for flight
levels) needs B-RNAV (B for Basic). The only economical way of meeting the
B-RNAV requirement is to carry a TSO-C129a class A GPS receiver. I have in
the back of my mind that, ironically, it has to be class A1 (approach
capable) because B-RNAV imposes some extra requirements beyond the A2 spec,
but I'm not sure. Thus if the GPS infrastructure disappears, the
unavailability of a few overlay approaches or even standalone GPS approaches
is the least of our problems!

I'd like to see:

a) a relaxation in the requirement to carry all of ADF, VOR *and* DME if
there's also a TSO-C129a GPS receiver and the conventional nav equipment
allows sensible backup.

b) the ability to fly overlay NDB approaches without ADF, again provided nav
equipment is carried to enable an approach at an alternate.

Sometimes, and I know its rare, politics falls before a rational argument...

Julian Scarfe

At the risk of sounding endlessly questioning,

How would turning off GPS suddenly cause the death of thousands. Other
navigational equipment is required (at least in the US). And the GPS
system IS a DOD facility, operated by the US. I dont see any obligation
being promulgated on us to the rest of the world.

The Russians have their own version dont they? Do you think they have
any sense of responsibility to any US users who may happen to be using
their system?

Dave

C J Campbell wrote:
"S Green" wrote in message
...

No pointers. Emprically, I'd say they are working great in the US. The

issue

is politics, not safety.


tend to agree. Look who controls the GPS infrastructure. without

assurances

that the integrity of the system was not at the whim of the US Department

of

Defence, I cannot see the UK authorities being prepared to rely on GPS.
Ultimately this does become a safety issue.



Are you seriously suggesting that the DOD would on a whim turn off all the
GPS signals and possibly cause thousands of people to die in landing
accidents? Um, yeah -- let's see:

"Mr. President, we had a terrorist threat of condition chartreuse today, so
we decided to kill thousands of people at random all over the world by
turning off the GPS system. When the terrorists actually blew up London, we
were unable to respond because the GPS system was turned off."

"Good job, boys. The political fallout over that should be minimal..."

No, I don't think so.

Next I suppose that you are going to claim that the British don't have any
radar that they could use in the event of a navigation system failure.

Or maybe your view really is just anti-American politics after all.

Julian Scarfe wrote:

"John R. Copeland" wrote in message
...

Interesting, if that A1 need is indeed the case.
Approach capability seems an odd requirement in equipment mandated only
for high-altitude flight.
But logic shouldn't be applied recklessly to regulations, should it?

Reveiwing some historical material, I think I'm mistaken. B-RNAV mandated
health-word checking and pseudorange step detection which caused some grief
against US standards, but I believe that was about the difference between
C129 and C129a.

Julian Scarfe

My recollection is that legacy RNAV aircraft can meet the Euro requirements
quite easily using DME/DME. Those clunky birds don't even have GPS.
Basically, Euro wanted crummy VOR aircraft out of the system.

OK, then, go to www.avionicsmagazine.com, June 2004 issue, and see the
future. My point is that within a few years, enhanced loran will be
available when GPS is not.

Bob Gardner

"Julian Scarfe" wrote in message
news:atLwc.293$%a5.124@newsfe5-win...
"Bob Gardner" wrote in message
...
Google "eurofix" to get a glimpse of the future.

Interesting, though it doesn't appear to have been updated for three years
(including the "live" test data)!

Julian

On Sun, 6 Jun 2004 19:11:38 +0100, "Julian Scarfe"
wrote:

"S Green" wrote in message
...

tend to agree. Look who controls the GPS infrastructure. without
assurances
that the integrity of the system was not at the whim of the US Department
of
Defence, I cannot see the UK authorities being prepared to rely on GPS.
Ultimately this does become a safety issue.

But the UK authorities already rely on GPS at least to the same extent. As
well as having to carry ADF, VOR and DME for IFR flight in controlled
airspace, anyone wanting to fly at or above FL100 (note that that's
equivalent to 10,000 ft, perhaps not what US pilots are used to for flight
levels) needs B-RNAV (B for Basic). The only economical way of meeting the
B-RNAV requirement is to carry a TSO-C129a class A GPS receiver. I have in

Here I have basick RNAV and it doesn't even have a GPS input.
Strictly the old KNS-80, but it is RNAV ... over here.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

the back of my mind that, ironically, it has to be class A1 (approach
capable) because B-RNAV imposes some extra requirements beyond the A2 spec,
but I'm not sure. Thus if the GPS infrastructure disappears, the
unavailability of a few overlay approaches or even standalone GPS approaches
is the least of our problems!

I'd like to see:

a) a relaxation in the requirement to carry all of ADF, VOR *and* DME if
there's also a TSO-C129a GPS receiver and the conventional nav equipment
allows sensible backup.

b) the ability to fly overlay NDB approaches without ADF, again provided nav
equipment is carried to enable an approach at an alternate.

Sometimes, and I know its rare, politics falls before a rational argument...

Julian Scarfe

On Sun, 6 Jun 2004 18:22:59 -0700, "Bob Gardner"
wrote:

OK, then, go to www.avionicsmagazine.com, June 2004 issue, and see the
future. My point is that within a few years, enhanced loran will be
available when GPS is not.

What is enhanced Loran? I've used the old Loran for years and have
developed a healthy distrust of its accuracy. It is handy and easy to
use, but I always want something to prove it's correct.

Multipathing, atmospherics, signal failure, complete loss of
navigation from the loran, 2 miles changes in position when changing
chains, and one time it had me at the wrong airport 20 miles from the
desired one. When I headed for home 2 hours later it still was
figuring I was in the wrong place. About 5 miles after I started
south it did a reset and low and behold, I was not back on course.
:-))

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

Bob Gardner

"Julian Scarfe" wrote in message
news:atLwc.293$%a5.124@newsfe5-win...
"Bob Gardner" wrote in message
...
Google "eurofix" to get a glimpse of the future.

Interesting, though it doesn't appear to have been updated for three years
(including the "live" test data)!

Julian

"Dave S" wrote in message
link.net...
At the risk of sounding endlessly questioning,

How would turning off GPS suddenly cause the death of thousands. Other
navigational equipment is required (at least in the US). And the GPS
system IS a DOD facility, operated by the US. I dont see any obligation
being promulgated on us to the rest of the world.

The Russians have their own version dont they? Do you think they have
any sense of responsibility to any US users who may happen to be using
their system?


Maybe that is Europe's problem. Somehow they can't understand that we are
not creepy, underhanded Europeans with an ulterior motive for everything.
They think that we must be just like they are.

So, if it is not to kill thousands of people, what is the hidden agenda
behind keeping DOD in charge of GPS? If turning off GPS will not endanger
anyone, what is the real objection that the Europeans have to it?

"Bob Gardner" wrote in message
...
OK, then, go to www.avionicsmagazine.com, June 2004 issue, and see the
future. My point is that within a few years, enhanced loran will be
available when GPS is not.


Loran has too many disadvantages. Its user base is too small. It is the same
problem that we have with all the rest of the aviation navigation system. It
is expensive and targeted too narrowly. GPS can be used by everyone. It is
simple, reliable, and cheap. Taxpayers and their representatives have little
incentive to continue funding an expensive, unreliable navigation
infrastructure that is used by only a tiny minority when that minority
(aviation) can just as easily use GPS just like everybody else.

The only real problem Europeans have with GPS is that it is not European.
Every other complaint they have about it is demonstrably silly.

Interesting, though it doesn't appear to have been updated for three
years
(including the "live" test data)!

"Bob Gardner" wrote in message
...
OK, then, go to www.avionicsmagazine.com, June 2004 issue, and see the
future. My point is that within a few years, enhanced loran will be
available when GPS is not.

Point taken. It seems to be the pages at Delft where Eurofix was developed
that have become stale, and I was a little hasty.

http://www.nels.org/

NW Europe LORAN System, seems to be the best source of info.

The system is still dependent on GPS (or rather, somebody's GNSS). It's yet
another way of doing DGPS.

Julian