ESTABLISHED on a DME ARC ?

[TonyC]

"Maintain Five thousand until established, you're cleared the ______ approach."

Established on a localizer... I got it

Established on a VOR course... I got it

Established on an NDB course... I got that, too

But what if the segment of the published approach in question is defined by a DME ARC?

What constitutes "Established on a DME ARC"?

I've got loads of info from TERPS regarding obstacle clearance, criteria for building the approach, etc., and I've got plenty of OPINIONS about what constitutes "established." Does anyone have a documentable "correct" answer, i.e., one with a reference?

Your help is appreciated

 

[Andy Neill]

The Instrument Flying Handbook, AC61-27C, Revised 1980, Chapter 8, pp 142-145 describes the procedure to intercept and fly a DME Arc but is silent as to what constitues "established" on a DME Arc.

The PTS says that a DME Arc must be flown within 1 nm of the target value.

In the absence of more definitive guidance, I would say that I am established on a DME arc when I begin my intercept turn onto the arc such that I would roll out on the specified value AND I am within 1 nm of the specified value (whichever comes later). I guess that constitues another opinion. Sorry I could not find anything more definitive.

 

[midlifeflyer]

"Maintain Five thousand until established, you're cleared the ______ approach."

Established on a localizer... I got it

Established on a VOR course... I got it

Established on an NDB course... I got that, too

But what if the segment of the published approach in question is defined by a DME ARC?

What does it mean in those other cases? (the ones you "got"?)

 

[The FNG]

"Established" on anything means you've had your needle, CDI, OBS, CDB, or whatever CENTERED at some point, then remain within the lateral or vertical boundaries. If you were to intercept and fly an ILS 1/2 dot above/below the GS the whole way down you were never established. If you were to fly the entire DME arc offset 1 mile you would have never been established. Same thing with a PT inbound, you don't let down just because you're within the lateral boundaries. You let down once your needles are centered then remain within the lateral boundaries.

 

[Singlecoil]

"Established" on anything means you've had your needle, CDI, OBS, CDB, or whatever CENTERED at some point, then remain within the lateral or vertical boundaries. If you were to intercept and fly an ILS 1/2 dot above/below the GS the whole way down you were never established. If you were to fly the entire DME arc offset 1 mile you would have never been established. Same thing with a PT inbound, you don't let down just because you're within the lateral boundaries. You let down once your needles are centered then remain within the lateral boundaries.

Something tells me you get into this discussion often with the people you fly with. Course alive on a procedure turn on a VOR or ILS/LOC means you can let down. For NDB's it is within 10 degrees of the final approach course.
There are times you might want to fly an ILS a dot high the whole way down, like when you are following a heavy. That is perfectly legit.
Established means you are within the lateral boundaries, centered or not.

 

[cvsfly]

Also on a DME Arc established as part of the approach means according to the approach plate. If you are intercepting a published arc before the depicted radial that identifies the IAF for the arc that published altitude does not apply. Maintain last assigned until you reach that IAF point, then let down to the published altitude. Your MVA may not even be any different at the time in some areas, but check it.

 

[The FNG]

[Something tells me you get into this discussion often with the people you fly with. ]

Something tells me you don't bother landing on the centerline.

[Course alive on a procedure turn on a VOR or ILS/LOC means you can let down.]

Course alive! You gotta be kidding me. You can have course alive well before a LOC 1or LOC 2 message or removal of a LOC flag, and you're going to let down? Tell me where and when you fly so I can keep my family off the flight.

[For NDB's it is within 10 degrees of the final approach course.]

As sketchy as an NDB is and you're comfortable being 10 degrees off. Funny, I've never seen an NDB final approach course published with a "+ or - 10 degree" allowance.

[There are times you might want to fly an ILS a dot high the whole way down, like when you are following a heavy. That is perfectly legit.]

No S**T Sherlock. But usually this is done by maintaining an altitude and flying through the GS, then flying down slightly above in VS mode. Get it, by flying through it you were once centered and thus "established". This is also "technique" not dogma.

[Established means you are within the lateral boundaries, centered or not.]

Lateral boundaries? You just used an example with vertical boundaries. Which one is it?

The P/C Glossary defines established as: To be stable or fixed on a route, route segment, altitude, heading, etc.

It says ON a route. Not BESIDE a route. Routes are not published with a + or - anything. There's one number, period. Are there buffers built in? Of course. But they're for INSTRUMENT ERROR. Not for intentional use, or rather misuse.

Combine + or - 10 degrees plus instrument error and I think I've answered that nagging question you have during post flight of where the tree branches in the gear came from. You can thank me later for clearing that up.

 

[DitchDriver]

I take it this assumes receiving radar vectors. As far as I remember, you can get vectors for any of the listed, but never for a DME arc. See AIM 5-4-3 (b) "... are vectored to the final approach course". The only way to get on an arc is by passing over an intersection, typically IAF on the arc. For that case, see other replies.

There are no DME arc final segments, only initial/intermediate segments are constructed with those.

I can not remember ever being vectored for anything but final course and then told I'm clear for approach. That "maintain (alt) til established, clear for approach" applies only to an intercept on the intermediate segment, if it coincides with final course.

Vectors for anything else, prior to final course will state what vectors are for in the clearance (for traffic, to a fix, etc.) and then it will be "resume normal/own nav".

"Maintain Five thousand until established, you're cleared the ______ approach."

But what if the segment of the published approach in question is defined by a DME ARC?

 

[Deftone45075]

The previous post was the same as what i was thinking. Furthermore, when you are cleared for an approach and told to remain at a specified altitude until "established", this means "final approach coarse" not DME arc. And since a DME arc is NOT part of the Final approach course, you will not be using the fact that you are on the arc to descend.

As Ditchdriver said, if you are recieving vectors, it is to the final approach course, thus bypassing the DME arc all together.

 

[Ty Webb]

Course alive! You gotta be kidding me. You can have course alive well before a LOC 1or LOC 2 message or removal of a LOC flag, and you're going to let down? Tell me where and when you fly so I can keep my family off the flight.[/i]


Sorry, Chief, but he's right . . . . and you're wrong.

"Established" means that you have reliable course indication, within the tolerances of the instrument. There is no "magic" upon "centering" the needle. Either you have a live needle on a functioning instrument tuned to an identified frequency, or you don't- the term "centered" just doesn't come into it, at all.

Even in the B717, one of the most technologically advanced, (full autoland) aircraft out there right now, we get a "LOC Capture" indication long before it ever centers, sometimes before needle movement is even apparent . . . . .

Dogmatic weenies like you loves to focus on the minutaie until they run into the ground, . . . but that is a topic for another string. . . . so you just have yourself a nice one, y'hear?