Question re Approach

Llewtrah381

Llewtrah381

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Llewtrah
The ILS 30 at KJEF has the usual table of mins for the different approach options but right below it is another table called “WAPGY Fix Minimums”. In that one, there are no mins for the ILS but the S-LOC-30 mins are actually 200 feet lower than the table above (circling mins are the same). What’s that table for and when does it apply? Is it when you’re able to identify WAPGY, via DME or GPS? Given that “ADF or DME (is) required”, it would seem like that would always be the case anyway (unless you really just had ADF and no DME or GPS, I guess).

8D8C8582-80EB-4433-BDA5-6F025309D7FD.jpeg
 
Yes, I'm not a TERPS expert like some here, but you're exactly right:

If you only have a localizer needle and an ADF, you can't identify WAPGY and therefore the MDA is 1080’. If you have DME or GPS and therefore can identify WAPGY (and/or presumably if ATC can inform you when you're passing WAPGY via radar, though I have no experience in that way of doing things) you can descend to 880’ after passing it (until reaching the missed approach point).

My speculation is that the WAPGY minimum crossing altitude of 1080 on the profile view matching the MDA of 1080 if you can't identify WAPGY is no accident -- there is some obstacle around there that requires 1080' in order to clear by TERPS. If you can identify WAPGY, you know when you've passed it, and can descend further. If you can't, you can't. That's also why it doesn't affect the ILS: If you are on glideslope, the obstacle is no factor. And circling approach isn't affected because its minimum is higher anyway.
 
Llewtrah381 said:
The ILS 30 at KJEF has the usual table of mins for the different approach options but right below it is another table called “WAPGY Fix Minimums”. In that one, there are no mins for the ILS but the S-LOC-30 mins are actually 200 feet lower than the table above (circling mins are the same). What’s that table for and when does it apply? Is it when you’re able to identify WAPGY, via DME or GPS? Given that “ADF or DME (is) required”, it would seem like that would always be the case anyway (unless you really just had ADF and no DME or GPS, I guess).

View attachment 97700
Click to expand...

That’s it. That 959 foot obstruction on the Chart tells the story. You may run across an Approach someday where the ‘Stepdown’ is an Intersection. If so you’ll see a Dual VOR receivers required note.
 
mcmanigle said:
If you only have a localizer needle and an ADF, you can't identify WAPGY and therefore the MDA is 1080’.
Click to expand...
If you only have a localizer needle and an ADF, how do you identify the MAP? Seems like there should be a timing table on the left that's missing.
 
asicer said:
If you only have a localizer needle and an ADF, how do you identify the MAP? Seems like there should be a timing table on the left that's missing.
Click to expand...

Yeah. FWIW the NDB is out of service and DME or suitable RNAV is required so timing for the MAP is not an issue. But it should be on the Chart. Unless the NDB has been out for a long time. The Chart Amendment date is 12Oct17. Here’s the Jepp Chart. It has the timing table.

upload_2021-6-27_2-39-48.png
 
asicer said:
If you only have a localizer needle and an ADF, how do you identify the MAP? Seems like there should be a timing table on the left that's missing.
Click to expand...
Yep. It's missing. The NOTAM means it no longer matters but it's missing.

(I guess you could create your own timing table if you were so inclined. It's just basic Time=Distance/Rate.) Edited to reduce from warp speed @dmspilot.
 
Last edited:
mcmanigle said:
... and/or presumably if ATC can inform you when you're passing WAPGY via radar ...
Click to expand...
Just an FYI, if a fix is able to be identified by ATC radar, it'll be annotated on the chart like this:
CBAFE612-D341-4849-9317-4865C4143892.jpeg


Also, I'm not going to try and find it, but I don't think radar can be used to identify points inside the FAF/FAP (but don't quote me on that one.)
 
midlifeflyer said:
Yep. It's missing. The NOTAM means it no longer matters but it's missing.

(I guess you could create your own timing table if you were so inclined. It's just basic Time=Distance/Time.)
Click to expand...
Based on the length of the NOTAM, it appears the LOM will be returned to service. Then, the timing table will apply. FAA charting screwed up.

This statement on source triggers the timing table:

JEF Timing Source.jpg
 
luvflyin said:
That’s it. That 959 foot obstruction on the Chart tells the story. You may run across an Approach someday where the ‘Stepdown’ is an Intersection. If so you’ll see a Dual VOR receivers required note.
Click to expand...
Nope. It is an 829' tree.
MO_KJEF_ILS OR LOC RWY 30_A6_S-9.jpg
MO_KJEF_ILS OR LOC RWY 30_A6_F-5.jpg
 
The tree must have grown:


JEF 1/2592 Procedure 05/07/2021 1154 05/07/2023 1153EST IAP JEFFERSON CITY MEML, JEFFERSON CITY, MO. ILS OR LOC RWY 30, AMDT 6... S-LOC 30 WAPGY FIX MINIMUMS: MDA 920/HAT 371 ALL
CATS, VISIBILITY CATS C/D 5/8. 2105071154-2305071153EST
 

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Sluggo63 said:
Just an FYI, if a fix is able to be identified by ATC radar, it'll be annotated on the chart like this:
View attachment 97710


Also, I'm not going to try and find it, but I don't think radar can be used to identify points inside the FAF/FAP (but don't quote me on that one.)
Click to expand...

From TERPS:
2-9-4. Fixes Formed By Radar. Where ATC can provide the service, ASR may be used for any terminal area fix. PAR may be used to form any fix within the radar coverage of the PAR system. Air Route Surveillance Radar (ARSR) may be used for initial approach and intermediate approach fixes. Coordinate with the appropriate ATC facility before establishing a radar fix to ensure the facility agrees to provide the radar fix service.

I have never seen a Step Down Fix on the Final Approach Segment published as a Radar Fix.
 
MauleSkinner said:
Check out the LOC 27 at KMEM.
Click to expand...
It is unusual because it all has to be certified and flight inspected so the tower can call it out on their BRITE Display. The earlier radar fixes are usually called out by approach control.
 
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