KIWA Approach Plate Question

[kellwolf]

10 mi ring provides obstacle clearance for the PT.

[averyrm]

It says "Remain within 10nm." And if you only have the min. nav, use time to figure it out.

[FLpilot]

Yes there are approaches that state to remain within 10nm, but not all. Take for instance the approach in question.

http://www.myairplane.com/databases/.../00074I30C.PDF

I have never read in the AIM that this is a hard limitation, nor that obstacle clearance is guaranteed inside of 10nm. It makes perfect sense, yet I've never come across it. Anyone got a ref?


Edit: Disregard. It is late and obviously I can't read worth a crap tonight.

[averyrm]

If you read in the profile view, it states "Remain within 10 NM"

[Flysher]

Originally Posted by FLpilot

Anyone know where it is published that the 10nm ring is a limitation? I am pretty sure that it only means that anything inside it is "to scale" and anything outside is not. It is not a hard distance to remain within.

Also, how would you identify being outside of 10NM from SNOWL with only the minimum navs required for this approach?

yes you are correct. the 10 mile ring on the plan view is for scale purposes.

It also happens that most of the time the profile also says to stay within 10 miles for protection.

[meritflyer]

AIM 5-4-9

"Pilots should begin the procedure turn immediately after passing the procedure turn fix (SNOWL in this case). The PT must be executed within the distance specified in the profile view. The normal PT distance is 10 miles."

[FLpilot]

Ask and ye shall receive. Thanks!

[meritflyer]

SNOWL would be the PT fix correct? This may be a really stupid thought but I've never thought an intersection as a fix.

Ouch!

[averyrm]

yup.

[MikeD]

Originally Posted by meritflyer

Uhh.. you sure? Why would we care what the DME was outbound on the backcourse?

Correct me if I'm wrong, but are you saying you' fly outbound on the LOC (as course guidance) for the 45/180 course reversal back inbound? Then intercept the "front course" inbound?

Rest was covered regards the VOR course for the reversal and the actual LOC course being non-coincident.

Here's a quiz question for anyone. Anyone know the reason for the different missed approach instructions noted on the VOR/TAC approach plate here?


http://204.108.4.16/d-tpp/0609/00074VT30C.PDF

[TonyC]

Originally Posted by meritflyer

I have a question for y'all about the ILS 30C into KIWA -

On the Jepp plate, I notice that the 122 radial off IWA is shown as if it points to the back course and says 122* 4.9 5000.

Why does it show a VOR radial if you are to fly the LOC backcourse?

Correct me if I am wrong - You'd fly the backcourse at 4600' then once you have course guidance inbound after your PT you'd descend to 3000' for GS intercept.

Anyone know why that is? Why would we care how far SNOWL is from the VOR on the plan view? Why is that arrow (feeder route) there and what the heck does it mean?

AHHH!

I am confused

Look at the approach again, and ask yourself this question:

If the ILS Glideslope is NOTAMed out of sevice (OTS), how will I fly this approach? How will I define the Final Approach Fix (FAF)?



I believe the answer to your question will be found in that analysis.






.

[TonyC]

Originally Posted by MikeD

Here's a quiz question for anyone. Anyone know the reason for the different missed approach instructions noted on the VOR/TAC approach plate here?


http://204.108.4.16/d-tpp/0609/00074VT30C.PDF

Yes.







.

[meritflyer]

Originally Posted by MikeD

Correct me if I'm wrong, but are you saying you' fly outbound on the LOC (as course guidance) for the 45/180 course reversal back inbound? Then intercept the "front course" inbound?

Thats what I am saying. Track the LOC outbound for course guidance then execute your PT.

????

[casey]

Originally Posted by FLpilot

I have never read in the AIM that this is a hard limitation, nor that obstacle clearance is guaranteed inside of 10nm. It makes perfect sense, yet I've never come across it. Anyone got a ref?

TERPS

[meritflyer]

Originally Posted by TonyC

Look at the approach again, and ask yourself this question:

If the ILS Glideslope is NOTAMed out of sevice (OTS), how will I fly this approach? How will I define the Final Approach Fix (FAF)?

2 ways of defining SNOWL. 1- DME off IWA and 2- using the 025 radial off TFD.

[MikeD]

Originally Posted by TonyC

Yes.


.

Excellent. I figured you'd be one of the ones that'd know already, with your background. It's one of those interesting tidbits of info that's on the plate.

[meritflyer]

MikeD, isnt that how you'd execute the approach? Track outbound on the LOC for the course reversal?

[casey]

Originally Posted by MikeD

Excellent. I figured you'd be one of the ones that'd know already, with your background. It's one of those interesting tidbits of info that's on the plate.

i also know the answer to that one, but wont spoil it for you. No military background here though, just too much time on my hands.

Originally Posted by meritflyer

MikeD, isnt that how you'd execute the approach? Track outbound on the LOC for the course reversal?

fishing for the answer you want? Yes, fly the loc outbound to start the course reversal *but* fly the feeder to join the loc outbound. If you get solid usable nav signal from the loc outbound there shouldnt be a problem joining it (though the terps criteria for a loc/gs is not the same as a feeder). The reason for the feeder rather than just a straight up "fly the backcourse" is for a couple reasons. 1) you may not be able to navigate directly to the IAF to start the course reversal, 2) you cant navigate "direct to the loc antenna" and 3) the LOC is crazy sensitive at the antenna site.

The feeder is just to get you to join the loc outbound and to the procedure turn.

[MikeD]

Originally Posted by meritflyer

MikeD, isnt that how you'd execute the approach? Track outbound on the LOC for the course reversal?

If coming from IWA VORTAC, you'd need to track outbound on the IWA R-122 to 4.9 DME in order to get to SNOWL. SNOWL is defined off the VORTAC radial/DME, not off the LOC, as stated by the note next to the IWA VORTAC on the plan view. To be more specific, and looking at the profile and plan views, note that SNOWL is defined using IWA VORTAC (113.3/Ch80), and not I-IWA Localizer (110.15), since as mentioned before, the two are not coincident (VORTAC and LOC located in geographically different areas). Passing SNOWL, execute the 45/180 PT remaining within 10NM, unless you're Cat E where the PT is NA (because of no way to remain within 10NM with normal maneuvering). Inbound on the PT, you intercept the 303 LOC course inbound.

[fish314]

Alright Mike, I'm going to spill the secret...

There are different holding instructions for TACAN only aircraft in the plate that MikeD mentioned because TACAN only aircraft are prohibited from holding directly over the TACAN. This is because station passage for a TACAN is defined as when the DME stops decreasing....

...So, if you were to try holding over the TACAN, you'd have to STARE at the DME, and make your outbound turn as soon as the DME went from decreasing to increasing again. This could be pretty easy to miss. So they don't let you hold right over the TACAN...instead you have to hold using the VOR portion (because it has the To/From indicator) if you have one, or you have to hold at some other fix that isn't right over the station if you are really TACAN only.

[MikeD]

Originally Posted by fish314

Alright Mike, I'm going to spill the secret...

There are different holding instructions for TACAN only aircraft in the plate that MikeD mentioned because TACAN only aircraft are prohibited from holding directly over the TACAN. This is because station passage for a TACAN is defined as when the DME stops decreasing....

...So, if you were to try holding over the TACAN, you'd have to STARE at the DME, and make your outbound turn as soon as the DME went from decreasing to increasing again. This could be pretty easy to miss. So they don't let you hold right over the TACAN...instead you have to hold using the VOR portion (because it has the To/From indicator) if you have one, or you have to hold at some other fix that isn't right over the station if you are really TACAN only.

Excellent.

On a related note that you'll probably appreciate, RMI fix to fix's for me are still more of a WAG than any sort of skill.

[CapnJim]

Tower- "Cleared visual three-zero center.
Me- "Yeah, roger."

*splat*

"Welcome to Sheldon folks! Get the f' out!"

[TonyC]

Originally Posted by meritflyer

2 ways of defining SNOWL. 1- DME off IWA and 2- using the 025 radial off TFD.

This is true. If you have two radios, you can tune one to the ILS, I-IWA (110.15) and the other to... well, let's look at the options:

Willie VORTAC (113.3), where we can view the DME in increments of 0.1 NM

-or-

Stanfield VORTAC (114.8), where we can read radials. At 27.1 NM from TFD, one degree on the guage equals roughly one half mile. Perhaps your instruments can be off by 4 degrees and still be considered within tolerances. That would represent, at 27.1 NM from TFD, approximately 2 NM. Of the 4.4 NM between SNOWL Intersection and the runway, you could conceivably give up 2 NM before you even begin.



But what if you only have ONE radio. Could you still do this? If yes, how?





.

[meritflyer]

Switichin em back and forth.

[MikeD]

Originally Posted by meritflyer

Switichin em back and forth.

I'd highly caution against that. You've already intercepted the glideslope and are tracking inbound on the final segment. Once inside the FAF, one receiver must always be tuned to the facility providing final approach guidance.

I bet the crew of IFOR 21 would have alot to say about cross-tuning on final, if they could.

.