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

"Icebound" wrote in message
...
[...]
...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?

You are not overly concerned, it does present a greater chance of a
collision.

I haven't heard of a GPS unit that allows the user to set some sort of
"offset" from a course to follow, but it wouldn't surprise if such a feature
did exist somewhere.

Beyond that, the "big sky theory" still works reasonably well. Two
airplanes in level flight on opposite headings on the same airway stand a
decently improved chance of running into each other if they are using GPS.
But when at least one is climbing, they share their altitude for such a
short period of time, I would think that the *actual* risk is relatively
low, even if the GPS does significantly increase the risk when compared to a
VOR receiver.

In any case, even before GPS it was still reasonably important to be alert
for other traffic while traveling on airways (even beyond the general
importance of doing so at all times). GPS increases the risk, but the risk
was always there and I've certainly had my share of close encounters (under
1 mile) flying on airways with a VOR receiver.

Pete

"Peter Duniho" wrote:
I haven't heard of a GPS unit that allows the user to set some sort of
"offset" from a course to follow, but it wouldn't surprise if such a feature
did exist somewhere.

The CNX-80 / GNS-480 has it. It's called "Parallel Track". You tell it
if you want to fly left or right of course and by how much (in 1/10's of
a mile IIRC), and it invents a new course line for you to follow.

I believe the Apollo GX-60 had it too. The story I heard was the CAP
wanted to buy a bunch of GX-60's, but insisted Apollo add the Parallel
Track feature to facilitate flying grid search patterns.

"Peter Duniho" wrote:
I haven't heard of a GPS unit that allows the user to set some sort of
"offset" from a course to follow, but it wouldn't surprise if such a
feature
did exist somewhere.

The CNX-80 / GNS-480 has it. It's called "Parallel Track". You tell it
if you want to fly left or right of course and by how much (in 1/10's of
a mile IIRC), and it invents a new course line for you to follow.

I believe the Apollo GX-60 had it too. The story I heard was the CAP
wanted to buy a bunch of GX-60's, but insisted Apollo add the Parallel
Track feature to facilitate flying grid search patterns.

Parallel track and the grid search feature are not related to each other.
The GX series has the search grid lines on its display so CAP pilots can
stay oriented in their search grid. But even that wasn't as useful because
the grid lines they did show were not at the correct level. IIRC, you want
7.5 minute grid lines and the GX only showed down to 15 minute grid lines.

Roy Smith wrote in
:

"Peter Duniho" wrote:
I haven't heard of a GPS unit that allows the user to set some sort
of "offset" from a course to follow, but it wouldn't surprise if such
a feature did exist somewhere.

The CNX-80 / GNS-480 has it. It's called "Parallel Track". You tell
it if you want to fly left or right of course and by how much (in
1/10's of a mile IIRC), and it invents a new course line for you to
follow.

The Trimble 2102 has it, and so do most other units.

--
Regards,

Stan

Stan Gosnell wrote:

The Trimble 2102 has it, and so do most other units.


Do you know whether the Garmin 400/500 series (other than the 480) have it?

[how and whether to fly an offset on a GPS track]

Just hand fly. You can hand fly any offset you like.

Jose
--
Freedom. It seemed like a good idea at the time.
for Email, make the obvious change in the address.

"Peter Duniho" wrote in message
...
I haven't heard of a GPS unit that allows the user to set some sort of
"offset" from a course to follow, but it wouldn't surprise if such a
feature did exist somewhere.


My Northstar M3 has parallel track offset, as does the GX-60