Do I need the Outer Marker to shoot this approach legally?

[AggieMike88]

Take a look at the ILS18 for Denton. The question du jour is about the LOM.

In November, the beacon went off line and wasn't transmitting. That was fixed. But now the audio panel in the Skylane isn't picking up the signal (no audio, no panel light indicator)

Does hearing the outer marker on approaches designed like this a requirement to shoot a legal approach? Take note it is the FAF.

The aircraft is equipped with a CNX80/480, WAAS and IFR Certified, so I am able to identify the marker position displayed by on the screen. And the localizer/glideslope needles are functioning correctly.


If you have one, provide an FAA citation supporting your answer. I might be doing an IFR checkride in this aircraft and want to be able to properly answer any query with the correct FAA guidance.

 

[jordane93]

http://www.faa.gov/documentLibrary/media/Advisory_Circular/90-108.pdf

http://groundschool.prepware.com/cgi-bin/faraim.pl?subsection_id=25

 

[Clark1961]

The 'ADF REQUIRED' is the clue here for the IAF. Since the GPS can be substituted for the ADF in this case you should be good to go. Note that you shouldn't just watch the LOM position on the screen, use the OBS mode to get to the IAF...or better yet just ask for vectors to a straight in approach.

The marker beacon has no real function in this approach.


Now the TERPS guys will jump on me for being practical rather than following the rules burned into their frontal lobes.

 

[MAKG1]

That does seem odd. Why is ADF required? PINCK can be identified with the Bowie VOR and the localizer, and it's also the MAH. Is it just for the MSA?

Lots of LOMs seem to be going away.

 

[Clark1961]

That does seem odd. Why is ADF required? PINCK can be identified with the Bowie VOR and the localizer, and it's also the MAH. Is it just for the MSA?

Lots of LOMs seem to be going away.

How are you supposed to navigate to PINCK?

 

[AggieMike88]

PINCK can be identified with the Bowie VOR.

There's my "I learned something about aviation today" point. I had been forgetting I could do that. I'll re-add that to my routine.

 

[MAKG1]

How are you supposed to navigate to PINCK?

Well, from Bowie VOR, for one. It's a feeder. And if you're on airways, it appears to be the only viable way with or without ADF.

 

[EdFred]

There's my "I learned something about aviation today" point. I had been forgetting I could do that. I'll re-add that to my routine.

Well, from Bowie VOR, for one. It's a feeder.

But what about getting there from the east side, or north, or southwest, or any place besides the northwest? - assuming you do the full approach.

 

[roncachamp]

Take a look at the ILS18 for Denton. The question du jour is about the LOM.

In November, the beacon went off line and wasn't transmitting. That was fixed. But now the audio panel in the Skylane isn't picking up the signal (no audio, no panel light indicator)

Does hearing the outer marker on approaches designed like this a requirement to shoot a legal approach? Take note it is the FAF.

The aircraft is equipped with a CNX80/480, WAAS and IFR Certified, so I am able to identify the marker position displayed by on the screen. And the localizer/glideslope needles are functioning correctly.


If you have one, provide an FAA citation supporting your answer. I might be doing an IFR checkride in this aircraft and want to be able to properly answer any query with the correct FAA guidance.

No, you do not need to hear the outer marker on approaches designed like this in order to shoot a legal approach.


§91.175 Takeoff and landing under IFR.

(k) ILS components. The basic components of an ILS are the localizer, glide slope, and outer marker, and, when installed for use with Category II or Category III instrument approach procedures, an inner marker. The following means may be used to substitute for the outer marker: Compass locator; precision approach radar (PAR) or airport surveillance radar (ASR); DME, VOR, or nondirectional beacon fixes authorized in the standard instrument approach procedure; or a suitable RNAV system in conjunction with a fix identified in the standard instrument approach procedure. Applicability of, and substitution for, the inner marker for a Category II or III approach is determined by the appropriate 14 CFR part 97 approach procedure, letter of authorization, or operations specifications issued to an operator.

 

[AggieMike88]

No, you do not need to hear the outer marker on approaches designed like this in order to shoot a legal approach.


§91.175 Takeoff and landing under IFR.

(k) ILS components. The basic components of an ILS are the localizer, glide slope, and outer marker, and, when installed for use with Category II or Category III instrument approach procedures, an inner marker. The following means may be used to substitute for the outer marker: Compass locator; precision approach radar (PAR) or airport surveillance radar (ASR); DME, VOR, or nondirectional beacon fixes authorized in the standard instrument approach procedure; or a suitable RNAV system in conjunction with a fix identified in the standard instrument approach procedure. Applicability of, and substitution for, the inner marker for a Category II or III approach is determined by the appropriate 14 CFR part 97 approach procedure, letter of authorization, or operations specifications issued to an operator.

Thanks Steven. So the fact that PINCK overlies DT should have been my big clue for what you cited.

 

[RussR]

That does seem odd. Why is ADF required? PINCK can be identified with the Bowie VOR and the localizer, and it's also the MAH. Is it just for the MSA?

Lots of LOMs seem to be going away.

PINCK is not designated as an intersection made up of the UKW VOR. The radial line does not go through the intersection itself, indicating it's just a feeder route. Likely the course width at 34.9nm from the UKW VOR is too great to meet the requirements of the FAF (but as the IAF before you go outbound on the PT it's good enough).

 

[MAKG1]

PINCK is not designated as an intersection made up of the UKW VOR. The radial line does not go through the intersection itself, indicating it's just a feeder route. Likely the course width at 34.9nm from the UKW VOR is too great to meet the requirements of the FAF (but as the IAF before you go outbound on the PT it's good enough).

Yeah, I'd had some concerns about accuracy with a cross radial.

However, at the final approach fix, the GS should be tracked and the altitude identifies the fix rather precisely if it is.

But I guess there is an issue if you fly it as a localizer only, and don't have a working GS.

 

[roncachamp]

That does seem odd. Why is ADF required? PINCK can be identified with the Bowie VOR and the localizer, and it's also the MAH. Is it just for the MSA?

PINCK is not an intersection, it's an NDB. I didn't do the arithmetic but just by eyeball estimate it doesn't appear to be within fix displacement error limits for a FAF.

 

[AggieMike88]

While we continue to argue the other details, if the examiner says, "Hey, I didn't hear the marker. How did you determine you were at the FAF?" what should my answer be besides, "Well, the GPS went PING! as we crossed it"

 

[mscard88]

But what about getting there from the east side, or north, or southwest, or any place besides the northwest? - assuming you do the full approach.

Navigate to Bowie from any direction, then fly outbound on the 110R, intercept the localizer, fly outbound on the localizer for the procedure turn, then inbound for the approach. Or get a vector from approach control.

 

[mscard88]

While we continue to argue the other details, if the examiner says, "Hey, I didn't hear the marker. How did you determine you were at the FAF?" what should my answer be?

Use Bowie 110 R to identify it.

(you're already on the LOC so there's your sign!)

 

[John Collins]

That does seem odd. Why is ADF required? PINCK can be identified with the Bowie VOR and the localizer, and it's also the MAH. Is it just for the MSA?

Lots of LOMs seem to be going away.

PINCK is not identified by the UKW radial and the localizer. The FAA avoids using the localizer to form an intersection with a VOR radial. When it does, the VOR radial is depicted passing thru the fix with the arrow head on the opposite side of the localizer from the VOR. See KHKY ILS or LOC RWY 24 attached for an example. MIRTY is an intersection formed by the BZM VOR 183 radial and its only use is inbound on the localizer. TAWBA has a feeder route from BZM along the 219 radial, but BZM 219 with the localizer does not define TAWBA.

View attachment 00706IL24 (1).PDF

 

[mscard88]

Yeah, I'd had some concerns about accuracy with a cross radial.
QUOTE]

It's been flight checked and approved by the FAA so you're good to go!

 

[roncachamp]

Well, from Bowie VOR, for one. It's a feeder. And if you're on airways, it appears to be the only viable way with or without ADF.

The Bowie feeder route requires ADF because a feeder cannot dead end at a localizer. A positive fix is required due to the problem of false localizers and the marker beacon does not satisfy the requirement.

 

[roncachamp]

Thanks Steven. So the fact that PINCK overlies DT should have been my big clue for what you cited.

That's what an LOM, a Locator Outer Marker, is; a Compass Locator (an NDB ), and an Outer Marker.

 

[roncachamp]

Navigate to Bowie from any direction, then fly outbound on the 110R, intercept the localizer, fly outbound on the localizer for the procedure turn, then inbound for the approach. Or get a vector from approach control.

How do you know you haven't intercepted a false localizer?

False Localizer Signal

 

[roncachamp]

It's been flight checked and approved by the FAA so you're good to go!

If that was true it would be designated as an intersection in Order JO 7350.9D Location Identifiers. It's not.

 

[mscard88]

I'm researching it!

 

[RussR]

While we continue to argue the other details, if the examiner says, "Hey, I didn't hear the marker. How did you determine you were at the FAF?" what should my answer be besides, "Well, the GPS went PING! as we crossed it"

Are you flying the ILS or the LOC?

If the ILS, then what is the FAF? Hint - it's not PINCK.

The FAF on an ILS is, by definition, when you intersect the glideslope at the published altitude. In many cases, it is collocated with the LOC FAF, which is usually identified by an intersection, an LOM, a DME, etc. But it isn't always. In this case, it's not, the ILS FAF occurs prior to the LOC FAF.

Since the ILS FAF is defined as glideslope intercept, you don't need the LOM, GPS fix, or anything else to identify the FAF. Just your altimeter and the glideslope.

That's the answer.

Now, if you're flying the LOC, of course then you need some way of identifying it. A GPS is a suitable substitute for that just like for all the other cases of GPS substitution you probably have already learned (hopefully!) And, if you don't hear the marker beacon, the GPS IS your only answer, and it's an approved one, so there's no problem.

 

[EdFred]

Navigate to Bowie from any direction, then fly outbound on the 110R, intercept the localizer, fly outbound on the localizer for the procedure turn, then inbound for the approach. Or get a vector from approach control.

Not happening. That's a 70nm detour.

 

[fiveoboy01]

While we continue to argue the other details, if the examiner says, "Hey, I didn't hear the marker. How did you determine you were at the FAF?" what should my answer be besides, "Well, the GPS went PING! as we crossed it"

Well as mentioned by MAKG, if you're on the glideslope, you'll arrive at the FAF at 2,070 feet.

I like these kinds of threads. So many little nuances between approaches and it's helpful to read through to learn.

 

[roncachamp]

Are you flying the ILS or the LOC?

If the ILS, then what is the FAF? Hint - it's not PINCK.

The FAF on an ILS is, by definition, when you intersect the glideslope at the published altitude. In many cases, it is collocated with the LOC FAF, which is usually identified by an intersection, an LOM, a DME, etc. But it isn't always. In this case, it's not, the ILS FAF occurs prior to the LOC FAF.

Since the ILS FAF is defined as glideslope intercept, you don't need the LOM, GPS fix, or anything else to identify the FAF. Just your altimeter and the glideslope.

That's the answer.

Now, if you're flying the LOC, of course then you need some way of identifying it. A GPS is a suitable substitute for that just like for all the other cases of GPS substitution you probably have already learned (hopefully!) And, if you don't hear the marker beacon, the GPS IS your only answer, and it's an approved one, so there's no problem.

How do you ensure you're on the correct GS when flying the ILS?

 

[Cooter]

Are you flying the ILS or the LOC?

The FAF on an ILS is, by definition, when you intersect the glideslope at the published altitude.


N.

Where is that defined? There is an at or above altitude for the appch being discussed. If you are 500' ft high, and intercept GS are you still at the FAF?

 

[roncachamp]

Well as mentioned by MAKG, if you're on the glideslope, you'll arrive at the FAF at 2,070 feet.

Where are you when you reach 2,070 feet if you've intercepted a false glideslope?

 

[fiveoboy01]

That's anyone's guess. That's why I said if you're on the glideslope.

 

[roncachamp]

That's anyone's guess. That's why I said if you're on the glideslope.

It's not a guess for those who identify PINCK and check their altitude at that position.

 

[fiveoboy01]

Right. If you're on a false slope, then at 2070 feet you're going to be inside the FAF and you'll have a much higher than normal descent rate to stay on it.

The solution is to descend where necessary to intercept from below, as there are no false signals below the glideslope.

 

[mscard88]

Still looking but so far I've found an IFR certified GPS w/ current database can be substituted for the LOM, and ADF required for this particular approach because it's the MA hold.

 

[Clark1961]

Well, from Bowie VOR, for one. It's a feeder. And if you're on airways, it appears to be the only viable way with or without ADF.

The VOR gives the direction but doesn't identify the intersection. ADF completes the navigation. My limited experience is the NDB can be such low power that it might not be received until very close. Flying the approach without GPS or radar could really suck. GPS or DME would help.

 

[AggieMike88]

Are you flying the ILS or the LOC?

Originally, I was thinking ILS. But introducing the add on question of LOC is a good point.

 

[RussR]

How do you ensure you're on the correct GS when flying the ILS?

By using the check altitude at the LOM, of course, but you've already answered that in other posts. The other method is to ensure you are at a normal rate of descent for your speed.

Where is that defined? There is an at or above altitude for the appch being discussed. If you are 500' ft high, and intercept GS are you still at the FAF?

Pilot/Controller Glossary:

FINAL APPROACH FIX− The fix from which the
final approach (IFR) to an airport is executed and
which identifies the beginning of the final approach
segment. It is designated on Government charts by
the Maltese Cross symbol for nonprecision
approaches and the lightning bolt symbol for
precision approaches; or when ATC directs a
lower-than-published glideslope/path intercept altitude,
it is the resultant actual point of the
glideslope/path intercept.

Instrument Procedures Handbook, page 4-53

Final Approach Segment
The final approach segment for an approach with vertical
guidance or a precision approach begins where the
glideslope/glidepath intercepts the minimum glideslope/
glidepath intercept altitude shown on the approach
chart. If ATC authorizes a lower intercept altitude, the final
approach segment begins upon glideslope/glidepath
interception at that altitude. For a non-precision approach,
the final approach segment begins either at a designated
FAF, which is depicted as a cross on the profile view, or at
the point where the aircraft is established inbound on the
final approach course.

 

[roncachamp]

By using the check altitude at the LOM, of course, but you've already answered that in other posts.

Which requires more than just your altimeter and the glideslope.

Since the ILS FAF is defined as glideslope intercept, you don't need the LOM, GPS fix, or anything else to identify the FAF. Just your altimeter and the glideslope.

 

[fiveoboy01]

What else would be required?

You'd be a lot more helpful if your posts were written in a way that shares your knowledge, rather than the "I know something you don't know" format.

 

[roncachamp]

What else would be required?

A check of altitude at the LOM requires the ability to determine that the aircraft is at the LOM. That cannot be done with just your altimeter and the glideslope.

You'd be a lot more helpful if your posts were written in a way that shares your knowledge, rather than the "I know something you don't know" format.

I'm sorry. I tend to assume the obvious does not need to be stated. My bad.

 

[PPC1052]

Where is that defined? There is an at or above altitude for the appch being discussed. If you are 500' ft high, and intercept GS are you still at the FAF?

Per the diagram, you are at the FAF for the ILS at the point where you intercept the glideslope at 2700 feet. If you are 500 feet high when you intercept the glideslope, you will intercept the glideslope further out than the FAF for the ILS.