Maintain (altitude) until established

[meritflyer]

I need a little help from my fellow CFI friends and controllers ..

When we're shooting an ILS and ATC says "turn right heading 250, maintain 4000' until established, cleared for the RWY X ILS"

I always thought it they put us on an intercept altitude (4000' in my example)

Today, I was told that we should maintain the 4000' until established on the LOC course, then descend to our intercept altitude shown on our profile view for GS intercept.

Whats the correct way?

[averyrm]

Either is fine as long as the intercept altitude published is a minimum altitude.

Going down after establishing is faster, depending on how you shoot the approach.

[meritflyer]

I guess the question should be, are the altitudes assigned in the "maintain 4000' until established" clearances, GS intercept altitudes?

[averyrm]

They can be, if you want to stay up there. Once you're established, you have the option of decending to 3000, or whatever's published, or staying at the altitude they assigned, intercepting the glideslope, and following it down.

Assuming of course, there are no maximum or manditory altitudes on the approach.

[Doug Taylor]

I'm not an air traffic controller, but I usaully maintain last assigned on an ILS.

[averyrm]

Originally Posted by Doug Taylor

I'm not an air traffic controller, but I usaully maintain last assigned on an ILS.

I think that's a lot easier, but the way we fly - it's not as fast.

[meritflyer]

Originally Posted by averyrm

They can be, if you want to stay up there. Once you're established, you have the option of decending to 3000, or whatever's published, or staying at the altitude they assigned, intercepting the glideslope, and following it down.

What about not intercepting the GS from above the intercept altitude? Thats definately a no no and if published in the IFH as it could lead to erroneous GS indications (false GS).

So, the altitudes they assign to you maintain until established must be GS intercept altitudes.

Controllers care to chime in?

[averyrm]

Well, if you're intercepting the slope from below then you won't have any problem. The false glideslopes are higher (6 and 12 deg?). Plus the altitudes are still published as a minimum, so you can be higher than that. Just doublecheck crossing the marker (or dme) that your altitude matches what's listed.

[meritflyer]

9-12 degrees is where the courses will occur. Does that mean that instead of flying the course at 3 degrees, at 9 and 12 degrees ABOVE the glidepath is where the false courses will occur?

I am still a little if'y whether the altitudes that ATC give you are actual tested GS intercept altitudes.

[wheelsup]

Originally Posted by meritflyer

Whats the correct way?

I think it depends on where you are on the approach and the approach design.

If there is another fix between the FAF/GS intercept with a minimum altitude I'll descend down to that intermediate altitude because I don't want to bust the minimum altitude at that fix. Capturing the GS won't assure that you will make that fixes altitude requirement.

We had a discussion on here some time ago I remember - I had a controller actually get upset at us for not descending down immediately to the next step down on the fix. Kinda funny. It was always the same controller too.

[CFIse]

Originally Posted by meritflyer

I guess the question should be, are the altitudes assigned in the "maintain 4000' until established" clearances, GS intercept altitudes?

Most of the time yes - but I don't think it has to be, or at least if it is a rule some controllers don't follow it.

Cleveland - approaching over the city they will give you a heading and an altitude assignment with an approach clearance that will have you join the localizer above the glideslope. I have had that in IMC.

So the moral of the story - pay attention - because you may sit there fat dumb and happy, like I did, until the captain says "should we start down" in that tone of voice that means "start down dumbass".

I've never had it happen anywhere else, although I hear the "slam dunk" is a West Coast thing and I don't fly much out there.

[meritflyer]

I guess this question can be summed up to this:

When told to maintain (altitude) until established, is that the LOC or the GS?

Will ATC say "maintain (altitude) until established on the localizer, cleared for RWY X approach".

I shot the ILS into KCRQ and was told the maintain (altitude), cleared for the ILS. No mention of LOC.

Is there any variance specified by ATC whether you're supposed to stay at altitude until LOC course guidance is rec'd then descend to your intercept altitude or stay at your last assigned until GS intercept?

[pilotnate23]

You must maintain the altitude assigned until you have course guidance for the final approach course. The reason is most often a TERPS/MVA issue. For example, in the facility I work in, the MVA around the airport is 5000, but the GS intercept for its ILS is 4700. If you went to 4700 before being near the final approach course, we'd get an MSAW (minimum safe altitude warning) alert.

- Nate

[CFIse]

Originally Posted by meritflyer

I guess this question can be summed up to this:

When told to maintain (altitude) until established, is that the LOC or the GS?

It's the LOC - which is to say if you are on GS but full scale on the LOC you are not established.

Will ATC say "maintain (altitude) until established on the localizer, cleared for RWY X approach".

Assuming it's an ILS approach that's unlikely phraseology, although probably not unheard of. You'd probably hear "maintain (altitude) until established, cleared for the ILS approach runway (runway)". If it's a localizer only approach then it's OK phraseology, but still not by the book correct. Established on the localizer is typically used to mean intercept and follow the localizer but do not descend. Typically that WON'T come with an "maintain until" limitation. It might come with a "descend and maintain".

I shot the ILS into KCRQ and was told the maintain (altitude), cleared for the ILS. No mention of LOC.

See I'm a genius - that's what you would expect, they expect you to maintain the assigned altitude until you are on a published portion of the approach and then fly the approach with altitudes as published.

Is there any variance specified by ATC whether you're supposed to stay at altitude until LOC course guidance is rec'd then descend to your intercept altitude or stay at your last assigned until GS intercept?

I've seen this discussion a number of times - the general response is that as long as there are no MAXIMUM altitudes published on the approach then you can do whatever you want. Stay up or go down. Personally I stay up and intercept the GS and follow it down. I think you mentioned earlier that slows you down because of the procedures at your employer. I have no idea what would happen if you did it on a PC at our company, but in the "real world" as long as we're configured and stable by 1,000ft AGL you can pretty much do what you want as long as neither crew members complains. Unless told to do otherwise I rarely slow under 200K before the FAF on an ILS.

[casey]

Originally Posted by meritflyer

What about not intercepting the GS from above the intercept altitude? Thats definately a no no and if published in the IFH as it could lead to erroneous GS indications (false GS).

i think you have "intecepting the GS from above" and "intercepting at a higher than normal altitude" confused. Like said by someone else earlier if you intercept from below, at any altitude approach would be giving you, you will be safe. The danger comes when you are higher than the GS (way higher) and diving for the GS in territory that you may snag a false indication.

[meritflyer]

Thanks for the responses. I guess my biggest thought was when they say - turn left 270, maintain 3000 until established, cleared for the ILS - is the 3000 an acutal intercept altitude. But I guess it depends. As for the word "established", I wasnt sure if that meant on the GS or just on an approach segment.

[EatSleepFly]

Originally Posted by CFIse

I think you mentioned earlier that slows you down because of the procedures at your employer. I have no idea what would happen if you did it on a PC at our company, but in the "real world" as long as we're configured and stable by 1,000ft AGL you can pretty much do what you want as long as neither crew members complains. Unless told to do otherwise I rarely slow under 200K before the FAF on an ILS.

I think it's just a techinque thing, unless of course there are maximum or mandatory altitudes to be complied with. Especially on single-engine ILS's, I'd rather intercept at the initial assigned altitude, rather than keep making large power changes to descend and level off at each stepdown. I had a low-time training captain tell me it was bad form once, but I fail to see how something that's perfectly legal, and makes things easier (especially in the single-pilot/emergency environment), is "bad form."

[casey]

Originally Posted by meritflyer

Thanks for the responses. I guess my biggest thought was when they say - turn left 270, maintain 3000 until established, cleared for the ILS - is the 3000 an acutal intercept altitude. But I guess it depends. As for the word "established", I wasnt sure if that meant on the GS or just on an approach segment.

depends on your chart. If they say maintain 3000 till established, then as soon as you are established (loc alive, positive course guidance on final) then you are free to descend via the published approach. If the GS intercept is for example 2000 or above, then you can stay at 3, descend to 2, intercept at either altitude is fine, just a matter of technique.

Once established and cleared for the approach you have to comply with the published altitudes, but most are "at or above". As long as there are no "at or below" or "mandatory" altitudes, you should be able to just ride along at 3 and wait for the GS there.

[meritflyer]

I was always under the impression that intercepting the GS at altitudes higher than the published intercept altitude may lead to errors.

[EatSleepFly]

It should never be intercepted from above. That can result in a false glideslope (although I've tried many times on visual approaches, and have never been able to get one).

What I was talking about would be intercepting it further out, and thus higher up (but still from below), than the GS intercept altitude shown on the chart- eliminating the need to descend and level off at every step down.

This only works if:

1.) You're cleared for the approach,
2.) There aren't any maximum or mandatory altitudes on any of the stepdowns, and
3.) You are intercepting the GS from below.

[mikecweb]

The clearence you are getting is the Minimum vectoring altitude from the controller. "Maintiain 3,000 until established on the localizer cleared ILS 30L".
So after you get positive indication on your localizer, you can descend to whatever it says on your plate.
I've always flown by the school of thought that you go as low as you can legally at that particular time. Whats the point of staying at 3,000 when you can goto 2,400 or the such?

[zmiller4]

Originally Posted by EatSleepFly

It should never be intercepted from above. That can result in a false glideslope (although I've tried many times on visual approaches, and have never been able to get one).

I agree--the altitude you intercept it at is [almost] irrelevant, and that it's intercepting from above that can get you. We got a false glideslope on a visual at Bakersfield on Friday--it was pretty impressive how accurate it looked for a little while (disclaimer: we were visual and way far out).

This only works if:

1.) You're cleared for the approach,
2.) There aren't any maximum or mandatory altitudes on any of the stepdowns, and
3.) You are intercepting the GS from below

I agree with this as well--I always try to get on the glideslope as far out as is logical to get things stabilized, but there's approaches out there with multiple stepdowns where following the glideslope can put you below minimum altitudes at stepdowns. Some of the ILS's into LAX can do this to you.

[CFIse]

Originally Posted by mikecweb

Whats the point of staying at 3,000 when you can goto 2,400 or the such?

This is just a technique thing - we've seen a number of descriptions of the point of staying at 3,000 until intercept - smoother, not so much descent and level off etc.

What's the point of descending to 2,400 when you can?

Seriously - you might change my flying technique.

[mikecweb]

Well first of all your intercepting the GS at the specified altitude as depicted on the plate and not making up your own plate. Secondly remember what the goal of an instrument approach is.. get under the weather so you can see the airport. If your comfortable doing it the other way I'm sure it'll all be good but this is just the way I've been trained and how I interpret the correct way of shooting an instrument approach. I just don't wanna hear the arguement that being higher is being safer.

[tgrayson]

Originally Posted by meritflyer

But I guess it depends. As for the word "established", I wasnt sure if that meant on the GS or just on an approach segment.

The altitude assigned is one that keeps you safe until established on a published segment of an approach. After that, published altitudes apply. See 91.175. A published segment is a bold, black line.

The localizer itself is not a published segment, because it exends much farther out than what has been surveyed by the approach designers. Only the part that overlies a bold, black line is a published segment. Many times controllers will vector you to intercept the localizer beyond the fix where the intermediate course begins; when you intercept the localizer, you are not yet on a published segment, and you must wait until you reach a fix that marks the beginning of the segment. ATC is not supposed to use the phraseology "until established" in this scenario, unless the vector will actually put you on a published segment. But they do. Instead, they're supposed to give you a crossing restriction, "maintain 3,000 until crossing X, cleared ILS Rwy YY." At your option, you can remain at the assigned altitude or descend to a published altitude, absent any maximum or mandatory altitudes on the approach. These are rare.

I teach descending to the published altitudes, mainly to get the student in the habit of paying attention to such things. On a non-precision approach, it could make a difference between getting in or not. Real world, however, many pilots will remain at the assigned altitude and just intercept the GS at the higher altitude. Where the cloud layers are could affect this decision, as would the presence of icing.

Be aware, though, the GS is not primary for altitude guidance until the FAF, so if there are any step down fixes prior to that point, you're still bound by them, regardless of where the GS is taking you. This is a factor for some approaches out west, from what I understand.