Maintain [altitude] until established

big_news_1

Well-Known Member
I have heard each of the following phrases when accepting vectors for the ILS 30C @ IWA:

"Turn left heading 330, maintain 3500 until established"

-and-

"Turn left heading 330, maintain 3500 until established on the localizer"


Is there any distinction between the two? Is "on the localizer" implied in the first phrase or could ATC be asking you to intercept glideslope at an altitude higher than the published altitude (3300 in this case)?
 
I have heard each of the following phrases when accepting vectors for the ILS 30C @ IWA:

"Turn left heading 330, maintain 3500 until established"

-and-

"Turn left heading 330, maintain 3500 until established on the localizer"


Is there any distinction between the two? Is "on the localizer" implied in the first phrase or could ATC be asking you to intercept glideslope at an altitude higher than the published altitude (3300 in this case)?


No difference. One is just a couple more words of verbiage than the other. Their telling you not to descend to glide slope intercept until established on the LOC (case break). And, if you're outside useable range for the LOC (18 miles) being vectored, ATC will tell you to:

"Intercept the IWA R-122 inbound and maintain 3500, until established on the LOC. Cleared ILS 30C...."
 
Is "on the localizer" implied in the first phrase

What is really meant in both instances is "until established on a published segment of the approach", as specified in 14 CFR 91.175(i). In some instances, you may intercept the localizer outside the published portion of the approach and you must maintain the assigned altitude until you get on a black line.

Note: The published approach does not necessarily coincide with the physical limits of the localizer signal...and probably doesn't.
 
Thanks for the clarification, guys.

What is the verbiage used if ATC desires you to intercept the glideslope at a higher-than-published altitude? It seems I have been perpetuating a misconception, and I want to get my facts straight.
 
Thanks for the clarification, guys.

What is the verbiage used if ATC desires you to intercept the glideslope at a higher-than-published altitude? It seems I have been perpetuating a misconception, and I want to get my facts straight.

Once you get "fly heading 330 to intercept, cleared for the ILS rwy 30C", that clears you to fly the IAP as published and not have to be of the vectored heading. You can descend to glideslope intercept and track from there. I've never heard anything specific about ATC wanting you to intercept at a higher altitude....you yourself can if you like, just crosscheck the glideslope check altitude at the appropriate point on the IAP.
 
Interesting... I've never actually seen the HI-ILS 30C procedure before. The normal ILS 30C doesn't have a "check" altitude, per se; it is simply the glideslope intercept altitude, which does coincide with SNOWL at 6.4 DME. Here's the procedure:

http://204.108.4.16/d-tpp/0905/00074IL30C.PDF

But the HI-ILS illustrates the concept, which I understand. I usually have my students do that at SNOWL, but didn't know it had a name.

Thank you for the help guys. For some reason I had the misconception that the instruction "Maintain until established" indicated the glideslope intercept altitude, and that you shouldn't descend to the published altitude unless specifically instructed to "Maintain until established on the localizer".
 
Interesting... I've never actually seen the HI-ILS 30C procedure before. The normal ILS 30C doesn't have a "check" altitude, per se; it is simply the glideslope intercept altitude, which does coincide with SNOWL at 6.4 DME. Here's the procedure:

http://204.108.4.16/d-tpp/0905/00074IL30C.PDF

But the HI-ILS illustrates the concept, which I understand. I usually have my students do that at SNOWL, but didn't know it had a name.

Thank you for the help guys. For some reason I had the misconception that the instruction "Maintain until established" indicated the glideslope intercept altitude, and that you shouldn't descend to the published altitude unless specifically instructed to "Maintain until established on the localizer".

I posted the HI-ILS in order to do just that, illustrate it for you. Normally, the check altitude (which is always published) coincides with the glideslope intercept altitude, but not always. On the (low) ILS 30 at KDMA, the glideslope intercept altitude is a "hard" 4500, but the glideslope check altitude is 4490.

See what we north Tucson people with nothing to do, do with our time? :D
 
Lol, well once again thanks for the assist. I'm a little embarrassed that I've been interpreting the instruction incorrectly all this time, but I'm glad I can rectify the error without any damage done!

Always learning something, I guess :eek:
 
Interesting... I've never actually seen the HI-ILS 30C procedure before. The normal ILS 30C doesn't have a "check" altitude, per se;]
Actually, it does.

The 3300 above the Maltese cross (not the underlined altitude) is a reference to how high you should be when you are directly over the fix and exactly on glideslope. It's a check altitude as Mike described.

In the 30C procure you post, it happens to be the same as the minimum altitude for glideslope intercept. But it doesn't have to be. Compare KAPA ILS 35R in Denver. If you look at the NACO Chart Users Guide, you'll see it referred to as the "Glide Slope Altitude at Outer Marker/FAF"
What is the verbiage used if ATC desires you to intercept the glideslope at a higher-than-published altitude?
Exactly the same: "Maintain XXXX until intercepting the localizer."
 
Exactly the same: "Maintain XXXX until intercepting the localizer."

I think the question was more about intercepting the glideslope at a higher than normal altitude vs. intercepting the localizer at a higher than normal altitude. The verbiage you posted would still allow the pilot to descend to the normal glideslope intercept altitude upon reaching the localizer.

The question that big_news_1 was asking (as I understand it) is "If ATC wanted you to be at an altitude above the altitude printed on the approach plate, so that you intercept the glideslope at an altitude higher than that printed on the plate, how would they ask?"

For the answer, I don't know if there is any particular verbiage they would use, because this isn't a common request. They could just say, "maintain XXXX altitude until glideslope intercept" or "Maintain XXX altitude, and intercept glideslope at XXX altitude, cleared approach" I suppose.

But I think the real answer is that more than likely they wouldn't ask you to do that. Instead, they might ask you to maintain XXX altitude until a particular point on the approach. Even that, however, would be unusual but I suppose it could happen. I think the most likely thing you would hear would be something like, "Maintain XXX until XXXXX point, cleared ILS 24 yada, yada, yada..." or maybe "Maintain XXX until 2 miles prior to XXXXX point, cleared ILS 05 yada, yada, yada" or even "maintain XXX altitude until the Final Approach Fix, cleared...."
 
But I think the real answer is that more than likely they wouldn't ask you to do that.
I think you are right the I mis-interpreted the question.

The real answer is that if they asked you to maintain a higher altitude, it would be because something about the context made it necessary. And then the language they would use would reflect what they needed you to do. You gave some good examples.

Another example:

There was a situation here last year in which there was traffic being vectored from two sides of the localizer. One was also further out than the other. The idea was to bring the faster one in and clear it and maintain IFR separation with both distance and altitude.

The faster one was instructed (these aren't exact) to "turn left heading 020, maintain 8000 (normal) until established, cleared for the ILS..."

The slower one, which was already at 9000' was instructed to "turn right heading 330 join the localizer."
 
When flying into MEM I am usually told to "Cross REISE at 3,000, maintain 170 until RONEE Cleared ILS 18L" which is minimums however they could ask you to cross REISE at 4,000.
 
When flying into MEM I am usually told to "Cross REISE at 3,000, maintain 170 until RONEE Cleared ILS 18L" which is minimums however they could ask you to cross REISE at 4,000.

In your case, it would be improper for them to say "maintain 3000 until established on the localizer" because you would get established on the LOC well before REISE and there is no published segment prior to REISE. ATC can only use the phraseologoy "until established on the localizer" if you will truly be established on a segment of the approach once you do intercept the localizer, based on your anticipated course. They are sloppy about this and many may not understand the difference.
 
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