using GPS distance on a Garmin 430 for a DME approach

NoHeat

NoHeat

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Suppose you want to hand-fly a VOR or localizer approach that requires DME distance. I know how to do it in a plane with an older panel with DME and a NAV radio. But suppose instead you're in a plane with one or two Garmin 430's, and no DME. How would you set up the 430s for this hand-flown approach, with a distance to the nav-aid constantly displayed in lieu of the DME? I'm wondering if there must be a way to keep the distance to the same nav-aid shown constantly, even as you pass various waypoints in the approach.
 
The easiest way is to just load the approach in the 430, and the significant fix points will be displayed on the map and in the FPL. Alternatively, you could put the GPS direct to the navaid, and select the Nav 1 page on the 430 and read the distance there.
 
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Ron Levy said:
The easiest way is to just load the approach in the 430, and the significant fix points will be displayed on the map and in the FPL. Alternatively, you could put the GPS direct to the navaid, and select the Nav 1 page on the 430 and read the distance there.
Click to expand...

Garmin 430s etc are loaded with percision approach data and it all works out. The Garmin provides the DME data with the freq loaded and VLOC for localizer guidance.

You can't do that with a KLN 89 or 94 series IFR GPS.
Look at the ILS/DME Rwy 25L at LAS. You can fly the approach using the KLN gps recievers. NAV 1 tuned to the LOC freq and the GPS loaded to the VORTAC. The DME is from the VORTAC which is in the data base.

Look at LAS Rwy 1L ILS/DME, can't fly that one with the KLN. The DME is tied to the LOC and not the VORTAC. The LOC /DME antenna location is not in the GPS data base. No can fly. Same with the VGT Rwy 12L ILS, and I just found the ILS into Bellingham has the same limitation.

Make sure you know your GPS capability and limitations and how the approaches are designed.
 
BillTIZ said:
Garmin 430s etc are loaded with percision approach data and it all works out. The Garmin provides the DME data with the freq loaded and VLOC for localizer guidance.

You can't do that with a KLN 89 or 94 series IFR GPS.
Look at the ILS/DME Rwy 25L at LAS. You can fly the approach using the KLN gps recievers. NAV 1 tuned to the LOC freq and the GPS loaded to the VORTAC. The DME is from the VORTAC which is in the data base.

Look at LAS Rwy 1L ILS/DME, can't fly that one with the KLN. The DME is tied to the LOC and not the VORTAC. The LOC /DME antenna location is not in the GPS data base. No can fly. Same with the VGT Rwy 12L ILS, and I just found the ILS into Bellingham has the same limitation.

Make sure you know your GPS capability and limitations and how the approaches are designed.
Click to expand...

I dealt with this on a KLN-94 by creating a flight plan that used the DME-defined stepdowns as waypoints. This made it easy, but of course you have to know which approach you're going to be flying far enough in advance to be able to set it up in a low-workload phase of flight. This is an issue for me because the nearest ILS to Palo Alto gets its DME from the Moffett TACAN (NUQ). It doesn't have a co-located VOR and is not in the database. (I believe the 430 does have it.)
 
Palmpilot said:
I dealt with this on a KLN-94 by creating a flight plan that used the DME-defined stepdowns as waypoints. This made it easy, but of course you have to know which approach you're going to be flying far enough in advance to be able to set it up in a low-workload phase of flight. This is an issue for me because the nearest ILS to Palo Alto gets its DME from the Moffett TACAN (NUQ). It doesn't have a co-located VOR and is not in the database. (I believe the 430 does have it.)
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AC 90-108 Use of Suitable Area Navigation (RNAV) Systems on Conventional
Routes and Procedures states in section 9. OPERATING REQUIREMENTS AND CONSIDERATIONS:

<snip>

b. RNAV System Database Considerations.

<snip>

(2) Pilots must extract waypoints, NAVAIDs, and fixes by name from the onboard navigation database and comply with the charted procedure or route.

<snip>

c. Operating Requirements:

For the purposes described in this AC, pilots may not manually enter published procedure or route waypoints via latitude/longitude, place/bearing, or place/bearing/distance into the aircraft system.
 
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TMetzinger said:
And is it the 530 that gives you GPS distance to any navaid you tune, once it's identified?
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If the Navaid is a VOR or VORTAC, the 530 can be configured to display this in the window directly above the status area. It will display the ident code, the frequency, and the GPS distance. If you tune a Localizer, it will display the frequency, the ident code I-xxx, and that it is a localizer, but it doesn't display the distance or a radial.
 
John Collins said:
AC 90-108 Use of Suitable Area Navigation (RNAV) Systems on Conventional
Routes and Procedures states in section 9. OPERATING REQUIREMENTS AND CONSIDERATIONS:

<snip>

b. RNAV System Database Considerations.

<snip>

(2) Pilots must extract waypoints, NAVAIDs, and fixes by name from the onboard navigation database and comply with the charted procedure or route.

<snip>

c. Operating Requirements:

For the purposes described in this AC, pilots may not manually enter published procedure or route waypoints via latitude/longitude, place/bearing, or place/bearing/distance into the aircraft system.
Click to expand...

So does that mean that entering the stepdown waypoints by name, as I did, was the only correct way to do it, or is it also OK to enter the DME station by name (if it's in the database), and just read the distance to the DME station directly off the GPS, since the DME distances are shown on the chart?

http://download.aopa.org/ustprocs/current/SW-2/nuq_ils_or_loc_dme_rwy_32r.pdf
 
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Palmpilot said:
So does that mean that entering the stepdown waypoints by name, as I did, was the only correct way to do it, or is it also OK to enter the DME station by name (if it's in the database), and just read the distance to the DME station directly off the GPS, since the DME distances are shown on the chart?

http://download.aopa.org/ustprocs/current/SW-2/nuq_ils_or_loc_dme_rwy_32r.pdf
Click to expand...

Either method is acceptable. What isn't acceptable is using the waypoints in lieu of flying the procedure or making up user waypoints from Lat-Long or other raw data such as VOR radial-distance. You still need to use the lateral guidance from the ground based facility for the lateral navigation from the FAF to the MAP and in the case of a localizer, you must always display the localizer anytime you are tracking the localizer.
 
John Collins said:
Either method is acceptable. What isn't acceptable is using the waypoints in lieu of flying the procedure or making up user waypoints from Lat-Long or other raw data such as VOR radial-distance. You still need to use the lateral guidance from the ground based facility for the lateral navigation from the FAF to the MAP and in the case of a localizer, you must always display the localizer anytime you are tracking the localizer.
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Understood. It may not have been clear from my post that I was using a conventional nav/com to follow the glideslope and localizer. The reason for making all those stepdown waypoints into a GPS flight plan was that I wouldn't want to be spelling them out letter-by-letter while trying to track the ILS!

I wish more of the rental planes I fly had the 430, because it sounds so much easier to use.
 
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I just read this thread properly.

I think John is saying that either using the waypoints from the GPS database or entering Direct->NAVAID and then reading off distance is acceptable (when the NAVAID is also in the database).

But if you read the GPS distance to the DME station by entering Direct->NAVAID on a GPS (rather than using the stepdown waypoints), don't you get a different result than using actual DME, due to altitude?

--EDIT: Although thinking about it, the differences are rather small at the typical low final approach segment altitudes / distances.
 
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tiger said:
I just read this thread properly.

I think John is saying that either using the waypoints from the GPS database or entering Direct->NAVAID and then reading off distance is acceptable (when the NAVAID is also in the database).

But if you read the GPS distance to the DME station by entering Direct->NAVAID on a GPS (rather than using the stepdown waypoints), don't you get a different result than using actual DME, due to altitude?

--EDIT: Although thinking about it, the differences are rather small at the typical low final approach segment altitudes / distances.
Click to expand...
Your additional thought is correct -- in that situation, the difference is not significant.
 
Palmpilot said:
I dealt with this on a KLN-94 by creating a flight plan that used the DME-defined stepdowns as waypoints. This made it easy, but of course you have to know which approach you're going to be flying far enough in advance to be able to set it up in a low-workload phase of flight. This is an issue for me because the nearest ILS to Palo Alto gets its DME from the Moffett TACAN (NUQ). It doesn't have a co-located VOR and is not in the database. (I believe the 430 does have it.)
Click to expand...

Which ILS approach are you referring to? The ILS into Moffut uses NUQ 117.6 Ch 123 for distance. So you could load NUQ into the KLN94 for distance and tune the ILS 110.35 to VOR 1 if that is your ILS reciever.
 
BillTIZ said:
Which ILS approach are you referring to? The ILS into Moffut uses NUQ 117.6 Ch 123 for distance. So you could load NUQ into the KLN94 for distance and tune the ILS 110.35 to VOR 1 if that is your ILS reciever.
Click to expand...

Yes that's the approach. From the post you replied to:

"This is an issue for me because the nearest ILS to Palo Alto gets its DME from the Moffett TACAN (NUQ). It doesn't have a co-located VOR and is not in the database."

If you can find the NUQ TACAN in the KLN-94 database, I'd love to know how, because every time I've tried, it's not there.
 
Palmpilot said:
Yes that's the approach. From the post you replied to:

"This is an issue for me because the nearest ILS to Palo Alto gets its DME from the Moffett TACAN (NUQ). It doesn't have a co-located VOR and is not in the database."

If you can find the NUQ TACAN in the KLN-94 database, I'd love to know how, because every time I've tried, it's not there.
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Ok, thanks, I was just looking at the approach plate. Interesting that NUQ would not be in the data base as a navigational reference, not as an approach aide. I'll have to look next time I'm at the airplane.

The KLN-89B / -94 are "non-precision" approach GPS units and not set up for "precision" or ILS approaches. Still funny that the navaid is not loaded.

If you had a DME reciever, you could tune 117.6 and get DME information for the approach and the GPS is essentially worthless at that point. You could set it up for KNUQ for an airport reference? In that is loaded in the database.

Another interesting failure of the KLN line. We updated the KLN-89B for "North America" to have the current chart cycle for a recent trip to Alaska through Canada. Well, we found out that all of the airports, NDBs, VORs, etc were loaded in the database. But no GPS approaches or airport data, runway or freqs where loaded.

Glad we didn't need the GPS approach into Watson Lake or Fort Nelson. :yikes:
 
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BillTIZ said:
Ok, thanks, I was just looking at the approach plate. Interesting that NUQ would not be in the data base as a navigational reference, not as an approach aide. I'll have to look next time I'm at the airplane.

The KLN-89B / -94 are "non-precision" approach GPS units and not set up for "precision" or ILS approaches. Still funny that the navaid is not loaded.
Click to expand...

I was thinking that it might have something to do with memory size limitations on the KLN-94, except that wouldn't make sense, because they have all the ILS stepdown fixes in the database. I tried it again recently using a plane that's equipped with a GX-60, and had the same problem. I'm pretty sure I have found the NUQ TACAN in the GNS-430 database.

If you had a DME reciever, you could tune 117.6 and get DME information for the approach and the GPS is essentially worthless at that point.
Click to expand...

The club I usually fly out of has two C-172SPs that are factory-equipped with the KLN-94 and no DME. If they had DMEs in them, then yes, I certainly would have used that, as I have done in the past with appropriately equipped aircraft.

You could set it up for KNUQ for an airport reference? In that is loaded in the database.
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I'm pretty sure the airport is in the database, but I think the TACAN is at least a mile from the airport reference point, so that wouldn't work. It probably wouldn't comply with FAA published guidance on GPS substitution for DME either.
 
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