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ILS altitudes

RJLoser

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Once cleared for the approach and on glideslope, if GS is maintained are there approaches out there where the glideslope will take you under published minimum crossing/safe altitudes on the approach plate?

If yes, once cleared for the approach you must deviate above GS in order to maintain minimum published altitude?

Also, are the ALT deviations so large as to be violated?
 

satpak77

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Once cleared for the approach and on glideslope, if GS is maintained are there approaches out there where the glideslope will take you under published minimum crossing/safe altitudes on the approach plate?

If yes, once cleared for the approach you must deviate above GS in order to maintain minimum published altitude?

Also, are the ALT deviations so large as to be violated?

what are you asking, I am confused. If cleared for ILS, and GS is operational, take it to mins if need be. If GS is out you have to abide by the altitudes on the chart.
 

RJLoser

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No, I was talking about if cleared for the approach a few thousand feet above / and outside the FAF as often the case in larger airports. The app plate has fixes with published altitudes. I was asking if specific approaches have glideslopes that will have you hit those fixes at an altitude different than those on the plate (lower). LAX and SLC I believe are 2 that have this issue.

Enough altutude to cause a altitude deviation violation?
 

tomgoodman

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Taking no chances

No, I was talking about if cleared for the approach a few thousand feet above / and outside the FAF as often the case in larger airports. The app plate has fixes with published altitudes. I was asking if specific approaches have glideslopes that will have you hit those fixes at an altitude different than those on the plate (lower). LAX and SLC I believe are 2 that have this issue.

Enough altutude to cause a altitude deviation violation?

I recall the one you are talking about at LAX, and always thought I had to comply with the altitudes outside "Fuelr". The localizer is certified for an extra-long distance, but maybe the glide slope is not. Never got around to asking ATC for a definitive answer.
 

Mach 80

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It may have changed, but last I heard the GS was only flight checked for accuracy from the final approach fix on in. There were some glide slopes that if followed from a distance out from the FAF would take you slightly below the next published crossing altitude on the ILS and also would take you below class B. Somebody told me the FAA corrected these locations but I'm not certain. I often follow the GS way outside the FAF but am ready to intervene if it takes me below a Class B or published fix.
 

Amish RakeFight

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The step downs obviously take precedence outside of the FAF. Fly the GS if you pick it up, but adhere to the published step down altitudes if the GS will take you below it, prior to the GSIA.
 

2EASYPilot

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The step downs obviously take precedence outside of the FAF. Fly the GS if you pick it up, but adhere to the published step down altitudes if the GS will take you below it, prior to the GSIA.

This happens at KMDW a lot. They will have you at 4000 and clear you for the ILS 31C to cross Gleam at 4000. In this case intercepting the GS will give you the 4000 @ Gleam.

http://www.naco.faa.gov/d-tpp/0813/00081ILD31C.PDF
 

Stifler's Mom

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CVG 18C ILS

The GS takes you below the minimums at ANTRI (6000') and DULEY (5000').
 

great cornholio

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ORD has a few that you have to do this. They even put out a big letter about it (not sure if it was just my company that did the letter or if they sent it to everyone). Anyways they said that the WAIVE at 5000 protects MDW traffic and must be adhered too and the GS will put you below 5000 at WAIVE (might have a new name now with the new runway open).

As it was said above you should comply with the step downs prior to the FAF and if you can meet them on GS then fly the GS. If not then you have to do the step down. Laziness pretty much always sets in and most of the time people just fly the GS without paying attention to the step downs...usually its ok and will not bust anything, but there are a few cases were it will bust a step down.
 

Fox-Tree

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Doesn't the depiction of the "Fan" on the approach plate have something to do with this? The civet arrival and approach to 25L at LAX have crossing restrictions that will be violated if you follow the GS too soon. The "fan" is only out to the marker and if you use that (as to when to follow GS, you're safe).
 

Booker

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Doesn't the depiction of the "Fan" on the approach plate have something to do with this? The civet arrival and approach to 25L at LAX have crossing restrictions that will be violated if you follow the GS too soon. The "fan" is only out to the marker and if you use that (as to when to follow GS, you're safe).

Without looking at chart legends, I'd say that's correct for Jepp profile views. The fan extends to the GSIA and is analogous to the lightning bolt on government charts. However, the length of the fan in the plan view is typically not coincident with its length in the profile view and typically extends beyond the location of GS intercept.
 
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