Instrument App Fix ID Legalities

[tgrayson]

I think I'll just wait and see what you find out from the Flight Procedures Branch

Sorry for the delay on this. The Flight Procedures person who had promised to research my question apparently forgot all about it and I wasn't able to follow up for a while.

I spoke with two people at Flight Procedures, neither one of whom was able to give satisfying answers. The first guy assured me that EGORE was identifiable as an intersection, saying that anyone who couldn't see that "ought not to be flying", but then retracted his statement when confronted with the fact that the FAF is identified only via DME (hence the VOR/DME), although it's the same fix. He claimed that the lack of an "INT" in the name in the planview was meaningless because US Government cartographical standards prohibited the inclusion of that in the planview, a statement which was clearly incorrect. He also acknowledged that the FAA database identified the fix as only be defined via DME from Manchester. Zero information here.

He passed me off to the guy who actually has the territory for the airport. This specialist was careful to avoid saying the approach was in error, but said if it were looked at closely, the feeder route from Gardner might be NOTAMed out of service, due to the challenge of identifying EGORE without an intersection being defined. He defended the current design by saying it was pretty old and might not be designed the same way today; plus, it's probably going to be replaced soon by an RNAV approach. He said he'd pass the issue up the chain.

After these conversations, I also spoke with a NACO guy. He explained that the thin R-104 radial line is indeed used to show the radial used to define a fix, but in this case, that fix was the stepdown fix on the feeder route. Why that fixed needed its own line rather than using the feeder route line was a mystery to him. He pointed that that *most* of the time, when a radial is used to identify an intersection, it will go all the way through the fix position, or at least right up to it. On some rare occasions, chart clutter may require that the line stop well short of the fix. He also pointed out that another clue was the small, horizontal line used to denote EGORE—this is used to depict a DME-only fix, another hint that no intersection is defined. As for the "EGORE INT" in the profile view missed approach icons, he agreed that was an error and he'd see that it was removed.

Bottom line: EGORE is not an intersection and the feeder route probably shouldn't be there because you can't identify EGORE legally when flying that route.

 

[ghogue]

...................

Bottom line: EGORE is not an intersection and the feeder route probably shouldn't be there because you can't identify EGORE legally when flying that route.

tgrayson,

Thank you for the update. You went the extra mile in checking on this, but it's always a bit unsettling to me when several people who should know the answer, all have different ones and often incorrect, as well. I've been through that on several occasions when working with folks at the FAA and TSA. More than once I've had to do the research and instruct them on the proper way.

I think I'll just watch and see if the chart is revised.

gary

 

[fish314]

I've heard some instructors teach that if the thin line doesn't go all the way through the fix then you are not legally allowed to use that crossing radial to define the fix.

Unfortunately, I can't find anything written anywhere that backs that up, and Tgrayson's NACO guy seems to confirm that this is true "MOST" of the time, but not "all" the time. Which is the same as saying that it isn't true at all, because how can anyone know what the exceptions are?

So I just use that as a rule of thumb. If the line goes through the fix, I can use the radial to define the fix. If it doesn't, I probably can't. I'd love to find an actual reference somewhere, though, becuase it makes sense that not every crossing between two radials would be precise enough to base a fix off of. For example, if the two navaids in question are spaced pretty far from each other, or if the two radials in question do not have a big enough angle between them. But at the same time, I'm not going to be able to TERPs every approach myself.

 

[tgrayson]

But at the same time, I'm not going to be able to TERPs every approach myself.

No, and that's the frustrating thing...some of these TERPS guys start throwing in this "I can see that the angle is within parameters and can do X", without stopping to consider that pilots don't have access to that knowledge, only the plate in front of them. Plus, sometimes there are other reasons a radial might not work, such as problems during flight inspection. We need definitive rules on how to interpret the chart and we don't have them. Even the Chart User's Guide is woefully inadequate. Sometimes TERPS knowledge does help in recognizing the clues that exist on the chart, but not always. Fix determination is probably the biggest problem; the actual forms used by the FAA to design the approach are very precise, but that information sometimes gets lost during the chart design.

 

[Bernoulli Fan]

Bottom line: EGORE is not an intersection and the feeder route probably shouldn't be there because you can't identify EGORE legally when flying that route.

Thanks for checking up on this.