Feeder route question

flyingron said:
The fact that ELWHA is a compass locator seems to be spurious to the approach other than if you muff the intercept of the localizer coming from CVV or JIGEB badly, you can find out which side of the marker you're on.
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The Feeders from JIGEB and CVV are to ELWAH, CL frequency 515. They are not DR legs to intercept the Localizer. It would say HDG if so. In the case of JIGIB it's self explanatory. You can't fly radials from a Fix. Fixes don't have radials. I tried to post a screen shot of the Gov Enroute Chart but it was to large for the server. Have a look at it. It tells the story. It looks like WATTR used to be Feeder Fix. I'd like to see the history of this Approach.

https://nfdc.faa.gov/webContent/content8260/WA_JIGEB_REV3.pdf
Note the Fix Makeup Facilities
 
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Palmpilot said:
The trouble with the IAF at TOU is the note that says you can't use it if you're coming to it on V4. That is currently the only victor airway that goes to TOU!

When I brought up this problem on the old AOPA forum, Ron Levy expressed the opinion that it was OK to fly the CVV feeder routes without ADF or GPS.
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Yup. You'd have to arrive at TOU some other way. If you were cleared there via V4 you'd have to request and and get a turn in holding. To the west on the 260 radial would make it nice n easy. I'm kinda surprised they don't have a hold charted there. I agree with that Ron guy. But it's being 'OK.' It's not, how shall we say, legal.
 
luvflyin said:
Yup. You'd have to arrive at TOU some other way. If you were cleared there via V4 you'd have to request and and get a turn in holding. To the west on the 260 radial would make it nice n easy. I'm kinda surprised they don't have a hold charted there. I agree with that Ron guy. But it's being 'OK.' It's not, how shall we say, legal.
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He thought it was legal. :dunno:
 
luvflyin said:
The Feeders from JIGEB and CVV are to ELWAH, CL frequency 515. They are not DR legs to intercept the Localizer. It would say HDG if so. In the case of JIGIB it's self explanatory. You can't fly radials from a Fix. Fixes don't have radials. I tried to post a screen shot of the Gov Enroute Chart but it was to large for the server. Have a look at it. It tells the story. It looks like WATTR used to be Feeder Fix. I'd like to see the history of this Approach.

https://nfdc.faa.gov/webContent/content8260/WA_JIGEB_REV3.pdf
Note the Fix Makeup Facilities
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Never said they were DR legs. I made the error of assuming since JIGIB and CVV showed the same bearing that the former was on the 243 radial of CVV. That's off by a few degrees, it's on the CVV 247 radial
 
flyingron said:
Never said they were DR legs. I made the error of assuming since JIGIB and CVV showed the same bearing that the former was on the 243 radial of CVV. That's off by a few degrees, it's on the CVV 247 radial
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Gotcha.
 
luvflyin said:
If ya wanna see an Approach with a DR Leg, look at the ILS Rwy 11 at KSBP. Note how ya get from FRAMS to the Localizer
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He didn't say anything about using a DR leg, as I recall.
 
Palmpilot said:
He didn't say anything about using a DR leg, as I recall.
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You couldn't have a DR leg on this Approach anyway. First of all they don't apply to Feeder Routes, just Initial Approach Segments, you'd have to make JIGEB an IAF to do it. Even then it wouldn't work. They can't be longer than 10 miles and the angle of intercept can't be less than 45 degrees. But it sounded like what he was saying is using the radial from CVV to intercept the Localizer. The more I think about it I'm not sure I'd agree it is 'Ok' like I said above. 38 miles and only 26 degrees. +/- 6, 4.5 or 4 degrees error, pick yer poison, is going to be a pretty wide swath along the Localizer where you might intercept it.
 
luvflyin said:
You couldn't have a DR leg on this Approach anyway. First of all they don't apply to Feeder Routes, just Initial Approach Segments, you'd have to make JIGEB an IAF to do it. Even then it wouldn't work. They can't be longer than 10 miles and the angle of intercept can't be less than 45 degrees. But it sounded like what he was saying is using the radial from CVV to intercept the Localizer. The more I think about it I'm not sure I'd agree it is 'Ok' like I said above. 38 miles and only 26 degrees. +/- 6, 4.5 or 4 degrees error, pick yer poison, is going to be a pretty wide swath along the Localizer where you might intercept it.
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I finally found where I saved the thread, and yes, that is what he was saying.

He also said that if you know your VOR receiver is four degrees off, you should be making a correction to your OBS setting so you will be on course.
 
Palmpilot said:
I finally found where I saved the thread, and yes, that is what he was saying.

He also said that if you know your VOR receiver is four degrees off, you should be making a correction to your OBS setting so you will be on course.
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How did he say he knows which VOR is the correct one, assuming checking one vs. the other? Gee, sometimes I miss him. ;)
 
dtuuri said:
How did he say he knows which VOR is the correct one, assuming checking one vs. the other? Gee, sometimes I miss him. ;)
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He said, "if you use it routinely (as you would if you don't have a GPS), you should know your VOR is off and by how much. These things don't just suddenly pop up with a 4 degree error."

I was flying a rental plane on the trip where I encountered this problem, but I probably did a dual VOR check at my home field before departing. Since the bearing from Woodside VOR is known (and published), I would have known if the two VOR receivers were both off in the same direction by an unusual amount. Also, the plane had a VFR GPS installed, and if I had flown the approach, I would have monitored it to make sure the IFR-legal avionics weren't leading me astray and into the nearby cumulo granitus. As it was, I didn't think it would be legal to fly it without an ADF or an IFR GPS, which is why I ended up making the flight in marginal VFR conditions below the smoke layer (and over the water).
 
Palmpilot said:
Since the bearing from Woodside VOR is known (and published), I would have known if the two VOR receivers were both off in the same direction by an unusual amount.
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If it wasn't via a published ground checkpoint, would you still apply the noted correction?
 
dtuuri said:
If it wasn't via a published ground checkpoint, would you still apply the noted correction?
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I don't know; maybe. I haven't had to make that decision.

I did once have a controller complain that I was a few degrees off of a victor airway north of Portland, OR. I was showing on course, so I adjusted my position according to his input and adjusted the OBS to recenter the needle.
 
Palmpilot said:
I don't know; maybe. I haven't had to make that decision.

I did once have a controller complain that I was a few degrees off of a victor airway north of Portland, OR. I was showing on course, so I adjusted my position according to his input and adjusted the OBS to recenter the needle.
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It's been a good "academic" discussion, IMO. I think the OP got her money's worth. It's all about using good judgment. The more you know, the more you need to worry about.
 
Re: POAdeleted Ron Levy

Palmpilot said:
...

He also said that if you know your VOR receiver is four degrees off, you should be making a correction to your OBS setting so you will be on course.
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I can't seem to let go of this. Where is there any FAA guidance that says this should be done? My understanding is the 4° is a "permissible error". I don't know that trying to correct a Victor airway or VOR approach course with the error found during an accuracy check is allowable or even smart. If it was expected, you'd think it would be published somewhere like FAA training manuals do for compass deviation. Do VOR radials always have exactly one degree separating them or can there be a tolerance which can accumulate resulting in course centerlines other than the theoretical for a given siting location? I don't know the answer, so I never applied the correction Levy said should be made. Maybe somebody with VOR maintenance experience will see this and opine?
 
dtuuri said:
Re: POAdeleted Ron Levy

I can't seem to let go of this. Where is there any FAA guidance that says this should be done? My understanding is the 4° is a "permissible error". I don't know that trying to correct a Victor airway or VOR approach course with the error found during an accuracy check is allowable or even smart. If it was expected, you'd think it would be published somewhere like FAA training manuals do for compass deviation. Do VOR radials always have exactly one degree separating them or can there be a tolerance which can accumulate resulting in course centerlines other than the theoretical for a given siting location? I don't know the answer, so I never applied the correction Levy said should be made. Maybe somebody with VOR maintenance experience will see this and opine?
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I don't know the answers either. Ron posts on "The Pilot's Place" forum and the new AOPA "forum" if you want to ask him.
 
dtuuri said:
Where is there any FAA guidance that says this should be done? My understanding is the 4° is a "permissible error". I don't know that trying to correct a Victor airway or VOR approach course with the error found during an accuracy check is allowable or even smart. If it was expected, you'd think it would be published somewhere like FAA training manuals do for compass deviation.
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Yes, that idea makes me uncomfortable as well. What if you're 4 degrees off, do some math in your head for a correction but accidentally do it backwards because you've got other stuff going on? Well, now you're 8 degrees off and you may have used up all of the margin that is provided and go splat. Especially since you don't know if it's the VOR itself or the receiver. I'm not sure what the maintenance schedule is for VORs, but I'm sure they have some level of drift - Is the FAA readjusting them often enough to ensure that they're always within a degree? I kinda doubt it. And even if they are, it's quite possible that the next VOR will give you different results.

Do VOR radials always have exactly one degree separating them or can there be a tolerance which can accumulate resulting in course centerlines other than the theoretical for a given siting location? I don't know the answer, so I never applied the correction Levy said should be made. Maybe somebody with VOR maintenance experience will see this and opine?
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I don't have any VOR maintenance experience, but I've learned a thing or two so I'll tell you this: There is NOT "one degree separating them." There aren't 360 discrete VOR radials, the system works via a pair of signals and your receiver is basically an analog phase comparator. When you tune a "radial" you are almost certainly not exactly centered on the 176 radial for example, you're probably on the 176.426851 or some such - There are infinite radials. Does it matter? Not really, with 4 degrees of tolerance allowed for.
 
According to Table 4-1 of FAA Order 8200.1D, the flight inspection interval is "540 days for facilities (VOR or TACAN of a VORTAC) which support a SIAP or receiver checkpoint. An alignment orbit is required every 1,080 days for all facilities." How fast they drift, I don't know, but 540 days is also the interval for SIAPs themselves.

https://www.faa.gov/documentLibrary/media/Order/8200.1D_USSFIM_with_CHG_1.pdf
 

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flyingcheesehead said:
Yes, that idea makes me uncomfortable as well. What if you're 4 degrees off, do some math in your head for a correction but accidentally do it backwards because you've got other stuff going on? Well, now you're 8 degrees off and you may have used up all of the margin that is provided and go splat.
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That right there is probably the best reason not to add in the VOR error. Besides, if it ever became accepted practice examiners would feel obliged to make tests even tougher.
 
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