Approach plate question

proxima3003

Well-Known Member
An instructor friend of mine asked a question on an approach plate into KRMN, ILS 33 and I couldn't help him. The question is:

How do we fly the teardrop procedure turn? (From HIGAP to AFUWY). He has flown the approach and tried both standard and half-standard rate turns, none of which put him on the LOC inbound. There are no lead radials that I could see. I know you can do a GPS overlay and fly the magenta, but this is an ILS only plate.

The 10NM scale ring on the plan view threw me off as well. The profile view shows the PT inside 10NM, while the plan view depicts it outside. So whats up?

ils33rmn.jpg
 
Even more strange is that is states PT NA in the profile view

Ryan Davis - Assistant Chief Flight Instructor - CFI / CFII / MEI / AGI / IGI / ATP - Captain BE90
 
Even more strange is that is states PT NA in the profile view


That's because it's not a procedure turn. There is one, and only one, IAF (BRV) and you fly the full procedure including the arc.

You're not tracking outbound on the inbound course for a reversal, you're using a separate radial for the outbound leg as a part of the full procedure.

Using the 1° = 1nm at 60nm rule of thumb, 27° at 10nm is roughly 27/6 = 4.5nm between HIGAP and AFUWY, which would be a 2.25nm radius.

A standard rate turn at 200kts will be about a 1.25nm turn radius.
A standard rate turn at 100kts will be about a 3/4 mile turn radius.

Basically, if I were flying this, upon passing HIGAP I'd start a standard rate turn and stop with a 30° intercept to the localizer. The MSA for the east side is 1800' so I'm not worried about hitting things at my 3,000' until WALOX.
 
That's because it's not a procedure turn. There is one, and only one, IAF (BRV) and you fly the full procedure including the arc.

You're not tracking outbound on the inbound course for a reversal, you're using a separate radial for the outbound leg as a part of the full procedure.

Using the 1° = 1nm at 60nm rule of thumb, 27° at 10nm is roughly 27/6 = 4.5nm between HIGAP and AFUWY, which would be a 2.25nm radius.

A standard rate turn at 200kts will be about a 1.25nm turn radius.
A standard rate turn at 100kts will be about a 3/4 mile turn radius.

Basically, if I were flying this, upon passing HIGAP I'd start a standard rate turn and stop with a 30° intercept to the localizer. The MSA for the east side is 1800' so I'm not worried about hitting things at my 3,000' until WALOX.

Sorry @rframe, but I can shoot some holes in your math above (not that I would do all that math in flight, I'm not a trig whiz).

First: as you have mentioned, the pilot will fly two separate radials on this approach (BRV R-122 out and I-RMN LOC inbound). These are not 27 degrees apart as they originate in two separate locations . So the the distance you calculated for HIGAP to AFUWY is incorrect. I don't know how to get that distance mathematically, but if you simply plot these waypoints in ForeFlight, they are 6nm apart.

Second: using the formulas from the PHAK (100kts/10+7 to get a bank angle of 17 for std rate turn. (100kts^2)/(11.56*tan(17 bank)) to get a 1.1nm turn diameter for 100kts. Which means you come up 4.9nm short if you just do a std rate turn. Even if you fly a rough 300 heading (the 30 degree intercept you mentioned), you will intercept the LOC way after WALOX. (Used ForeFlight to confirm that :)) Missed approach at that point.

Conclusion: unless you are flying a citation, a std rate (even half) won't cut it. Good idea though.
 
How is AFUWY identifyed as a fix?
That's an important question and an important point. (AFUWY) — don't forget the parenthesis — is a computer navigation fix for RNAV GPS boxes, not a "real" fix. It has the same purpose as the CNFs appearing on simple VOR approaches where the VOR is on-airport.

The importance of your point is that it answers @proxima3003's question of how you fly the approach without GPS. You forget about (AFUWY). There's no requirement to stay withing 10 NM. The procedure simply tells you to fly the BRV R122° to HIGAP and turn right to intercept the localizer inbound.
 
If you had DME you could fly a 10DME(BRV) arc from HIGAP to AFUWY. Simply turning right at HIGAP, well on what heading? You don't want to intercept the localizer at 90 degrees. This approach seems like it invites the pilot to kinda do whatever for the course reversal. I mean if you have a GPS or DME it's easy enough, but if you're /U like you should be able to be for this approach... it's weird.

Anyone have the Jepp?
 
Simply turning right at HIGAP, well on what heading?

Exactly the same way as you would if it were a hold.

Start turning toward the inbound course. Make the localizer the active navaid.

If you get within 30° of the inbound course without an intercept, stop turning until you do..

IMO, this is a simple, straightforward procedure that folks are trying to over-complicate. The only real potential complicating factors are misunderstanding what a CMF and the 10 mil reference ring are.
 
Exactly the same way as you would if it were a hold.

Start turning toward the inbound course. Make the localizer the active navaid.

If you get within 30° of the inbound course without an intercept, stop turning until you do..

IMO, this is a simple, straightforward procedure that folks are trying to over-complicate. The only real potential complicating factors are misunderstanding what a CMF and the 10 mil reference ring are.
I thought it was demonstrated earlier that at 100 knots you'd be inside the FAF before intercepting the localizer... which when I re-read appears not to be the case. Ya, no problem here.
 
That's an important question and an important point. (AFUWY) — don't forget the parenthesis — is a computer navigation fix for RNAV GPS boxes, not a "real" fix. It has the same purpose as the CNFs appearing on simple VOR approaches where the VOR is on-airport.

The importance of your point is that it answers @proxima3003's question of how you fly the approach without GPS. You forget about (AFUWY). There's no requirement to stay withing 10 NM. The procedure simply tells you to fly the BRV R122° to HIGAP and turn right to intercept the localizer inbound.

That is what I was starting to believe, I kept thinking "fly it like a DME arc, Fix to Fix." I was curious why it was not Identified by a cross radial or DME, that makes sense, as there is no other way to ID that (fix) :). I have not seen a fix like that for some time. I believe that clears it up, set up your course needle (LOC), pick a decent intercept to hit 10.4 DME on the LOC freq and fly to it....I fail to understand why bank angle has been made great importance here.
 
I've been asking around about this one since I saw this topic. I found out that in real life you will never get the full procedure for this approach. It's too close to the restricted areas, DC SFRA and KIAD. It's mostly an academic exercise to figure out what this approach plate means. Nobody seems to know though.. I'm mostly confused by why the turn towards the course is shown as being past HIGAP in the plan view, but happening before HIGAP in the profile view. Then there's the mysterious "Procedure turn NA"
 
I found out that in real life you will never get the full procedure for this approach. It's too close to the restricted areas, DC SFRA and KIAD. It's mostly an academic exercise to figure out what this approach plate means.

In "the old days" loss of radar and loss of communication were far more prevalent. We tend not to think much of that in today's environment, but the approach still has to support that possibility.
 
In "the old days" loss of radar and loss of communication were far more prevalent. We tend not to think much of that in today's environment, but the approach still has to support that possibility.
I've been flying in areas of poor to no radar coverage(at approach altitudes) long enough now that the only way I even think about an approach is the full procedure. There are exactly 4 airports we go to that will give vectors to final. Out of hundreds. I guess it's still the "old days" out west. At least until ADS-B is mandatory.
 
I've been flying in areas of poor to no radar coverage(at approach altitudes) long enough now that the only way I even think about an approach is the full procedure. There are exactly 4 airports we go to that will give vectors to final. Out of hundreds. I guess it's still the "old days" out west. At least until ADS-B is mandatory.

I recall talking to a Hornet driver while I was working on my IR, he told me "Those (approach plates) are for lost communications." No instructor ever told me that, just explained that I am most likely to get vectors. Puts in perspective, really.
 
I recall talking to a Hornet driver while I was working on my IR, he told me "Those (approach plates) are for lost communications." No instructor ever told me that, just explained that I am most likely to get vectors. Puts in perspective, really.
I chuckle when we get a "cleared approach" 100 miles from the IAF while still in cruise (at 2am) and people are like... uh what do I do now?
 
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