garmin 296

For years I've turned by back on Garmin GPSs because they did not
provide terrain. Now it looks like the Garmin 296 provides that. I'm
considering selling my Skymap IIIc (which has terrain) and buying the
Garmin. The IIIc certainly has a bigger screen but the Garmin has the
partial panel turn coordinator and IAF vectors for approaches.
However, I was really, really surprised to see that Garmin is missing
Victor airways. I can't tell you how useful that has been while being
rapid fire assigned airways near L.A. or anywhere. Being able to just
put the course line on the airway line made flying airways simple.
Garmin says they don't have plans to fix this. Too bad, having airways
really would make it a better unit (and prevent frequent grabs for the
enroute chart). Its also great for VFR pilots who want to practice
steep turns and stalls but want to ensure they are the minimum 4 miles
from an airway.

-Robert

An article (actually, a sidebar to an article) in the July IFR magazine says
"According to AIM 1-1-20 (f)(7), by omission, you can't just input the VOR
as the active waypoint....," and "...according to this passage, the FAA
allows GPS to substitute for everything except for a VOR. For some reason,
the FAA has faith in its VORs and won't let you substitute GPS for them as a
primary means of navigation."

Maybe this is why Garmin does not include VOR-based airways.

Bob Gardner

"Robert M. Gary" wrote in message
om...
For years I've turned by back on Garmin GPSs because they did not
provide terrain. Now it looks like the Garmin 296 provides that. I'm
considering selling my Skymap IIIc (which has terrain) and buying the
Garmin. The IIIc certainly has a bigger screen but the Garmin has the
partial panel turn coordinator and IAF vectors for approaches.
However, I was really, really surprised to see that Garmin is missing
Victor airways. I can't tell you how useful that has been while being
rapid fire assigned airways near L.A. or anywhere. Being able to just
put the course line on the airway line made flying airways simple.
Garmin says they don't have plans to fix this. Too bad, having airways
really would make it a better unit (and prevent frequent grabs for the
enroute chart). Its also great for VFR pilots who want to practice
steep turns and stalls but want to ensure they are the minimum 4 miles
from an airway.

-Robert

In article , Bob Gardner
wrote:

An article (actually, a sidebar to an article) in the July IFR magazine says
"According to AIM 1-1-20 (f)(7), by omission, you can't just input the VOR
as the active waypoint....," and "...according to this passage, the FAA
allows GPS to substitute for everything except for a VOR. For some reason,
the FAA has faith in its VORs and won't let you substitute GPS for them as a
primary means of navigation."
Maybe this is why Garmin does not include VOR-based airways.

Not to mention the software updates required to keep the airways
current.

I have yet to try this myself, but two pilots I know suggested I try it.
The airways are defined by VOR radials. GPSs do not seem to navigate them
correctly. In fact, one of the pilots mentioned flew with an "instructor"
who was relying on a GPS for lateral guidance on an IFR flight plan. The
pilot told the instructor to knock it off and use the vors as he was seeing
CDI needle deflection. The instructor said not to worry.

After some time ATC informed them that they were off the airway (though the
gps showed dead-on).

The instructor got a smack in the head.

Airways and intersections are quite simple to fly, why the obsession with
GPS?

"Bob Gardner" wrote in message
...
An article (actually, a sidebar to an article) in the July IFR magazine
says
"According to AIM 1-1-20 (f)(7), by omission, you can't just input the VOR
as the active waypoint....," and "...according to this passage, the FAA
allows GPS to substitute for everything except for a VOR. For some reason,
the FAA has faith in its VORs and won't let you substitute GPS for them as
a
primary means of navigation."

Maybe this is why Garmin does not include VOR-based airways.

Bob Gardner

"Robert M. Gary" wrote in message
om...
For years I've turned by back on Garmin GPSs because they did not
provide terrain. Now it looks like the Garmin 296 provides that. I'm
considering selling my Skymap IIIc (which has terrain) and buying the
Garmin. The IIIc certainly has a bigger screen but the Garmin has the
partial panel turn coordinator and IAF vectors for approaches.
However, I was really, really surprised to see that Garmin is missing
Victor airways. I can't tell you how useful that has been while being
rapid fire assigned airways near L.A. or anywhere. Being able to just
put the course line on the airway line made flying airways simple.
Garmin says they don't have plans to fix this. Too bad, having airways
really would make it a better unit (and prevent frequent grabs for the
enroute chart). Its also great for VFR pilots who want to practice
steep turns and stalls but want to ensure they are the minimum 4 miles
from an airway.

-Robert

But today my SkymapIIIc has airways. They are pink on the display. You
just put your white course line on the pink airway line and you're
flying down the middle of the airway. No need to figure out what VORs
or intersections are on the airway when ATC puts you on an airway.
Often, near SoCal they don't even name intersections. You'll get
instructions from approach like, "Victor 123 to Victor 234 to Victor
345, etc, etc". I've gotten as many as 5 victor airways in my
clearance as I approached SoCal, none of which included intersections
in the clearance. The SkymapIIIC sure made it easier. However, I just
bought the 296 because of the turn coordinator functionality (for
emergency partial panels no electrical and no vac) and for the battery
life after loss of power.

-Robert


"Bob Gardner" wrote in message ...
An article (actually, a sidebar to an article) in the July IFR magazine says
"According to AIM 1-1-20 (f)(7), by omission, you can't just input the VOR
as the active waypoint....," and "...according to this passage, the FAA
allows GPS to substitute for everything except for a VOR. For some reason,
the FAA has faith in its VORs and won't let you substitute GPS for them as a
primary means of navigation."

Maybe this is why Garmin does not include VOR-based airways.

Bob Gardner

"Robert M. Gary" wrote in message
om...
For years I've turned by back on Garmin GPSs because they did not
provide terrain. Now it looks like the Garmin 296 provides that. I'm
considering selling my Skymap IIIc (which has terrain) and buying the
Garmin. The IIIc certainly has a bigger screen but the Garmin has the
partial panel turn coordinator and IAF vectors for approaches.
However, I was really, really surprised to see that Garmin is missing
Victor airways. I can't tell you how useful that has been while being
rapid fire assigned airways near L.A. or anywhere. Being able to just
put the course line on the airway line made flying airways simple.
Garmin says they don't have plans to fix this. Too bad, having airways
really would make it a better unit (and prevent frequent grabs for the
enroute chart). Its also great for VFR pilots who want to practice
steep turns and stalls but want to ensure they are the minimum 4 miles
from an airway.

-Robert

From: "Richard Hertz"


I have yet to try this myself, but two pilots I know suggested I try it.
The airways are defined by VOR radials. GPSs do not seem to navigate them
correctly. In fact, one of the pilots mentioned flew with an
"instructor"
who was relying on a GPS for lateral guidance on an IFR flight plan. The
pilot told the instructor to knock it off and use the vors as he was
seeing
CDI needle deflection. The instructor said not to worry.

After some time ATC informed them that they were off the airway (though
the
gps showed dead-on).

You should be able to navigate an airway more accurately using a GPS than
you can with a VOR.

The problem with VORs is that they are not aligned with magnetic north.
Usually, they are aligned with magnetic north when the VOR station is first
installed, but they are not kept in alignment as the earth's magnetic field
shifts. Have you ever noticed how runways are occasionally recharted with
new magnetic headings? Also check he
http://www.geolab.nrcan.gc.ca/geomag...vt_nmp_e.shtml.

Many GPS receivers use a model of the earth's magnetic field that results in
a magnetic correction similar to the isogonic lines on the chart. If the
instructor executed a direct to the VOR waypoint in the GPS and then used
the OBS feature to select the inbound course as depicted by the VOR radial
on the chart, he may be several degrees off.

If you want to look at an example, go to www.airnav.com and pull up SWL VOR
and KOXB (Ocean City). SWL has a variation of 8W (1965) and KOXB has a
variation of 12W (2000). There might be a close airport, but SWL is 22 nm
from KOXB.

Some GPS receivers such as the Garmin 196, 295, 296, 430, and 530 use the
slaved value of the VOR for the OBS mode. Thus, setting the OBS mode to a
value results in the same path over the ground as if you selected the VOR
OBS to the same number. On some GPS receivers, such as the Garmin GPS III
Pilot the GPS does not compensate for this VOR misalignment.

What I don't know is whether there is any requirement for an IFR certified
GPS to use the VOR slaved value for magnetic variation. There is also the
possibility that the instructor in your story was using a non-IFR GPS.

This is not to say the OBS mode is the best way to navigate an airway, just
that this might be a cause for error. A better way is to set up a route in
the GPS to reflect points on the airway. Such as from VOR A to VOR B or
INTERSECTION to VOR if there is a bend in the airway.

John Bell
www.cockpitgps.com

"Bob Gardner" wrote in message
...
An article (actually, a sidebar to an article) in the July IFR magazine
says
"According to AIM 1-1-20 (f)(7), by omission, you can't just input the VOR
as the active waypoint....," and "...according to this passage, the FAA
allows GPS to substitute for everything except for a VOR. For some reason,
the FAA has faith in its VORs and won't let you substitute GPS for them as
a
primary means of navigation."

Maybe this is why Garmin does not include VOR-based airways.


Garmin panel mount units have airways.

More likely the reason airways are not included in the handhelds is the
limitation on memory for the database.

"Richard Hertz" wrote in message
...
I have yet to try this myself, but two pilots I know suggested I try it.
The airways are defined by VOR radials. GPSs do not seem to navigate them
correctly. In fact, one of the pilots mentioned flew with an
"instructor"
who was relying on a GPS for lateral guidance on an IFR flight plan. The
pilot told the instructor to knock it off and use the vors as he was
seeing
CDI needle deflection. The instructor said not to worry.

After some time ATC informed them that they were off the airway (though
the
gps showed dead-on).


If the GPS is programmed properly it will follow airways just fine. Usually
in a case like this whoever put the flight plan into the GPS left out some
intermediate waypoint.

VOR's rarely agree with each other as closely as the GPS follows the
airways. If the GPS is properly set up it will rarely be more than a degree
off the airway, while the VORs can be as much as six degrees off. The GPS
sets up a single course for the entire length of the route segment, while
published airways may not have a single magnetic course for the route
segment due to change in magnetic variation. This is why the GPS is usually
a degree off what the published airway information is. If following the GPS
gets you so far off that ATC brings it to your attention, you probably
entered some bad data into the flight plan in the GPS.

On Tue, 15 Jun 2004 15:52:56 -0700, "Bob Gardner"
wrote:

An article (actually, a sidebar to an article) in the July IFR magazine says
"According to AIM 1-1-20 (f)(7), by omission, you can't just input the VOR
as the active waypoint....," and "...according to this passage, the FAA
allows GPS to substitute for everything except for a VOR. For some reason,
the FAA has faith in its VORs and won't let you substitute GPS for them as a
primary means of navigation."

Bob,

I cannot find that paragraph.

AIM 1-1-20 refers to WAAS boxes certified under TSO-146, which do not
require any other type of navigation equipment to be on board and can be
used for enroute navigation using VOR's (and airways, for that matter),
without a VOR receiver on board.

You (or the July IFR magazine -- haven't seen it yet) are probably (or
should be) referencing 1-1-19 which refers to TSO 129 boxes. Those do
require an alternate means of navigation to be on board.

But, not having read the article, I would disagree that one cannot use
VOR's as the active waypoint in a TSO129 box that is approved for GPS
approaches. It makes no sense so long as the VOR is retrieved from the
box's database. Since that same box can be used to fly overlay approaches
based on a VOR, to claim that because the substitution is omitted in 1-1-19
(f)(7) that it is not allowed, makes no sense. It is certainly allowed in
performing the overlay approaches.


Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

"John Bell" wrote in message . com...
From: "Richard Hertz"


I have yet to try this myself, but two pilots I know suggested I try it.
The airways are defined by VOR radials. GPSs do not seem to navigate them
correctly. In fact, one of the pilots mentioned flew with an
"instructor"
who was relying on a GPS for lateral guidance on an IFR flight plan. The
pilot told the instructor to knock it off and use the vors as he was
seeing
CDI needle deflection. The instructor said not to worry.

After some time ATC informed them that they were off the airway (though
the
gps showed dead-on).

You should be able to navigate an airway more accurately using a GPS than
you can with a VOR.

I think so too. I never had any trouble following airways with my
Skymap IIIc. I recently spoke with some C-5 pilots who claim they can
tell who is flying on GPS by looking at how close they are to the
center of the airway. The GPS takes all the work out of trying to find
your wind correction angle on the airway. Just put the white line on
the pink line (in the case of my Skymap).

-Robert