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

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?

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?





"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:

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?

In the US and outside of class B airspace, it is the pilot, not ATC, who
is ultimately responsible for IFR/VFR traffic separation. A VFR traffic
advisory to an IFR aircraft is a courtesy offered by ATC; it is not a
guarantee.

--
Peter

"Peter R." wrote in message
...
Bill Denton ) wrote:

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?

In the US and outside of class B airspace, it is the pilot, not ATC, who
is ultimately responsible for IFR/VFR traffic separation. A VFR traffic
advisory to an IFR aircraft is a courtesy offered by ATC; it is not a
guarantee.

--
Peter

You might want to rethink your reply.

A pilot in clouds or other IMC cannot provide separation to any traffic he
cannot see.

Bill Denton ) wrote:

You might want to rethink your reply

Easy there, Bill. There is no need for that.

A pilot in clouds or other IMC cannot provide separation to any traffic he
cannot see.

I am discussing IFR/VFR separation, not IFR/IFR separation. Hopefully,
no VFR aircraft will be in IMC, but that point is irrelevant since most
times ATC does not know if it is IMC or VMC; they only have blips on
their screen.

Consider this: It is quite possible that a) a VFR aircraft is climbing
or descending through an IFR aircraft's cruise altitude, or b) an IFR
cruise altitude is below 3,000 AGL, which means that a VFR aircraft
could be at any altitude 3,000 feet AGL or below s/he desires, including
that IFR aircraft's altitude.

Will ATC provide traffic callouts and or vectors around VFR traffic in
either scenario above? Most likely. Are US controllers required to?
Outside of class B airspace, the answer is no.

--
Peter

"Bill Denton" wrote in
:


"Peter R." wrote in message
...
Bill Denton ) wrote:

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?

In the US and outside of class B airspace, it is the pilot, not ATC,
who is ultimately responsible for IFR/VFR traffic separation. A VFR
traffic advisory to an IFR aircraft is a courtesy offered by ATC; it
is not a guarantee.

--
Peter

You might want to rethink your reply.

A pilot in clouds or other IMC cannot provide separation to any traffic
he cannot see.



Neither can ATC - for example, when there is no Radar Coverage.

The system is designed to work even in those conditions, and the rules
follow suit...

In VMC, ALL pilots are required to "see and avoid", VFR or IFR.

VFR pilots are supposed to stay out of IMC to prevent getting hit by IFR
pilots on IFR flight plans in the IMC.

When there is no Radar, IFR separation is done using spacing and reporting
points. There are no traffic advisories, IFR or VFR.

VFR-to-IFR separation is a courtesy, as Peter said. If ATC calls out a
target to an IFR flight, and they are not talking to the VFR target too,
they can't even provide instructions that guarantee safe avoidance...


Don't take your advisories for granted. They are a favor.

I had a minute so I looked this up; you misread the AIM.

4-4-10. IFR SEPARATION STANDARDS

b. Separation will be provided (by ATC - my note) between all aircraft
operating on IFR flight plans except during that part of the flight (outside
of Class B airspace or a TRSA) being conducted on a VFR-on-top/VFR
conditions clearance. Under these conditions, ATC may issue traffic
advisories, but it is the sole responsibility of the pilot to be vigilant so
as to see and avoid other aircraft.

To paraphrase and clarify: If you are "outside of Class B airspace or a
TRSA" and flying on a "VFR-on-top/VFR conditions clearance", "ATC may issue
traffic advisories, but it is the sole responsibility of the pilot to be
vigilant so as to see and avoid other aircraft". Otherwise, "Separation will
be provided (by ATC - my note) between all aircraft operating on IFR flight
plans".




"Peter R." wrote in message
...
Bill Denton ) wrote:

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?

In the US and outside of class B airspace, it is the pilot, not ATC, who
is ultimately responsible for IFR/VFR traffic separation. A VFR traffic
advisory to an IFR aircraft is a courtesy offered by ATC; it is not a
guarantee.

--
Peter

Bill Denton ) wrote:

I had a minute so I looked this up; you misread the AIM.

You and I have been through this before. The AIM is not regulatory and
perhaps you might want to re-read that passage. It appears to me that
you have misinterpreted it.

Let's break this down:

b. Separation will be provided (by ATC - my note) between all aircraft
operating on IFR flight plans except during that part of the flight (outside
of Class B airspace or a TRSA) being conducted on a VFR-on-top/VFR
conditions clearance.

Please show me where in that passage above does it say anything about
IFR aircraft being separated from VFR aircraft. Note the operative
word "between" being used there. I interpret the passage to be
discussing IFR aircraft being separated from IFR aircraft.

To paraphrase and clarify: If you are "outside of Class B airspace or a
TRSA" and flying on a "VFR-on-top/VFR conditions clearance", "ATC may issue
traffic advisories, but it is the sole responsibility of the pilot to be
vigilant so as to see and avoid other aircraft". Otherwise, "Separation will
be provided (by ATC - my note) between all aircraft operating on IFR flight
plans".

There, you stated it, too. "BETWEEN all aircraft operating on IFR
flight plans." Where does it say anything about ATC's responsibility
about separation between those aircraft on IFR flight plans and those on
VFR flight plans? Not in that passage it doesn't.



--
Peter

My comments in text:



"Peter R." wrote in message
...
Bill Denton ) wrote:

I had a minute so I looked this up; you misread the AIM.

You and I have been through this before. The AIM is not regulatory and
perhaps you might want to re-read that passage. It appears to me that
you have misinterpreted it.

Regulatory/no-regulatory is immaterial. This portion of the AIM simply
states what services will be offered to pilots by ATC.




Let's break this down:

b. Separation will be provided (by ATC - my note) between all aircraft
operating on IFR flight plans except during that part of the flight
(outside
of Class B airspace or a TRSA) being conducted on a VFR-on-top/VFR
conditions clearance.

Please show me where in that passage above does it say anything about
IFR aircraft being separated from VFR aircraft. Note the operative
word "between" being used there. I interpret the passage to be
discussing IFR aircraft being separated from IFR aircraft.

The separation of VFR/IFR aircraft is not covered in this section; the
separation of ALL aircraft is discussed in the previous section.

The purpose of this section is to remind VFR-on-top-pilots that while they
are on an IFR flight plan, ATC has allowed them to deviate and fly under VFR
rules (including see and avoid) and that ATC is not obligated to provide
traffic guidance.



To paraphrase and clarify: If you are "outside of Class B airspace or a
TRSA" and flying on a "VFR-on-top/VFR conditions clearance", "ATC may
issue
traffic advisories, but it is the sole responsibility of the pilot to be
vigilant so as to see and avoid other aircraft". Otherwise, "Separation
will
be provided (by ATC - my note) between all aircraft operating on IFR
flight
plans".

There, you stated it, too. "BETWEEN all aircraft operating on IFR
flight plans." Where does it say anything about ATC's responsibility
about separation between those aircraft on IFR flight plans and those on
VFR flight plans? Not in that passage it doesn't.

As I stated above, VFR-on-top operations are conducted on IFR flight plans
and the purpose of this section is to explain the services to be provided or
not provided by ATC to VFR-on-top pilots.






--
Peter

== Peter R writes:

Bill Denton ) wrote:
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?

In the US and outside of class B airspace, it is the pilot, not ATC, who
is ultimately responsible for IFR/VFR traffic separation. A VFR traffic
advisory to an IFR aircraft is a courtesy offered by ATC; it is not a
guarantee.

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

dan.

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

No, separation is not provided by ATC.




"Dan Girellini" wrote in message
...
== Peter R writes:

Bill Denton ) wrote:
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?

In the US and outside of class B airspace, it is the pilot, not ATC,
who
is ultimately responsible for IFR/VFR traffic separation. A VFR
traffic
advisory to an IFR aircraft is a courtesy offered by ATC; it is not a
guarantee.

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

dan.

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