LDA w/ GS missed approach point???

[F/O]

I know, I know....this has been beaten to a bloody pulp here....but with inconclusive results...is it a precision or non-precision, etc.. So rather than debate it I ask you to pull out your Jepps and look at a couple of plates for me.

STL 11-11.....what is the missed app pt?
EGE 11-1...what is the missed app pt?
DCA 11-3...what is the missed app pt?
ROA LDA w/GS Rwy 6 (don't have the index #) ...what is the missed app pt?

Thanks for your input.....

 

[paulsalem]

Look at the top in the briefing strip.

In the location with the minimum altitude, it will denote either MDA or DA.

STL-DA
DCA-MDA MAP is 3.5 DME IASO
ROA-DA

I don't. have EGE Jepps, and looking at the NACO chart, it's very hard to tell. I'm guessing it's a DH, b/c the mins are different for the approach without the GS.

 

[F/O]

Paul

I agree with you in all three cases.

Now, on the STL approach in the lower left below the GS angle it says "MAP at REVRY/D5.1 IRMK" and there is an "M" at REVRY on the profile view. Standard stuff if this approach could be flown with the GS OTS, but note 3 specifically prohibits the procedure if the GS is OTS.

So why is this information there???? Contradictory and confusing at the very least....

 

[avbug]

STL 11-11.....what is the missed app pt?
EGE 11-1...what is the missed app pt?
DCA 11-3...what is the missed app pt?
ROA LDA w/GS Rwy 6 (don't have the index #) ...what is the missed app pt?

What's the mystery here? The approach charts clearly show the missed approach point.

As discussed, The STL 11-11 chart shows the MAP at REVRY at 5.1 DME. The procedure notes also state that the localizer is unusable beyond this point.

Now, on the STL approach in the lower left below the GS angle it says "MAP at REVRY/D5.1 IRMK" and there is an "M" at REVRY on the profile view. Standard stuff if this approach could be flown with the GS OTS, but note 3 specifically prohibits the procedure if the GS is OTS.

What has the glideslope to do with the matter? Nothing. The procedure, as you have noted, cannot be flown without the glideslope. There is one missed approac procedure, the approach cannot be flown without glideslope, and the localizer is unuseable beyond the MAP. I can't see any room for a question or discussion. It's clearly published with no ambiguity.

The EGE 11-1 chart shows a decision altitude of 8330 on the glideslope, from which the missed approach will be executed. Without the glideslope, the missed approach will be executed at CIPKU at the 3.5 DME point on the localizer. Again, very clear.

The KDCA 11-3 chart shows a missed approach at a minimum descent altitude of 1100' with or without the glideslope, to be commenced at 3.5 DME. Again, no ambiguity. With a glideslope, one may ride the glideslope the minimums, and without it one may descend to 1100' immediately after passing MINIE at 6.0 DME, if desired...but the MAP doesn't change.

The KROA 11-2 chart shows a missed approach point at 1580' on the glideslope, or at JOKNI at 1.4 DME without a glideslope available. Again, quite clear.

With this in mind, what is the source of confusion?

Now, on the STL approach in the lower left below the GS angle it says "MAP at REVRY/D5.1 IRMK" and there is an "M" at REVRY on the profile view. Standard stuff if this approach could be flown with the GS OTS...

Standard stuff, period.

So why is this information there???? Contradictory and confusing at the very least....

Are you confused by the entry "MAP at REVRY/D5.1 IRMK?"

As you noted, there is no provision for conducting this approach without the glideslope. Therefore,the usual information that would occupy that line (to be accompanied with times from the previous waypoint to the MAP, for nonprecision purposes where the option is given to conduct the approach without a glideslope. You can look at the STL 11-10 chart as a reference.

Where the option to conduct the approach without a glideslope exists, timing is generally provided to locate the MAP, based on timing inbound from the preceding waypoint. Here it's not an option, and therefore only the MAP is listed, and no times.

Nothing at all contradictory about it. No times are provided and only the MAP details are clearly spelled out, to avoid confusion.

What is it that you find contradictory and confusing?

 

[SpauldingSmails]

... but note 3 specifically prohibits the procedure if the GS is OTS.

So why is this information there???? Contradictory and confusing at the very least....

REVRY at 5.1 dme is depicted so that you know when you can begin the missed approach segment... i.e. turn off the LOC. If you were to blunder off-slope on the approach, or say the glidepath were to fail while the approach in progress you'd have no way of identifying the MAP by using DA. That's all... no drama.

 

[paulsalem]

Paul

I agree with you in all three cases.

Now, on the STL approach in the lower left below the GS angle it says "MAP at REVRY/D5.1 IRMK" and there is an "M" at REVRY on the profile view. Standard stuff if this approach could be flown with the GS OTS, but note 3 specifically prohibits the procedure if the GS is OTS.

So why is this information there???? Contradictory and confusing at the very least....

I have no idea. (See below of some reasoning)

REVRY at 5.1 dme is depicted so that you know when you can begin the missed approach segment... i.e. turn off the LOC. If you were to blunder off-slope on the approach, or say the glidepath were to fail while the approach in progress you'd have no way of identifying the MAP by using DA. That's all... no drama.

The ILS PRMs and CAT II & III ILS at STL are NA w/o the glide slope. However, there is no published MAP like the LDA w/ glide slope.

Bug,

Can you re-word your explanation this in your first post. I don't quite get it.

 

[SpauldingSmails]

Excerpts from the AIM to elaborate a little more on my reasoning.

AIM 5-4-21 Missed Approach. Para. B.

Reasonable buffers are provided for normal maneuvers. However, no consideration is given to an abnormally early turn. Therefore, when an early missed approach is executed, pilots should, unless otherwise cleared by ATC, fly the IAP as specified on the approach plate to the missed approach point at or above the MDA or DH before executing a turning maneuver.

In the case of the of LDA/DME approach, its good sense for them to mark the location inspite of the fact that a DA is used because its an odd location, and the LOC becomes unusable beyond a point.


With regard to the PRM or Cat II/III approaches I suppose the assumption is made that either you will be able to approximate the location of the runway threshold based on the LOC dme information, or as radar is required (in addition to dme) that an alternate missed instruction to turn would be issued prior to reaching the approximate MAP.


Also from the AIM...


Chart Terminology - Decision Altitude (DA)
The aircraft is expected to follow the missed instructions while continuing along the published final approach course to at least the published runway threshold waypoint or MAP (if not at the threshold) before executing any turns.


Again, theres the assumption you'd be able to approximate the location of the runway threshold based on DME information if you were to royally hose up the approach. Or that you would likely be issued alternate instructions as it is a PRM monitor approach. Not shown on the PRM but rather the "regular" CAT III ILS RWY 11 are the MM and IM depicted, which would provide you with the neccesary information as to when to turn for the missed approach.

 

[avbug]

Can you re-word your explanation this in your first post. I don't quite get it.

I do not understand your sentence.

The original poster inquired regarding identifying the missed approach point. It is unambiguous and obvious, without room for discussion. Where exactly does the confusion lie?

 

[paulsalem]

I do not understand your sentence.

Heh. Yea I can understand that.

The original poster inquired regarding identifying the missed approach point. It is unambiguous and obvious, without room for discussion. Where exactly does the confusion lie?

Nevermind, there is no room for discussion.

The interweb is full.

 

[Grey Ghost]

who cares?