Can GPS be *too* accurate? Do I need some XTE??

== Bill Denton writes:

"Dan Girellini" wrote in message

I thought Class C services included IFR/VFR separation. Is that old/wrong
information?

No, separation is not provided by ATC.

Can you explain how I'm misinterpreting this from the AIM?

[3-2-4] Class C Airspace
....
e. Aircraft Separation. Separation is provided within the Class C airspace
and the outer area after two-way radio communications and radar contact
are established. VFR aircraft are separated from IFR aircraft within the
Class C airspace by any of the following:

1. Visual separation.

2. 500 feet vertical; except when operating beneath a heavy jet.

3. Target resolution.

--
PGP key at http://www.longhands.org/drg-pgp.txt Key Id:0x507D93DF

Bill Denton wrote:

No, separation is not provided by ATC.

ATC provides separation between IFR and VFR aircraft within the class C.

Dan Girellini ) wrote:

I thought Class C services included IFR/VFR separation. Is that old/wrong
information?

Yes, in the US VFR aircraft will receive separation services in class C
airspace, but is this the same level of service as the guaranteed
separation offered by class B? It is my understanding that the two are
not equivalent.

Hopefully one of the controllers who frequents this group will provide a
better explanation.



--
Peter

-- " " == Peter R writes:

Dan Girellini ) wrote:
I thought Class C services included IFR/VFR separation. Is that old/wrong
information?

Yes, in the US VFR aircraft will receive separation services in class C
airspace, but is this the same level of service as the guaranteed
separation offered by class B? It is my understanding that the two are not
equivalent.

What's in my Jepp text and afaict is confirmed in the AIM is that class C
provides only vfr/ifr separation whereas class B provides all acft separation
(ie vfr/vfr).

dan.

--
PGP key at http://www.longhands.org/drg-pgp.txt Key Id:0x507D93DF

Peter R. wrote:

Dan Girellini ) wrote:


I thought Class C services included IFR/VFR separation. Is that old/wrong
information?


Yes, in the US VFR aircraft will receive separation services in class C
airspace, but is this the same level of service as the guaranteed
separation offered by class B? It is my understanding that the two are
not equivalent.


Well, it's not 1000 or 3 but you won't hit 'em.

Dan Girellini ) wrote:

I thought Class C services included IFR/VFR separation. Is that old/wrong
information?

Yes, in the US VFR aircraft will receive separation services in class C
airspace, but is this the same level of service as the guaranteed
separation offered by class B? It is my understanding that the two are
not equivalent.

Hopefully one of the controllers who frequents this group will provide a
better explanation.



--
Peter

"Bill Denton" wrote in message
...
I noticed the later posts referenced a set of "rules" for setting up the
"error", but absent those, you are back to the same old game of chance.
What's to prevent another pilot from picking a corresponding "error" that
would still maintain the head-on courses?


Well, if *I* were choosing a *parallel offset*, it would always be to the
*right* of direct-track. Maybe the guy on the reciprocal track would think
to do the same.


And I don't know if this is a trick question, but if you are at 6000 (no
+500) wouldn't you be on an IFR flight plan, talking to ATC, and receiving
traffic advisories?

Well, I don't do IFR, but if you wish, change the scenario to my westbound
Cessna at 6500. And we are all "looking out", but just at the time we
appear as dots in each others windshield, my wife drops a water bottle that
rolls under my feet, so I bend down to get it, and she watches me. He's
been in the cockpit for 3 hours, in cruise descent, and his kid in the back
seat is a little antsy, and he's just realized he needs to look up a
frequency in the Airports and Frequency guide, because its kind of smudged
on his chart; he didn't think he'd need it, but what the hell.

The question was not meant to be tricky, nor to suggest that I am going to
throw my A/P onto the GPS and read the newspaper, instead of looking out the
window. I am just wondering out loud if super-accurate GPS nav creates a
"reduced chance" of horizontal clearance, over previous nav methods, given
the usual weaknesses and foibles of human pilots.






"Icebound" wrote in message
...
In the "good old" VOR days, it must have been pretty difficult to fly
down
the centerline of an airway (or of any direct track).

So an eastbound VFR/IFR aircraft descending from 7500/7000 to his
destination, was more than likely to avoid traffic... on the reciprocal
track passing him by at 6500 or 6000... by some significant horizontal
error-distance, even if they didn't see each other (big sky theory :-) ).

GPS horizontal accuracy with WAAS is already in the order of magnitude of
a
Cessna's wingspan, and some are talking about getting it down to mere
inches.

So the question is: If my Westbound Cessna at 6000 feet (with the
autopilot
keeping it happily on the GPS-track centerline) meets the descending
Bonanza
on the reciprocal track between the same two airports (using a similar
GPS/a-p combo), there is a distinct possibility that the horizontal
clearance may be zero...

...so is there anything in the current crop of GPS and/or Autopilot
systems
that allow me to maintain a small cross-track error of my choosing,
without
actually entering off-navaid-off-airport waypoints? ...or do we care; am
I
overly concerned???

The only time this would really be an issue would be if the other aircraft
were on an exact reciprocal course. And even if he used a corresponding
offset, he would still be 1,000 feet above or below you...



"Icebound" wrote in message
...

"Bill Denton" wrote in message
...
I noticed the later posts referenced a set of "rules" for setting up the
"error", but absent those, you are back to the same old game of chance.
What's to prevent another pilot from picking a corresponding "error"
that
would still maintain the head-on courses?


Well, if *I* were choosing a *parallel offset*, it would always be to the
*right* of direct-track. Maybe the guy on the reciprocal track would
think
to do the same.


And I don't know if this is a trick question, but if you are at 6000 (no
+500) wouldn't you be on an IFR flight plan, talking to ATC, and
receiving
traffic advisories?

Well, I don't do IFR, but if you wish, change the scenario to my westbound
Cessna at 6500. And we are all "looking out", but just at the time we
appear as dots in each others windshield, my wife drops a water bottle
that
rolls under my feet, so I bend down to get it, and she watches me. He's
been in the cockpit for 3 hours, in cruise descent, and his kid in the
back
seat is a little antsy, and he's just realized he needs to look up a
frequency in the Airports and Frequency guide, because its kind of smudged
on his chart; he didn't think he'd need it, but what the hell.

The question was not meant to be tricky, nor to suggest that I am going to
throw my A/P onto the GPS and read the newspaper, instead of looking out
the
window. I am just wondering out loud if super-accurate GPS nav creates a
"reduced chance" of horizontal clearance, over previous nav methods, given
the usual weaknesses and foibles of human pilots.






"Icebound" wrote in message
...
In the "good old" VOR days, it must have been pretty difficult to fly
down
the centerline of an airway (or of any direct track).

So an eastbound VFR/IFR aircraft descending from 7500/7000 to his
destination, was more than likely to avoid traffic... on the reciprocal
track passing him by at 6500 or 6000... by some significant horizontal
error-distance, even if they didn't see each other (big sky theory
:-) ).

GPS horizontal accuracy with WAAS is already in the order of magnitude
of
a
Cessna's wingspan, and some are talking about getting it down to mere
inches.

So the question is: If my Westbound Cessna at 6000 feet (with the
autopilot
keeping it happily on the GPS-track centerline) meets the descending
Bonanza
on the reciprocal track between the same two airports (using a similar
GPS/a-p combo), there is a distinct possibility that the horizontal
clearance may be zero...

...so is there anything in the current crop of GPS and/or Autopilot
systems
that allow me to maintain a small cross-track error of my choosing,
without
actually entering off-navaid-off-airport waypoints? ...or do we care;
am
I
overly concerned???

Bill Denton wrote:

I noticed the later posts referenced a set of "rules" for setting up the
"error", but absent those, you are back to the same old game of chance.
What's to prevent another pilot from picking a corresponding "error" that
would still maintain the head-on courses?


Presumably, they would both offset to the right, and I think the greatest
concern is about opposite direction traffic.

"Icebound" wrote in message ...
In the "good old" VOR days, it must have been pretty difficult to fly down
the centerline of an airway (or of any direct track).

So an eastbound VFR/IFR aircraft descending from 7500/7000 to his
destination, was more than likely to avoid traffic... on the reciprocal
track passing him by at 6500 or 6000... by some significant horizontal
error-distance, even if they didn't see each other (big sky theory :-) ).

GPS horizontal accuracy with WAAS is already in the order of magnitude of a
Cessna's wingspan, and some are talking about getting it down to mere
inches.

So the question is: If my Westbound Cessna at 6000 feet (with the autopilot
keeping it happily on the GPS-track centerline) meets the descending Bonanza
on the reciprocal track between the same two airports (using a similar
GPS/a-p combo), there is a distinct possibility that the horizontal
clearance may be zero...

...so is there anything in the current crop of GPS and/or Autopilot systems
that allow me to maintain a small cross-track error of my choosing, without
actually entering off-navaid-off-airport waypoints? ...or do we care; am I
overly concerned???

********************************************
Way overly concerned. I've been flying nearly 50 years, logged over
21,700 hours in general aviation, done a lot of IFR, without a lot of
GPS. I've not had any problems. As for the offset idea, what is to
prevent the other pilot from doing an offset that puts them directly
in your path? Whatever happened to eyeballs and watching out for
traffic?
As for being difficult to fly the VOR, it was/is no more difficult
than flying a compass heading and holding it.....which many pilots
seem unable to do anymore. They would prefer that electronic gadgets
do their flying for them and no thoughts as to what happens when the
electrodes take a vacation.
Ol Shy & Bashful - and unrepentant demanding grumpy old CFII