Garmin 430/530 Questions

[Steve Coleman]

Can you program in a radial off of a VOR to use as a GPS course?

For example, say your cleared from your present position to intercept a
given radial inbound. Up to this point you've been flying direct, or flying
a set of GPS waypoints. You're navigating off of GPS, not VOR. When this
happens to me, I always have to dial in the VOR freq. on the Garmin, set the
OBS to the proper radial and then switch the GPS from GPS navigation to VOR
navigation. In this situation, it's not too much of a problem and doesn't
really bother me. However, when I'm issued an IFR clearance that includes
an outbound radial on one VOR to an inbound radial on the next VOR it would
be nice to be able to program those into the flight plan. I haven't read
anything about it the manual and didn't think it was even possible until I
read an earlier post about a guy programming his flight plan into his Garmin
after an unusual IFR clearance (using radials).

Another similar question. Lets assume your being radar vectored on
departure, departure instructs you to intercept an airway to resume your own
navigation. What's the best way to intercept an airway with a 430? I've
been having to lookup the radial for the airway on the nearby VOR and then
enter into the Garmin to track inbound using VOR mode. It seems to me you
could easily enter the two VOR's or nav points that define the airway and
have the Garmin create a route overlying the airway. If you try this, you
end up with a route from your present position to the first VOR and then to
the second VOR. You don't end up with a route to intercept the airway
between the two VOR's. You could fly a manual course using GPS mode and
when you think your on the airway (by looking at the display on the Garmin)
you could hit direct to the second VOR. Doesn't seem ideal. There's got to
be a better way to do it?

[ArtP]

On Mon, 25 Aug 2003 20:38:57 -0600, "Steve Coleman"
> wrote:

>Can you program in a radial off of a VOR to use as a GPS course?

Do a direct to the VOR. Press OBS. Dial the desired radial. Fly the
desired intercept to the radial.

[paul k. sanchez]

>Can you program in a radial off of a VOR to use as a GPS course?
>
>For example, say your cleared from your present position to intercept a given
radial inbound. Up to this point you've been flying direct, or flying a set of
GPS waypoints. You're navigating off of GPS, not VOR. When this happens to
me, I always have to dial in the VOR freq. on the Garmin, set the OBS to the
proper radial and then switch the GPS from GPS navigation to VOR navigation.
In this situation, it's not too much of a problem and doesn't really bother me.
However, when I'm issued an IFR clearance that includes an outbound radial on
one VOR to an inbound radial on the next VOR it would be nice to be able to
program those into the flight plan. I haven't read anything about it the
manual and didn't think it was even possible until I read an earlier post about
a guy programming his flight plan into his Garmin after an unusual IFR
clearance (using radials).
>
>Another similar question. Lets assume your being radar vectored on departure,
departure instructs you to intercept an airway to resume your own navigation.
What's the best way to intercept an airway with a 430? I've been having to
lookup the radial for the airway on the nearby VOR and then enter into the
Garmin to track inbound using VOR mode. It seems to me you could easily enter
the two VOR's or nav points that define the airway and have the Garmin create a
route overlying the airway. If you try this, you end up with a route from your
present position to the first VOR and then to the second VOR. You don't end
up with a route to intercept the airway between the two VOR's. You could fly a
manual course using GPS mode and when you think your on the airway (by looking
at the display on the Garmin) you could hit direct to the second VOR. Doesn't
seem ideal. There's got to be a better way to do it?
>

Steve:
Me thinks you have not really learned the software or the benefit of flight
plans. If you were told to fly the XYZ vor 180 radial inbound, thence join V123
as filed. What would be wrong with having the airway in your flight plan,
select the XYZ vor as your current waypoint either thru the flight plan page or
the FPL box after you press DIRECT. Then move the cursor down to the course box
and dial in 360. You're done. You have defined a 360 course line to the XYZ
vor, then resume the flight plan.

In your second problem (or misunderstanding) I would suggest bring the cursor
down to the waypoint you want on the flight plan, press DIRECT twice which
tells the Garmin 400/500 series that you want to fly the leg XYZ-ABC. Again
problem solved.

What instructor did your training on the Garmin 400/500 series? That would be
my question. I think you have not been taught the concept of using the DIRECT
button to define course lines nor how to activate selected legs on your flight
plan. A very convenient feature to master if you are doing GPS approaches.

I would strongly suggest that you evaluate the quality of your training on the
Garmin 400/500 series.


paul k. sanchez, cfii-mei
on eagles’ wings
2011 south perimeter road, suite g
fort lauderdale, florida 33309-7135
305-389-1742 wireless
954-776-0527 fax
954-965-8329 home/fax

[Steve Coleman]

Thaks for the info, that works great if that VOR is your next waypoint, but
what if the radial you want to use is two or even three waypoints away?
i.e. you're in the runup area programming your IFR clearance before
departure.

"ArtP" > wrote in message
...
> On Mon, 25 Aug 2003 20:38:57 -0600, "Steve Coleman"
> > wrote:
>
> >Can you program in a radial off of a VOR to use as a GPS course?
>
> Do a direct to the VOR. Press OBS. Dial the desired radial. Fly the
> desired intercept to the radial.

[ArtP]

On Mon, 25 Aug 2003 21:39:43 -0600, "Steve Coleman"
> wrote:

>Thaks for the info, that works great if that VOR is your next waypoint, but
>what if the radial you want to use is two or even three waypoints away?
>i.e. you're in the runup area programming your IFR clearance before
>departure.

You could create a user waypoint at the intersection of the 2 VOR
radials. But I have never seen a clearance where that intersection was
not already named.

[ArtP]

On Tue, 26 Aug 2003 00:31:34 -0600, "Steve Coleman"
> wrote:

>
>If I understand your statement below, you're suggesting there is an
>intersection where these two VOR's intercept on the given radials. If that
>were the case, you'd program TCH (wasatch VOR), XYZ intersection (whatever
>intersection is "supposed" to exist) and MLF (milford VOR) like a normal
>route, but since this intersection doesn't exist (which I'm assuming since
>they don't give it to you in your clearance) you can't do that. Granted
>this is a rare circumstance, but I have seen situations simlar to this.

In which case creating a user waypoint (which is more trouble than it
is worth) is the only I can think of that you could program the route
in advance.

[[email protected]]

Without going into your particulars, as a general statement the only accurate
way to fly an airway is by creating a flight plan with the VOR stations as
waypoints and any turn-point named fix at a minimum included into the airway
flight plan.

Using the OBS mode, although fine for short distances, introduces errors of
magnetic variation tables in the 430, and possible declination adjustments to
the station unknown to Garmin.

Steve Coleman wrote:

> Can you program in a radial off of a VOR to use as a GPS course?
>
> For example, say your cleared from your present position to intercept a
> given radial inbound. Up to this point you've been flying direct, or flying
> a set of GPS waypoints. You're navigating off of GPS, not VOR. When this
> happens to me, I always have to dial in the VOR freq. on the Garmin, set the
> OBS to the proper radial and then switch the GPS from GPS navigation to VOR
> navigation. In this situation, it's not too much of a problem and doesn't
> really bother me. However, when I'm issued an IFR clearance that includes
> an outbound radial on one VOR to an inbound radial on the next VOR it would
> be nice to be able to program those into the flight plan. I haven't read
> anything about it the manual and didn't think it was even possible until I
> read an earlier post about a guy programming his flight plan into his Garmin
> after an unusual IFR clearance (using radials).
>
> Another similar question. Lets assume your being radar vectored on
> departure, departure instructs you to intercept an airway to resume your own
> navigation. What's the best way to intercept an airway with a 430? I've
> been having to lookup the radial for the airway on the nearby VOR and then
> enter into the Garmin to track inbound using VOR mode. It seems to me you
> could easily enter the two VOR's or nav points that define the airway and
> have the Garmin create a route overlying the airway. If you try this, you
> end up with a route from your present position to the first VOR and then to
> the second VOR. You don't end up with a route to intercept the airway
> between the two VOR's. You could fly a manual course using GPS mode and
> when you think your on the airway (by looking at the display on the Garmin)
> you could hit direct to the second VOR. Doesn't seem ideal. There's got to
> be a better way to do it?

[John Bell]

> clear to xyz airport, salt lake 8 depature, wasatch 175 radial to
intercept
> milford 355 radial. Salt Lake 8 departure is a radar vector departure and
> typically the actual clearance is irrelevant because departure radar
vectors
> you and when they hand you off to center, center clears you direct further
> down the line. However, if you actually had to fly this clearance, how
> would you program it in the flight plan of the garmin and fly it without
> having to tune the two different VOR's?
>

The first thing that I would look at is the departure plate. Very seldom
have I seen ATC assign random radials. If you look on a chart, are these
the charted radials between Wasatch and Milford? If this is the case then
you could program Wasatch to Milford and intercept the route.

If this was some oddball intersection not on a line between two VOR radials,
then you could create a user point. For example if you had the ABC 135
radial to the DEF 045 radial, you could create a route from ABC to the user
point created from the ABC 135 and DEF 045 to DEF. The 430 allows you to
create a user waypoint from two radials. I have not had the chance to check
if the 430.

Check out the chapter on route modifications in my online book at
www.cockpitgps.com. Let me know if that helps.

John Bell
www.cockpitgps.com

[Dave Butler]

John Bell wrote:

> The Garmin 196, 295, 400, and 500 series appear to correct for this
> variation problem when the VOR is the active waypoint. The GPS III Pilot
> does not.
>
> The problem is that the VOR is aligned to magnetic north, but is not
> realigned as the magnetic variation changes over time. Thus, this is really
> a VOR problem. However, the GPS receivers that I mention compensate for
> this.

Do you mean to say they compensate for the lack of realignment by using the
navaid's published "declination" instead of the actual alignment of magnetic
north? I am skeptical.

My understanding is they use an approximation like a best-fit polynomial or
similar to derive the magnetic declination at any given location.

Dave

Remove SHIRT to reply directly.

[JerryK]

I flew something like this a few weeks ago leaving Ogden. I programmed in a
leg from some waypoint (I don't remember which one) to a VOR (Milford?) I
then flew until I intercepted radial off Wasatch using OBS mode. When I
intercepted appropriate leg I pressed enter and made the leg the active leg.

jerry

[John Bell]

> Do you mean to say they compensate for the lack of realignment by using
the
> navaid's published "declination" instead of the actual alignment of
magnetic
> north? I am skeptical.
>
> My understanding is they use an approximation like a best-fit polynomial
or
> similar to derive the magnetic declination at any given location.

Dave,

From what I can tell through experimentation with the Garmin 196, GPS 400
simulator, and 295 it appears that these GPS receivers use the navaid's
published variation instead of the approximation that you mention second.
The GPS III Pilot does not use the published variation.

If you want to do some experimentation, use SWL (Snow Hill on the east coast
of Maryland). Try the OBS mode and notice that it does not match the COURSE
or DTK. Try creating a user waypoint at the same point and you will notice
that the OBS mode works differently.

I have an example in my book on page 138 of the .pdf file under
Miscellaneous. It is page 9-14 of the printed copy.

I am always open to corrections.

John
www.cockpitgps.com

[[email protected]]

>
>
> The problem is that the VOR is aligned to magnetic north, but is not
> realigned as the magnetic variation changes over time. Thus, this is really
> a VOR problem. However, the GPS receivers that I mention compensate for
> this.
>

I often see 2 or 3 degrees difference between the Garmin 530's desired track
along an IAP segment, and that on the approach chart. Of course, it doesn't
matter since the IAP string is a flight plan between waypoints.

I know the FAA folks who publish the IAPs consider the magnetic courses they
show on the official IAP document to be "guidelines," rather than the precise
magnetic bearing between IAP waypoints.

[Dave Butler]

John Bell wrote:
>>Do you mean to say they compensate for the lack of realignment by using
>
> the
>
>>navaid's published "declination" instead of the actual alignment of
>
> magnetic
>
>>north? I am skeptical.
>>
>>My understanding is they use an approximation like a best-fit polynomial
>
> or
>
>>similar to derive the magnetic declination at any given location.
>
>
> Dave,
>
> From what I can tell through experimentation with the Garmin 196, GPS 400
> simulator, and 295 it appears that these GPS receivers use the navaid's
> published variation instead of the approximation that you mention second.
> The GPS III Pilot does not use the published variation.
>
> If you want to do some experimentation, use SWL (Snow Hill on the east coast
> of Maryland). Try the OBS mode and notice that it does not match the COURSE
> or DTK. Try creating a user waypoint at the same point and you will notice
> that the OBS mode works differently.
>
> I have an example in my book on page 138 of the .pdf file under
> Miscellaneous. It is page 9-14 of the printed copy.
>
> I am always open to corrections.

There is a thread "VOR versus GPS" on rec.aviation.ifr where this is discussed
at some length. I remembered Julian Scarfe's comments about how this method of
operation raises some interesting inconsistencies, including the bahavior you
note above, where the bearing to the station (using published declination) does
not match the desired track to the station (using interpolated declination). I
had forgotten that the consensus was that's the way it works, with the
aforementioned inconsistencies. You're right. I'm wrong. Thanks.

Dave

Remove SHIRT to reply directly.

[[email protected]]

Ron Natalie wrote:

> > wrote in message ...
> >
> > I often see 2 or 3 degrees difference between the Garmin 530's desired track
> > along an IAP segment, and that on the approach chart. Of course, it doesn't
> > matter since the IAP string is a flight plan between waypoints.
>
> That's to be expected. Even if there were no magnetic variation, the track
> (except in certain degenerate cases) must change as you fly along any straight
> line.
>

Not for a 5 or 10 mile IAP segment.

>
> > I know the FAA folks who publish the IAPs consider the magnetic courses they
> > show on the official IAP document to be "guidelines," rather than the precise
> > magnetic bearing between IAP waypoints.
>
> Nope, they're pretty danged accurate. You just have to realize that the bearing
> relative to a station must change while tracking a straight line.

Then, why are the chart and the Garmin often in disagreement for a 5 to 10 mile IAP
segment?

[Ron Natalie]

> wrote in message ...

> Then, why are the chart and the Garmin often in disagreement for a 5 to 10 mile IAP
> segment?
>
OK, you got me, it may very well be wrong for the IAP. The final is smack on. I misread
the earlier post.

[[email protected]]

Dave Butler wrote:

> wrote:
> >
> > Ron Natalie wrote:
> >
> >
> > wrote in message ...
> >>
> >>>I often see 2 or 3 degrees difference between the Garmin 530's desired track
> >>>along an IAP segment, and that on the approach chart. Of course, it doesn't
> >>>matter since the IAP string is a flight plan between waypoints.
> >>
> >>That's to be expected. Even if there were no magnetic variation, the track
> >>(except in certain degenerate cases) must change as you fly along any straight
> >>line.
> >>
> >
> >
> > Not for a 5 or 10 mile IAP segment.
> >
> >
> >>>I know the FAA folks who publish the IAPs consider the magnetic courses they
> >>>show on the official IAP document to be "guidelines," rather than the precise
> >>>magnetic bearing between IAP waypoints.
> >>
> >>Nope, they're pretty danged accurate. You just have to realize that the bearing
> >>relative to a station must change while tracking a straight line.
> >
> >
> > Then, why are the chart and the Garmin often in disagreement for a 5 to 10 mile IAP
> > segment?
>
> Well, it might be that they are using different values for the local magnetic
> declination. For example, suppose NACO uses a measured declination from an FAA
> check flight, and Garmin uses a calculated value from a best-fit polynomial.
>
>

Exactly, as I said earlier in the thread.

[Andrew Gideon]

Steve Coleman wrote:

> I can't remember the exact clearance, but I frequently get a clearance
> something like this departing Salt Lake, southbound.

It happens around the CMK VOR too, for (if memory serves) westbound traffic.
I'd guess they reorganized traffic flow at some point recently, and have
yet to add the intersection of the two relevant radials as a waypoint.

Presumably, this'll happen at some point.

- Andrew