Garmin GNS430W Experts Instrument Approach DME Arc to LOC

[fly4usa]

I am a CFI INST and have an Instrument student. Been CFI-I-ME for 33 years but have not instructed much last 20 years. In that time GNS430W came out 18 yrs ago. So I am learning as well. Airliners don't have Garmin. I am pretty proficient with the 430W, with RNAV approaches. However something happened with waypoint cycling on a DME arc to LOC approach.

I wanted my student to do a LOC approach, as well as a DME arc, timed approach, and more complicated missed. The KMKL LOC 02 was pretty much made to order. All we had done were very basic or typical RNAV LPV approaches with HOLD entry. A

The plane has a GNS430W and two G5's. Only non GPS approaches it can do are VOR, having no GS receiver. It may also be limited by having no DME. That is OK as the LPV counts as a precision approach for check. [Agree LVP is substitute for ILS on check ride?]

My issue is the GPS did not cycle as expected from Arc to final approach segment. Keep in mind the plane has all the IFR requirements and current Garmin IFR database.

So off we went VFR to to KMKL for the ILS or LOC 2 in VFR, student under hood. Contacted KMKL tower about 5 miles from IAF SKOAL, start of 12 DME arc. Keep in mind the approach says:

"DME required. RADAR required for procedure entry."

So that is clear. GPS is not an acceptable substitute for DME on this Approach. Since we were in VFR no issue. Also the RADAR required for procedure entry? [Comments and Thoughts]

Before you all bash me all the planes I have flown recently have 2 DME, 2 GPS, LOC/GS/MB and 3 IRU's, all integrated into one FMS. The other GA plane I fly has GTN750 with all the bells, whistles and options.

Approach is loaded and activated. Proceeded direct to SKOAL. The GNS430W gave turn guidance to start the ARC which was magenta. All is good.

- The issue started as we proceeded near the final approach course just inside OZZIE.​

​

- LOC frequency in active, and ready to select VLOC.​

​

- As we passed the end of arc waypoint (not depicted on chart oe FPL) it stayed white and OZZIE did not cycle, also WHITE. There was a gap from end of arc to approach segment from OZZIE to MERSY, still white.​

​

- I deleted the ARC or brought (FAF) MERSY up as next way point (I forgot) mow. The the map showed magenta line.​

​

- VLOC was already selected. G5 was giving guidance, course set, CDI (green). I thought it had to be done manually. May be selecting MERSY selected VLOC automatically?​

​

- We timed approach and did missed. However we did not do published miss but flew West to leave area and return to departure airport.​

​

- The subsequent RNAV LVP at home airport went as expected.​

So what happened? First is DME really needed to do this in IMC or is an IFR GPS a substitute?

What was the issue with way point cycling (if any)? Other approaches with a HOLD entry you have to clear the HOLD. You have to clear ARC or bring FAF up?

I called Garmin and the tech said he would test it, see if there is a glitch. Will send me an email. Possible but pretty sure it's me.




.

 

[midlifeflyer]

Hard to tell exactly what happened without trying to reproduce it. Assuming the approach was loaded and the arc activated, the GPS should have sequenced to the inbound. (I just ran it in the trainer and it worked as expected)

OTOH, if you are not talking about the GPS sequencing, but a failure to auto-switch the CDI, if MKL VOR was active and being used for the arc with I-MKL in standby, it would not have auto-switched. Autoswitch is GPS to VLOC, not VLOC to VLOC. So if you were on green needles throughout, I would expect the GPS to sequence but for VLOC to say with the VOR,

(IFR GPS orientation is absolutely substitute for the DME arc. But consider when you might actually fly one for real - during a GPS failure - and you don't have DME.)

 

[MauleSkinner]

But consider when you might actually fly one for real - during a GPS failure - and you don't have DME.)

While I realize that most pilots prefer vectors to final, a DME arc (or PT, or other transition) will often result in less time to the airport. Or, there might be a radar outage requiring a full procedure.

 

[midlifeflyer]

While I realize that most pilots prefer vectors to final, a DME arc (or PT, or other transition) will often result in less time to the airport. Or, there might be a radar outage requiring a full procedure.

I wasn't comparing to vectors to final. I was comparing to using an RNAV approach to the same runway. It's going to be the rare approach where a DME arc is going to beat out a TAA. I know they exist, there's one near me, but unless it's like this one, to an ILS, there's going to be a minimums penalty.

Looking at this one, The total distance from the IAF to the runway using the arc is about 22 nm. And it's a short arc so the arc distance is almost a straight line. OTOH, from the RNAV IAF, the total distance is under 17nm. The two IAFs are about 6nm apart. There may be a direction in the northeast quadrant where the extra 5 NM becomes a benefit, but other than that, the RNAV wins.

But looking at this one, the first thing I noticed other than that DME is required (a MON situation, you can't use it without real DME), is that the procedure is unusable in your radar outage situation.

 

[luvflyin]

I am a CFI INST and have an Instrument student. Been CFI-I-ME for 33 years but have not instructed much last 20 years. In that time GNS430W came out 18 yrs ago. So I am learning as well. Airliners don't have Garmin. I am pretty proficient with the 430W, with RNAV approaches. However something happened with waypoint cycling on a DME arc to LOC approach.

I wanted my student to do a LOC approach, as well as a DME arc, timed approach, and more complicated missed. The KMKL LOC 02 was pretty much made to order. All we had done were very basic or typical RNAV LPV approaches with HOLD entry. A

The plane has a GNS430W and two G5's. Only non GPS approaches it can do are VOR, having no GS receiver. It may also be limited by having no DME. That is OK as the LPV counts as a precision approach for check. [Agree LVP is substitute for ILS on check ride?]

My issue is the GPS did not cycle as expected from Arc to final approach segment. Keep in mind the plane has all the IFR requirements and current Garmin IFR database.

So off we went VFR to to KMKL for the ILS or LOC 2 in VFR, student under hood. Contacted KMKL tower about 5 miles from IAF SKOAL, start of 12 DME arc. Keep in mind the approach says:

"DME required. RADAR required for procedure entry."

So that is clear. GPS is not an acceptable substitute for DME on this Approach. Since we were in VFR no issue. Also the RADAR required for procedure entry? [Comments and Thoughts]

Before you all bash me all the planes I have flown recently have 2 DME, 2 GPS, LOC/GS/MB and 3 IRU's, all integrated into one FMS. The other GA plane I fly has GTN750 with all the bells, whistles and options.

Approach is loaded and activated. Proceeded direct to SKOAL. The GNS430W gave turn guidance to start the ARC which was magenta. All is good.

- The issue started as we proceeded near the final approach course just inside OZZIE.​

​

- LOC frequency in active, and ready to select VLOC.​

​

- As we passed the end of arc waypoint (not depicted on chart oe FPL) it stayed white and OZZIE did not cycle, also WHITE. There was a gap from end of arc to approach segment from OZZIE to MERSY, still white.​

​

- I deleted the ARC or brought (FAF) MERSY up as next way point (I forgot) mow. The the map showed magenta line.​

​

- VLOC was already selected. G5 was giving guidance, course set, CDI (green). I thought it had to be done manually. May be selecting MERSY selected VLOC automatically?​

​

- We timed approach and did missed. However we did not do published miss but flew West to leave area and return to departure airport.​

​

- The subsequent RNAV LVP at home airport went as expected.​

So what happened? First is DME really needed to do this in IMC or is an IFR GPS a substitute?

What was the issue with way point cycling (if any)? Other approaches with a HOLD entry you have to clear the HOLD. You have to clear ARC or bring FAF up?

I called Garmin and the tech said he would test it, see if there is a glitch. Will send me an email. Possible but pretty sure it's me.



View attachment 121312
.

GPS is an authorized substitute for DME. I don’t remember ever reading that using it to fly Arc’s is excluded. RADAR required for procedure entry is because there is no connection to the Enroute Structure. There was probably an Airway between GQE and MKL that got decommissioned. Probably around 24MAR22. Why the 430 wouldn’t sequence at OZZIE, I dunno. Did you fly the Arc even though you thought it wasn’t authorized? Did the 430 give proper turn anticipation to ‘fly by’ OZZIE and and roll you out on the Localizer?

 

[John Collins]

First question regarding substitution of DME when flying the arc, yes it is explicitly approved, see AIM 1-2-3.

​

c. Uses of Suitable RNAV Systems. Subject to the operating requirements, operators may use a suitable RNAV system in the following ways.
1. Determine aircraft position relative to, or distance from a VOR (see NOTE 6 below), TACAN, NDB, compass locator, DME fix; or a named fix defined by a VOR radial, TACAN course, NDB bearing, or compass locator bearing intersecting a VOR or localizer course.
2. Navigate to or from a VOR, TACAN, NDB, or compass locator.
3. Hold over a VOR, TACAN, NDB, compass locator, or DME fix.
4. Fly an arc based upon DME.

​

​

​

Because the procedure is a conventional procedure and is not connected via any airway in the enroute system, radar is required to join the procedure. With GPS, you can navigate via RNAV directly to SKOAL, in which case radar would not be needed.

If the GNS430W had the procedure loaded and you had selected SKOAL as the point to join the IAP, you should have received guidance along the DME arc and a turn before OZZIE at D214L to align with the localizer, followed by a switch from GPS guidance to VLOC as the source after completing the turn (assuming the AUX>ILS CDI Capture> is set to Auto). You would also have needed to have tuned the localizer frequency, made it the active navigation frequency, and identified it.

 

[flyingron]

You lost me. You say you have a 430W but no glideslope receiver? How does that happen?

 

[luvflyin]

First question regarding substitution of DME when flying the arc, yes it is explicitly approved, see AIM 1-2-3.

​

​

​

Because the procedure is a conventional procedure and is not connected via any airway in the enroute system, radar is required to join the procedure. With GPS, you can navigate via RNAV directly to SKOAL, in which case radar would not be needed.

If the GNS430W had the procedure loaded and you had selected SKOAL as the point to join the IAP, you should have received guidance along the DME arc and a turn before OZZIE at D214L to align with the localizer, followed by a switch from GPS guidance to VLOC as the source after completing the turn (assuming the AUX>ILS CDI Capture> is set to Auto). You would also have needed to have tuned the localizer frequency, made it the active navigation frequency, and identified it.

One caveat on RNAV direct Skoal. Yeah, the Navigator will allow you to do it. But ATC can't give you a Clearance to do it without Radar. Radar is required for them to give random RNAV routes. They can give you published routes without it. Like T123, or a Victor Airway, a Feeder or Approach Segment. So even if they put RNAV required on the Chart, Radar would still be needed for procedure entry.

 

[midlifeflyer]

You lost me. You say you have a 430W but no glideslope receiver? How does that happen?

I took

I wanted my student to do a LOC approach,

to refer to a training event, not A GS-less 430W. But I may have read it that way because I do it too.

 

[RussR]

I took

to refer to a training event, not A GS-less 430W. But I may have read it that way because I do it too.

This is from the OP:

"The plane has a GNS430W and two G5's. Only non GPS approaches it can do are VOR, having no GS receiver. "

I don't understand it either.

 

[midlifeflyer]

This is from the OP:

"The plane has a GNS430W and two G5's. Only non GPS approaches it can do are VOR, having no GS receiver. "

I don't understand it either.

I didn't catch that part. I guess I don't understand either.

 

[luvflyin]

This is from the OP:

"The plane has a GNS430W and two G5's. Only non GPS approaches it can do are VOR, having no GS receiver. "

I don't understand it either.

While we’re here on this Approach, what’s up with the Alternate Missed Approach? It and the published missed are both predicated on the same Navaid, MKL. Don’t think I’ve ever seen that before.

 

[RussR]

While we’re here on this Approach, what’s up with the Alternate Missed Approach? It and the published missed are both predicated on the same Navaid, MKL. Don’t think I’ve ever seen that before.

Yep, it defeats the whole purpose of having an alternate missed approach. I have no idea why it was done this way.

 

[MauleSkinner]

Yep, it defeats the whole purpose of having an alternate missed approach. I have no idea why it was done this way.

Maybe it’s so they can do merry-go-round approaches…one goes missed, one leaves the IAF, one leaves the alternate hold for the IAF…

 

[luvflyin]

Maybe it’s so they can do merry-go-round approaches…one goes missed, one leaves the IAF, one leaves the alternate hold for the IAF…

That would be the running Timed Approaches from a Fix scenario. I doubt very much if they do them here.

EDIT: What you described isn’t exactly what Timed Approaches would be. That requires a holding fix on the approach course. But seeing as how the Center runs the joint here, maybe they don’t like to vector to final, or maybe they don’t meet the requirements to do it. So yeah, parking a plane at PIPKI for awhile could be useful.

 

[fly4usa]

I appreciate the info. So one things was auto switch to CDI which I thought had to be manual. Thanks for that.

Some other comments are not correct likely due to not understanding.

OK GPS is substitute for DME. The limit on IAP says RADAR or DME required for arrival. Got it, GPS WAAS has RNP to do that. Right

MY QUESTION ... Doing LOC only (this plane has no GS receiver) with no DME (but GPS) can I use GPS, MERSY I-MKL 6.2DME. It says DME required at top for arrival or radar vectors. OK I can not with standing the cycling issue. Since it was not cycling I ID'ed MERSY by map and instructed to 5T it (turn, time, transition, twist talk). We did that. We got to MDA and appointed time. It worked out well on LOC. We would have got in with WX above mins. We did an alternate missed.

We did the approached timed because that was the lesson. IT IS A TIMED APPROACH. We are training. We were VFR and talking to tower only no ATC vectors. Our own NAV again training. This is real world where radar is not available. I could go into detail but even our base a non towered airport with two RNAV approaches 30 NM from MEM ARTCC can not give vectors only advise. I know I visited the ARTCC and talked to them.

There is a RWY FIX in the data base to trigger the missed. The published missed can be flown by GPS (I assume) although holding fix is a radial and DME. I assume the GPS RWY Fix could be used for missed, but timing would be required here to be totally legit. Obviously ILS (with GS which we don't have) it would be DA for missed.

We did an alternate missed and left the area back to base. We did have good lesson on DME arc, timing, 5T's, missed and nice RNAV LPV to base airport (non towered VFR own Nav. I either give student ATC instructions (as ATC would and expect readback from student) or clear them for approach, monitoring ATC and CTAF. We do file but I don't need or want to POP UP with Approach in VFR doing approaches to a rural area. If I was training in LA airspace it would be with approach.

My question was is the DME OK for LOC approach with DME fixes. Keep in mind DME required comment in IAP plate. Not withstanding the cycling issue and GARMIN note when you select it warning this is for reference only (not sure or recall exact verbiage). The answer is YES... all agree. I am sure this is pretty universal, but does anyone know exceptions.

Second is the cycling of waypoints in GARMIN. I do know about flyby and flyover. So it is possible I should have left it alone and the waypoint would have cycled if I gave it time. I have to figure that out. I get different answers about the 430 automatically switching the Stby LOC Freq into active and going from GPS to VLOC mode automatically.

As far as most pilots prefer vectors. That is not relevant. This is training. I fly for a living I am very familiar with vectors. Sure vectors are great, but my home base is 32NM from MEM ARTCC and MEM Approach. They can not give vectors. They can turn you yes, but can not clear you for approach, only help. You are required to do own NAV. How do I know? I visited ARTCC and talked to them and this topic came up. They just don't have coverage that low to monitor your approach. They will tell you to switch to CTAF and call this Freq if you miss... Radar is not assured at low altitude. I was surprised but that is a fact.

A follow up question is if an approach is not cycling, how do you recover? For example if holding at IF (hold instead of procedure turn), the ONLY way to get out of the hold and start the approach is CLEAR the hold. A direct to IF or FAF will cause problems for the 430... Please don't say select vectors. Again training and we need to do hold practice.

 

[TCABM]

…
A follow up question is if an approach is not cycling, how do you recover? For example if holding at IF (hold instead of procedure turn), the ONLY way to get out of the hold and start the approach is CLEAR the hold. A direct to IF or FAF will cause problems for the 430... Please don't say select vectors. Again training and we need to do hold practice.

Did the 430W go to SUSP when in the hold? If so, UNSUSP on the inbound leg prior to crossing the holding fix cycles to the next leg/waypoint.

I’d recommend you download Garmin’s free trainer and pre-fly the lesson so you understand the switchology.

Garmin: 400W/500W Series Trainer - WAAS Updates & Downloads

400W/500W Series Trainer - WAAS Updates & Downloads

www8.garmin.com

 

[John Collins]

The GPS may substitute for DME. That means it can be used for identifying any fix based on DME or a DME arc. You wrote: "It says DME required at top for arrival or radar vectors." That is not correct. The notes are "DME required." and "Radar required for procedure entry." The DME is used for defining the IAF SKOAL, the MKL 12 DME arc, OZZIE, MERSY WUTOT, the MAP, and the MAP hold. Radar is what is required for procedure entry, it does not mean that Radar can be used for other purposes, such as identifying fixes. Radar could be used for vectors to final if that was supported by approach control. DME arcs are primarily used in non radar environments to transition from an airway via an IAF to the final approach course. In this instance, the nearby airways were based on a VOR that has since been deleted. The old version of the procedure had an IAF at MERSY where there used to be an ADF LOM located and there were feeder routes to MERSY to join the approach from two nearby airways using VOR radials. The DME arc was added to support joining the procedure from the hold or by radar. There is a timing table to determine the MAP, but WUTOT was added as a step down to allow for a lower MDA for the localizer option, so even though you can use timing to determine the MAP, you can't use it to locate the step down at WUTOT, which requires using the DME. The DME distance can be determined either by loading the Localizer version of the procedure in the GNS430W and noting when over the named waypoint or by entering IMKL and using direct-to it to read out the distance to the localizer DME. Of course, you need to have the localizer tuned for lateral guidance along the localizer and VLOC selected to display it on your G5's. Make sure you switch to VLOC before reaching the FAF if it does not autoswitch. I would use the GNS430W built in CDI with the unit set to Nav 1 page to display GPS information such as distances and locating the MAP. At the MAP, start the miss and after climbing to 1000, I would switch back to GPS for the G5 CDI and hit OBS to get the MAP guidance.

To get the approach to sequence if it isn't doing so, go to FPL and move the cursor to the fix you wish to join in the procedure and use either "direct-to" that fix or to activate the leg, use "direct-to direct-to". If you are joining at the FAF, you have to activate the leg by using direct-to twice.

 

[midlifeflyer]

OK GPS is substitute for DME. The limit on IAP says RADAR or DME required for arrival. Got it, GPS WAAS has RNP to do that. Right

No. First, there are two separate notes. Second, WAAS is not required for GPS substitution.

We did the approached timed because that was the lesson. IT IS A TIMED APPROACH

"Timed approach" is usually used in the "timed approach from a holding fix" context, so no need to YELL about your personal use of it to refer to identifying a MAP based on a Time/Speed/Distance calculation. (And one which is unnecessary to begin with - @RussR - why is there even a timing table in an approach that requires DME? A similar issue as the alternate missed? Maybe a holdover from an earlier version? MERSY at one time a compass locator?)

I have to figure that out. I get different answers about the 430 automatically switching the Stby LOC Freq into active and going from GPS to VLOC mode automatically.

There are two things that are required for automatic switching. (1) it's set for autoswitch in the settings and (2) You have not already been navigating via VLOC. That second one is a gotcha that nabbed a friend in a checkride. FWIW, my SOP is to switch manually and treat auto switching as a backup if I make a mistake.

A follow up question is if an approach is not cycling, how do you recover? For example if holding at IF (hold instead of procedure turn), the ONLY way to get out of the hold and start the approach is CLEAR the hold. A direct to IF or FAF will cause problems for the 430... Please don't say select vectors. Again training and we need to do hold practice.

I assume you are talking about a different approach. In a hold in lieu, it automatically cycles to the next leg unless you told it not to by touching the OBS key. Clearing the hold is neither the ONLY nor the best way to continue the approach. When you are remaining in the hold, are in OBS/SUSP mode, which suspends automatic sequencing to the next leg. To end holding and sequence to the next leg, you only have to hit the OBS key.

The silly responses about vectors aside, these are pretty basic questions. It sounds like you may need a bit of one-on-one ground with your instructor on system operation.

 

[luvflyin]

I appreciate the info. So one things was auto switch to CDI which I thought had to be manual. Thanks for that.

Some other comments are not correct likely due to not understanding.

OK GPS is substitute for DME. The limit on IAP says RADAR or DME required for arrival. Got it, GPS WAAS has RNP to do that. Right

MY QUESTION ... Doing LOC only (this plane has no GS receiver) with no DME (but GPS) can I use GPS, MERSY I-MKL 6.2DME. It says DME required at top for arrival or radar vectors. OK I can not with standing the cycling issue. Since it was not cycling I ID'ed MERSY by map and instructed to 5T it (turn, time, transition, twist talk). We did that. We got to MDA and appointed time. It worked out well on LOC. We would have got in with WX above mins. We did an alternate missed.

We did the approached timed because that was the lesson. IT IS A TIMED APPROACH. We are training. We were VFR and talking to tower only no ATC vectors. Our own NAV again training. This is real world where radar is not available. I could go into detail but even our base a non towered airport with two RNAV approaches 30 NM from MEM ARTCC can not give vectors only advise. I know I visited the ARTCC and talked to them.

There is a RWY FIX in the data base to trigger the missed. The published missed can be flown by GPS (I assume) although holding fix is a radial and DME. I assume the GPS RWY Fix could be used for missed, but timing would be required here to be totally legit. Obviously ILS (with GS which we don't have) it would be DA for missed.

We did an alternate missed and left the area back to base. We did have good lesson on DME arc, timing, 5T's, missed and nice RNAV LPV to base airport (non towered VFR own Nav. I either give student ATC instructions (as ATC would and expect readback from student) or clear them for approach, monitoring ATC and CTAF. We do file but I don't need or want to POP UP with Approach in VFR doing approaches to a rural area. If I was training in LA airspace it would be with approach.

My question was is the DME OK for LOC approach with DME fixes. Keep in mind DME required comment in IAP plate. Not withstanding the cycling issue and GARMIN note when you select it warning this is for reference only (not sure or recall exact verbiage). The answer is YES... all agree. I am sure this is pretty universal, but does anyone know exceptions.

Second is the cycling of waypoints in GARMIN. I do know about flyby and flyover. So it is possible I should have left it alone and the waypoint would have cycled if I gave it time. I have to figure that out. I get different answers about the 430 automatically switching the Stby LOC Freq into active and going from GPS to VLOC mode automatically.

As far as most pilots prefer vectors. That is not relevant. This is training. I fly for a living I am very familiar with vectors. Sure vectors are great, but my home base is 32NM from MEM ARTCC and MEM Approach. They can not give vectors. They can turn you yes, but can not clear you for approach, only help. You are required to do own NAV. How do I know? I visited ARTCC and talked to them and this topic came up. They just don't have coverage that low to monitor your approach. They will tell you to switch to CTAF and call this Freq if you miss... Radar is not assured at low altitude. I was surprised but that is a fact.

A follow up question is if an approach is not cycling, how do you recover? For example if holding at IF (hold instead of procedure turn), the ONLY way to get out of the hold and start the approach is CLEAR the hold. A direct to IF or FAF will cause problems for the 430... Please don't say select vectors. Again training and we need to do hold practice.

As @John Collins and @midlifeflyer have said, DME required and Radar required for procedure entry are two notes, independent of each other. It’s not an ‘or.’ Both are required as already described. You put “IT IS A TIMED APPROACH” in all caps. I assume that was in response to my post discussing timed approaches when I was wondering why there was an alternate missed approach approach procedure when it, and the published missed approach procedure are both based on the same Navaid. That is very unusual. Yes, the term timed approach is used to describe using time to identify the missed approach point. It has another meaning also. See AIM 5-4-10. Timed approaches are also referenced in FAR 91.175 (j). It is one of the instances where you may not do a Procedure Turn.

What you learned from your visit to Memphis Center verified my speculation on why there probably is an Alternate Missed Approach Procedure even though it is based on the same Navaid as the published one. They use it as a traffic management tool.

 

[midlifeflyer]

What you learned from your visit to Memphis Center verified my speculation on why there probably is an Alternate Missed Approach Procedure even though it is based on the same Navaid as the published one. They use it as a traffic management tool.

Yep. Sometimes there's a non-TERPS reason for something on an approach chart. "ATC REQUEST" is not an unusual note to find in the regulatory source (Form 8260-x) document

 

[luvflyin]

Yep. Sometimes there's a non-TERPS reason for something on an approach chart. "ATC REQUEST" is not an unusual note to find in the regulatory source (Form 8260-x) document

6. CHANGED MA FROM “CLIMB TO 1000 THEN CLIMBING LEFT TURN TO 2200 DIRECT MKL NDB AND HOLD.” TO “CLIMB TO 1000 THEN CLIMBING LEFT TURN TO 2200 ON HEADING 230 AND MKL
VOR/DME R-254 TO SKOAL/MKL 12.00 DME AND HOLD.” - MERSY NDB DECOMMISSIONED AND ATC REQUEST.
7. ADDED CLIMB-IN-HOLD AND REMOVED “DME REQUIRED” FROM ALTERNATE MA. – UPDATED EVALUATION AND DME REQUIRED FOR ENTIRE APPROACH.
8. REMOVED PT INFO FROM LINE 1. - MERSY NDB DECOMMISSIONED AND ATC REQUEST

Didn't see anything that directly explained why there is an alternate though. But I think it's pretty clear why.

 

[FORANE]

Used to be a super busy flight school operating there. At one point it was like big city rush hour traffic.

 

[fly4usa]

There are so many things for me to say. Great stuff, but to the GNS430W does not come with GS receiver automatically. It is an additional charge the owner did not pay for. Tuning the LOC in you do not GS on the G5. There is no GS receiver because it cost $4000. It has a VOR/LOC receiver. No ILS possible.

The LOC approach is a timed approach. The 2.3 DME I-MKL is the VDP. Good to know because that allows you to land normally. The 1.2 DME is end of runway. The timed approach is 5.1 NM from MERSY, or about 0.1NM past end of runway. This is typical of non precisian timed approaches, if you don't see the runway about 1.5NM from end of runway and start towards to runway (if you have runway environment in sight) then you might not be able to land.

On the approach it was tuned, LOC, green, indicating correctly. It did switch to VLOC automatically. This is apparently a setting for AUTO VLOC. Thanks to person above who gave that nugget of info. I thought VLOC was always manual. The missed you (clear) suspend, always manual selection. Not sure why that is not automatic, but it assumes you have landed unless you tell it otherwise.

The comment about going DIRECT to waypoints in the approach may work or may not. I did go direct to MERSY. I think that was the issue. I know from first hand experience, holding at an IAP fix (RNAV LPV at home field), wanting to leave hold and start approach you CLEAR THE HOLD... Going direct to next waypoint will cause cycling issues. I know. This may have been the issue with the DME arc to final and OZZIE being a flyby. I should have waited longer before going direct to MERSY (and may have cycled but jumped the gun), or should have cleared the DME ARC which was still active. I will get another shot at it.

As far as being cleared for the DME arc keep in mind we are VFR, in Class E airspace, way outside towered class D talking to tower. We did not have to talk to anyone at that point. Called Tower 15 miles out telling what we wanted to do. They said report MERSY. It is all legal and safe. When a student is more up on procedures we file. And when the instructor figures out this particular approach. RNAV approaches all day. Even a VOR approach with a classic procedure turn, all good. This DME arc however did not go as planned. The approach went fine.

The GPS did not cycle. If I would have CLEARED the arc vs gone direct to I feel it would have worked. Doing Direct takes it out of approach mode (possibly). I will try again. Plane down for 2 weeks for annual. Thanks for the help. Thanks for the AIM Reference.

PS The Garmin trainer for 430 is obsolete and has not been updated in a long time and does not run on my computer. Also it is fairly limited in data base. HOWEVER there are 3rd party simulators (MSFS) that have a 430W. If you have a GTN650/750 there is support for trainers. With that said YOUTUBE has good Garmin videos.

 

[RussR]

@fly4usa -

Are you sure about what you have? The 430W, as far as I know, never had a "no GS" option. Even the Garmin website says it includes an ILS receiver with both localizer and glideslope. In your other thread you say it's a 420W with VOR and LOC, but a 420W doesn't have ANY navaid receiver, no ILS, LOC, or even VOR.

So I'm more than a little confused as to what you actually have. It's possible to have a 430W connected to a CDI with no GS needle, and therefore not "have" GS, but you mention having a G5, which does include a GS needle and not wiring the 430W GS output to it would be strange indeed.

Could it be that the 430W GS section is just broken and needs to be fixed?

 

[midlifeflyer]

PS The Garmin trainer for 430 is obsolete and has not been updated in a long time and does not run on my computer. Also it is fairly limited in data base. HOWEVER there are 3rd party simulators (MSFS) that have a 430W. If you have a GTN650/750 there is support for trainers. With that said YOUTUBE has good Garmin videos.

I wonder what you have and where you downloaded the trainer. There are two versions out there. The old one doesn't run in Windows since XP, but the later one works fine. I run it just fine on my 2 year old Windows computer. I have some avionics videos on YT and the GNS ones used the trainer. (Actually, I ran your approach on it.) And if you search around, you'll discover there are ways to update the database.

Be careful of the one in MSFS. I haven't looked at it but the ones in lower-end applications (including some FAA-approved Aviation Training Devices) tend not to be full-fidelity emulations. Not bad for the basics, but there are functions missing and not all functions work the same way.

 

[John Collins]

The GNS430W has a built in NAV and ILS GS receiver. The GNS400W does not have a Nav receiver or Com, just WAAS GPS receiver. The GNS420W has a Com unit and a WAAS GPS receiver. The aircraft may have one of the other two models. but if the GPS is truly a GNS430W, it has a GS receiver. If the aircraft has either the GNS400/GNS420, it is not legal to fly the ILS or localizer procedures.

 

[BillTIZ]

I did not read all of the responses, so someone may have already answered this.
The Garmin 430 will auto change from GPS magenta guidance to "green needles" about 3nm from the FAF. OZZIE is not the FAF, that is at MERSY 6nm from OZZIE, so I would expect magenta GPS guidance until about 3nm from MERSY.

Were you still getting magenta guidance from the arc to MERSY? if you did not pass within a certain distance of OZZIE, I would not expect the system to show progress past OZZIE.

One "technique" when turning from the ARC to the inbound course and still outside the FAF is to select Vector to Final on the Garmin navigator. Instant green needles and guidance to the FAF along the Final Approach Course.

Another factor to consider if using an autopilot. Know your system. The early Cessna G1000 with the KAP140 autopilot, the KAP140 will revert to "roll/hdg" mode when the nav source is changed. So if on the arc, when the G1000 reverts from magenta gps guidance to green localizer needles, the KAP140 will drop out of APCH mode and revert to ROLL/HDG. Be prepared to reactivate APCH mode on the KAP140. Same thing will happen if you manually change from GPS to CDI mode.

 

[flyingron]

Yep, it defeats the whole purpose of having an alternate missed approach. I have no idea why it was done this way.

"Operational reasons." The published missed approach procedure really only gets used in lost comm situations.

 

[midlifeflyer]

"Operational reasons." The published missed approach procedure really only gets used in lost comm situations.

I've flown the published missed whenever I have not received custom ATC instructions. It has happened a number of times, particularly on approaches to nontowered airports.

 

[flyingron]

I've flown the published missed whenever I have not received custom ATC instructions. It has happened a number of times, particularly on approaches to nontowered airports.

I'm not talking approaches in general, just the one given above.