GPS clearance puzzle

[Roy Smith]

Apparently, if you file IFR HPN -> MMU, you get a clearance which starts
"CMK CMK275R SAX039R SAX" (i.e. fly outbound on the CMK 275 until you
intercept the SAX 039, then fly that inbound to SAX). In the good old
days of 2 VOR receivers, this is trivial to fly; the radios don't know
or care that the cross-radial fix you're going to doesn't have a name.
But, how would you fly that with a GPS?

I've been puzzling over that one for a week or so now, and the best I
can come up with is to use the GPS's OBS mode to track outbound on the
CMK 275, and set up a VOR receiver to indicate the crossing radial.

Can anybody figure out a way to set it up purely on the GPS? I'm using
a CNX-80, but it might be interesting to see how other units would do it
too.

[Andrew Gideon]

Roy Smith wrote:

> Apparently, if you file IFR HPN -> MMU, you get a clearance which starts
> "CMK CMK275R SAX039R SAX" (i.e. fly outbound on the CMK 275 until you
> intercept the SAX 039, then fly that inbound to SAX).

Interesting. I flew from BVY to CDW this past Monday. My clearance ended

... CMK V? SAX Direct

As I was approaching the CMK VOR, I was told to depart on the 275 radial.
When I acknowledged that, I was told: "Oh, let's make this easy" and was
told to follow the airway to SAX (I forget which V that was at the moment).

The difference between the airway and the 275R is pretty slight. Extra room
for EWR or TEB departures (the wind was from the northeast)? Something
else?

Either way, I appreciated sticking with the airway. It saved me from having
to find the CDI button on the 430 <grin>.

- Andrew

[Steven P. McNicoll]

"Roy Smith" > wrote in message
...
>
> Apparently, if you file IFR HPN -> MMU, you get a clearance which starts
> "CMK CMK275R SAX039R SAX" (i.e. fly outbound on the CMK 275 until you
> intercept the SAX 039, then fly that inbound to SAX). In the good old
> days of 2 VOR receivers, this is trivial to fly; the radios don't know
> or care that the cross-radial fix you're going to doesn't have a name.
> But, how would you fly that with a GPS?
>
> I've been puzzling over that one for a week or so now, and the best I
> can come up with is to use the GPS's OBS mode to track outbound on the
> CMK 275, and set up a VOR receiver to indicate the crossing radial.
>
> Can anybody figure out a way to set it up purely on the GPS? I'm using
> a CNX-80, but it might be interesting to see how other units would do it
> too.
>

Determine the point of intersection of the radials and fly direct to that
point from CMK then direct to SAX.

[[email protected]]

On Tue, 30 Nov 2004 22:39:38 -0500, Roy Smith > wrote:

>Apparently, if you file IFR HPN -> MMU, you get a clearance which starts
>"CMK CMK275R SAX039R SAX" (i.e. fly outbound on the CMK 275 until you
>intercept the SAX 039, then fly that inbound to SAX). In the good old
>days of 2 VOR receivers, this is trivial to fly; the radios don't know
>or care that the cross-radial fix you're going to doesn't have a name.
>But, how would you fly that with a GPS?
>
>I've been puzzling over that one for a week or so now, and the best I
>can come up with is to use the GPS's OBS mode to track outbound on the
>CMK 275, and set up a VOR receiver to indicate the crossing radial.
>
>Can anybody figure out a way to set it up purely on the GPS? I'm using
>a CNX-80, but it might be interesting to see how other units would do it
>too.

If you get it a lot, set up a user waypoint.

If you know the distance off one of the VOR's, it should be easy.

If you fly it repeatedly, push the MARK button (or equivalent) the
next time you fly over it.

[Ron Rosenfeld]

On Tue, 30 Nov 2004 22:39:38 -0500, Roy Smith > wrote:

>Apparently, if you file IFR HPN -> MMU, you get a clearance which starts
>"CMK CMK275R SAX039R SAX" (i.e. fly outbound on the CMK 275 until you
>intercept the SAX 039, then fly that inbound to SAX). In the good old
>days of 2 VOR receivers, this is trivial to fly; the radios don't know
>or care that the cross-radial fix you're going to doesn't have a name.
>But, how would you fly that with a GPS?
>
>I've been puzzling over that one for a week or so now, and the best I
>can come up with is to use the GPS's OBS mode to track outbound on the
>CMK 275, and set up a VOR receiver to indicate the crossing radial.
>
>Can anybody figure out a way to set it up purely on the GPS? I'm using
>a CNX-80, but it might be interesting to see how other units would do it
>too.

The only way I know of to due it "purely" with the GPS mode would be to set
up a user waypoint at the intersection of those two radials.

But what I would do with my CNX80, assuming that was not worthwhile, would
be to also use it's VOR mode. I would set up an OBS track to SAX on the
039R. That should give a display on the screen. I would then use the VOR
mode to fly direct CMK and outbound on the CMK 275 until I intercepted the
course to SAX. Then I would switch back to GPS mode.


--ron

[gwengler]

Roy Smith > wrote in message >...
> Apparently, if you file IFR HPN -> MMU, you get a clearance which starts
> "CMK CMK275R SAX039R SAX" (i.e. fly outbound on the CMK 275 until you
> intercept the SAX 039, then fly that inbound to SAX). In the good old
> days of 2 VOR receivers, this is trivial to fly; the radios don't know
> or care that the cross-radial fix you're going to doesn't have a name.
> But, how would you fly that with a GPS?
>
> I've been puzzling over that one for a week or so now, and the best I
> can come up with is to use the GPS's OBS mode to track outbound on the
> CMK 275, and set up a VOR receiver to indicate the crossing radial.
>
> Can anybody figure out a way to set it up purely on the GPS? I'm using
> a CNX-80, but it might be interesting to see how other units would do it
> too.

Use the GPS's OBS mode to fly outbound on the radial from the first
VOR. Then call up the second VOR on the GPS (for example through the
Nearest function or the VOR page or on any other information page).
There you will see the actual radial/bearing from or to the second VOR
depending on how you have set it up. Once you reach the required
radial from the second VOR you go direct to or continue using the OBS
mode with the second VOR as a new waypoint.

Gerd, ATP
T182 C-FDOW

[Mike Rapoport]

On a 430/530 you can create a user waypoint based on radials from waypoints
in the database. I created someof these user waypoints when I was given the
same clearance often. Most of the time I use the method you described with
OBS and a VOR reciever to locate the crossing radial.

Mike
MU-2


"Roy Smith" > wrote in message
...
> Apparently, if you file IFR HPN -> MMU, you get a clearance which starts
> "CMK CMK275R SAX039R SAX" (i.e. fly outbound on the CMK 275 until you
> intercept the SAX 039, then fly that inbound to SAX). In the good old
> days of 2 VOR receivers, this is trivial to fly; the radios don't know
> or care that the cross-radial fix you're going to doesn't have a name.
> But, how would you fly that with a GPS?
>
> I've been puzzling over that one for a week or so now, and the best I
> can come up with is to use the GPS's OBS mode to track outbound on the
> CMK 275, and set up a VOR receiver to indicate the crossing radial.
>
> Can anybody figure out a way to set it up purely on the GPS? I'm using
> a CNX-80, but it might be interesting to see how other units would do it
> too.

[Roy Smith]

gwengler > wrote:
>Use the GPS's OBS mode to fly outbound on the radial from the first
>VOR. Then call up the second VOR on the GPS (for example through the
>Nearest function or the VOR page or on any other information page).
>There you will see the actual radial/bearing from or to the second VOR
>depending on how you have set it up. Once you reach the required
>radial from the second VOR you go direct to or continue using the OBS
>mode with the second VOR as a new waypoint.

Sounds like a good plan, thanks!

[Stan Prevost]

Roy, just curious, does the CNX-80 use the facility magnetic variation when
setting up a VOR radial in OBS mode? I believe the Apollo GX-60 does not.
I think the 430/530 does use the facility variation, and I wonder if Garmin
changed what the Apollo units do, either in the CNX-80 or going to the
GNS-480.

There is a four degree difference between facility variation and actual
variation at our local VOR. It would make two miles of crosstrack error at
30 miles from the VOR, usually not a big deal, but worth knowing about.

Stan


"Roy Smith" > wrote in message
...
> Apparently, if you file IFR HPN -> MMU, you get a clearance which starts
> "CMK CMK275R SAX039R SAX" (i.e. fly outbound on the CMK 275 until you
> intercept the SAX 039, then fly that inbound to SAX). In the good old
> days of 2 VOR receivers, this is trivial to fly; the radios don't know
> or care that the cross-radial fix you're going to doesn't have a name.
> But, how would you fly that with a GPS?
>
> I've been puzzling over that one for a week or so now, and the best I
> can come up with is to use the GPS's OBS mode to track outbound on the
> CMK 275, and set up a VOR receiver to indicate the crossing radial.
>
> Can anybody figure out a way to set it up purely on the GPS? I'm using
> a CNX-80, but it might be interesting to see how other units would do it
> too.

[John R. Copeland]

From page 37 of the GNS 480 Pilot's Guide;
"NOTE: When using the OBS mode with a VOR station, the GNS 480
will use the station declination of the VOR.
For other waypoints, the GNS 480 will use magnetic variation based on
your present position."

In my opinion, it should use VOR station declination *only* in OBS
mode, but in Salem they chose to use it in all modes involving VORs.
That wasn't their original choice, but the UPS pilots wanted it that =
way.
---JRC---

"Stan Prevost" > wrote in message =
...
> Roy, just curious, does the CNX-80 use the facility magnetic variation =
when=20
> setting up a VOR radial in OBS mode? I believe the Apollo GX-60 does =
not.=20
> I think the 430/530 does use the facility variation, and I wonder if =
Garmin=20
> changed what the Apollo units do, either in the CNX-80 or going to the =

> GNS-480.
>=20
> There is a four degree difference between facility variation and =
actual=20
> variation at our local VOR. It would make two miles of crosstrack =
error at=20
> 30 miles from the VOR, usually not a big deal, but worth knowing =
about.
>=20
> Stan
>=20
> "Roy Smith" > wrote in message=20
> ...
>> Apparently, if you file IFR HPN -> MMU, you get a clearance which =
starts
>> "CMK CMK275R SAX039R SAX" (i.e. fly outbound on the CMK 275 until you
>> intercept the SAX 039, then fly that inbound to SAX). In the good =
old
>> days of 2 VOR receivers, this is trivial to fly; the radios don't =
know
>> or care that the cross-radial fix you're going to doesn't have a =
name.
>> But, how would you fly that with a GPS?
>>
>> I've been puzzling over that one for a week or so now, and the best I
>> can come up with is to use the GPS's OBS mode to track outbound on =
the
>> CMK 275, and set up a VOR receiver to indicate the crossing radial.
>>
>> Can anybody figure out a way to set it up purely on the GPS? I'm =
using
>> a CNX-80, but it might be interesting to see how other units would do =
it
>> too.=20
>

[Stan Prevost]

Thanks, John.


"John R. Copeland" > wrote in message
...
From page 37 of the GNS 480 Pilot's Guide;
"NOTE: When using the OBS mode with a VOR station, the GNS 480
will use the station declination of the VOR.
For other waypoints, the GNS 480 will use magnetic variation based on
your present position."

In my opinion, it should use VOR station declination *only* in OBS
mode, but in Salem they chose to use it in all modes involving VORs.
That wasn't their original choice, but the UPS pilots wanted it that way.
---JRC---

"Stan Prevost" > wrote in message
...
> Roy, just curious, does the CNX-80 use the facility magnetic variation
> when
> setting up a VOR radial in OBS mode? I believe the Apollo GX-60 does not.
> I think the 430/530 does use the facility variation, and I wonder if
> Garmin
> changed what the Apollo units do, either in the CNX-80 or going to the
> GNS-480.
>
> There is a four degree difference between facility variation and actual
> variation at our local VOR. It would make two miles of crosstrack error
> at
> 30 miles from the VOR, usually not a big deal, but worth knowing about.
>
> Stan
>
> "Roy Smith" > wrote in message
> ...
>> Apparently, if you file IFR HPN -> MMU, you get a clearance which starts
>> "CMK CMK275R SAX039R SAX" (i.e. fly outbound on the CMK 275 until you
>> intercept the SAX 039, then fly that inbound to SAX). In the good old
>> days of 2 VOR receivers, this is trivial to fly; the radios don't know
>> or care that the cross-radial fix you're going to doesn't have a name.
>> But, how would you fly that with a GPS?
>>
>> I've been puzzling over that one for a week or so now, and the best I
>> can come up with is to use the GPS's OBS mode to track outbound on the
>> CMK 275, and set up a VOR receiver to indicate the crossing radial.
>>
>> Can anybody figure out a way to set it up purely on the GPS? I'm using
>> a CNX-80, but it might be interesting to see how other units would do it
>> too.
>

[Roy Smith]

"Stan Prevost" > wrote:
> Roy, just curious, does the CNX-80 use the facility magnetic variation when
> setting up a VOR radial in OBS mode?

According to the CNX-80 manual, facility variation is used in OBS mode
when the waypoint is a VOR, but not in Course-To or Course-From mode
(and not in OBS mode when the waypoint is not a VOR).

All things considered, I think that makes a lot of sense.

> I believe the Apollo GX-60 does not.

I just looked at the GX-60 manual, in the section on OBS mode. It
doesn't say one way or the other, which I assume means it does not take
variation into account.

[John R. Copeland]

"Roy Smith" > wrote in message =
...
> "Stan Prevost" > wrote:
>> Roy, just curious, does the CNX-80 use the facility magnetic =
variation when=20
>> setting up a VOR radial in OBS mode?
>=20
> According to the CNX-80 manual, facility variation is used in OBS mode =

> when the waypoint is a VOR, but not in Course-To or Course-From mode=20
> (and not in OBS mode when the waypoint is not a VOR).
>=20
> All things considered, I think that makes a lot of sense.
>=20
>> I believe the Apollo GX-60 does not.
>=20
> I just looked at the GX-60 manual, in the section on OBS mode. It=20
> doesn't say one way or the other, which I assume means it does not =
take=20
> variation into account.

Roy:
I've never yet used the CNX 80 "Course To" or "Course From" in flight,
but the GNS 480 Windows Simulator appears to me that it uses
VOR station declination for those modes, as well as all other modes
whenever VORs are involved as waypoints.
---JRC---

[Stan Prevost]

"Roy Smith" > wrote in message
...
>
> I just looked at the GX-60 manual, in the section on OBS mode. It
> doesn't say one way or the other, which I assume means it does not take
> variation into account.

The manual shows what data is included in the database for a VOR, and it
does not include facility variation.

[Greg Esres]

<<CMK CMK275R SAX039R SAX>>

Hmmmm...does it appear this way on a flight progress strip? Duats
won't accept that sort of thing.

[Newps]

Greg Esres wrote:
> <<CMK CMK275R SAX039R SAX>>
>
> Hmmmm...does it appear this way on a flight progress strip? Duats
> won't accept that sort of thing.

A flight progress strip would have a radial and DME.

[Steven P. McNicoll]

"Greg Esres" > wrote in message
...
> <<CMK CMK275R SAX039R SAX>>
>
> Hmmmm...does it appear this way on a flight progress strip? Duats
> won't accept that sort of thing.
>

For ATC Flight Data processing the input would be CMK.CMK275..SAX039.SAX, it
appears on the strip without the dots.

[[email protected]]

On Thu, 02 Dec 2004 04:11:34 GMT, Greg Esres >
wrote:

><<CMK CMK275R SAX039R SAX>>
>
>Hmmmm...does it appear this way on a flight progress strip? Duats
>won't accept that sort of thing.


It will if you use distance, e.g., CMK275023, the last three digits
being the distance from Carmel on the 275 until you intercept the
039.

You just need to measure the distance, or play with the planner and
maybe do a binary search along the 275R until you get the 039R to
SAX.

[Roy Smith]

In article >,
"Stan Prevost" > wrote:

> "Roy Smith" > wrote in message
> ...
> >
> > I just looked at the GX-60 manual, in the section on OBS mode. It
> > doesn't say one way or the other, which I assume means it does not take
> > variation into account.
>
> The manual shows what data is included in the database for a VOR, and it
> does not include facility variation.

That would be another good clue that it doesn't use it :-)

[[email protected]]

On Thu, 02 Dec 2004 12:43:01 GMT, wrote:

>On Thu, 02 Dec 2004 04:11:34 GMT, Greg Esres >
>wrote:
>
>><<CMK CMK275R SAX039R SAX>>
>>
>>Hmmmm...does it appear this way on a flight progress strip? Duats
>>won't accept that sort of thing.
>
>
>It will if you use distance, e.g., CMK275023, the last three digits
>being the distance from Carmel on the 275 until you intercept the
>039.
>
>You just need to measure the distance, or play with the planner and
>maybe do a binary search along the 275R until you get the 039R to
>SAX.


By the way, once you have the correct distance, DUATS will show the
lat/lon of the junction, which will give Roy a way to enter the
junction into the GPS as a waypoint.

[[email protected]]

On Thu, 02 Dec 2004 19:41:32 GMT, wrote:

>On Thu, 02 Dec 2004 12:43:01 GMT, wrote:
>
>>On Thu, 02 Dec 2004 04:11:34 GMT, Greg Esres >
>>wrote:
>>
>>><<CMK CMK275R SAX039R SAX>>
>>>
>>>Hmmmm...does it appear this way on a flight progress strip? Duats
>>>won't accept that sort of thing.
>>
>>
>>It will if you use distance, e.g., CMK275023, the last three digits
>>being the distance from Carmel on the 275 until you intercept the
>>039.
>>
>>You just need to measure the distance, or play with the planner and
>>maybe do a binary search along the 275R until you get the 039R to
>>SAX.
>
>
>By the way, once you have the correct distance, DUATS will show the
>lat/lon of the junction, which will give Roy a way to enter the
>junction into the GPS as a waypoint.


Which, as I think about it, would be superfluous, since having the
radial and distance should be enough to enter a GPS waypoint.

Sorry

[Andrew Gideon]

Roy Smith wrote:

> Sounds like a good plan, thanks!

Yes, thanks! I was going over the 430 manual last night trying to find
something of this sort, but I missed it.

Those flying behind the navcoms in newer Cessnas have a similar/easier
option. The nav side can be set to display the to/from radial instead of
the standby frequency. I liked the awareness that provided, given that I
could see "how close I was" to some chosen radial even before the needle
had "come alive".

- Andrew

[Roy Smith]

Andrew Gideon > wrote:
>Roy Smith wrote:
>
>> Sounds like a good plan, thanks!
>
>Yes, thanks! I was going over the 430 manual last night trying to find
>something of this sort, but I missed it.
>
>Those flying behind the navcoms in newer Cessnas have a similar/easier
>option. The nav side can be set to display the to/from radial instead of
>the standby frequency. I liked the awareness that provided, given that I
>could see "how close I was" to some chosen radial even before the needle
>had "come alive".

You can do that on the CNX-80 too. In NAV mode, hit the MON soft-key
to put it in monitor mode. It then shows you the from radial of the
VOR in the standby slot.

[Greg Esres]

<<It will if you use distance, e.g., CMK275023, the last three digits
being the distance from Carmel on the 275 until you intercept the
039.>>

I know, but the radial to radial is more elegant.

[Greg Esres]

<<input would be CMK.CMK275..SAX039.SAX>>

Cool. Do you disagree with Newps in that the DME would NOT appear on
the flight progress strip (unless it was input) ?

[Steven P. McNicoll]

"Greg Esres" > wrote in message
...
> <<input would be CMK.CMK275..SAX039.SAX>>
>
> Cool. Do you disagree with Newps in that the DME would NOT appear on
> the flight progress strip (unless it was input) ?
>

DME would appear on the strip only if it was entered.

[Greg Esres]

<<DME would appear on the strip only if it was entered>>

Thank you.