FAF Altitude?

Don Jones said:
Well my II is almost as wet as Chips, but seems to me the only reason as stated earlier for the FAF symbol is for timing for the missed, and after completion of the procedure turn at or above 2400, once established inbound on the radial you can desend down to 1580 ft.
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Disagree... If for no other reason than it's ambiguous (is the mistake the lack of a level line, or the lack of an altitude?), so for safety's sake you stay at or above 2400 until the FAF regardless of what you think it's supposed to be.

But, looking at the Jepp chart, we can see that it's meant to be 2400 at the FAF. And yes, Jepp and NACO get their data from the same place, I believe it's all just a database from which the plates are generated. I think NACO screwed up here, I'd be interested to see what Ron finds out.
 
I don't think there's any doubt that the NACO chart as printed allows descent to 1580 as soon as you're established on the 304 radial out of the PT inbound to the VOR (which just doesn't seem appropriate to me). Futher, it's clear that the Jepp chart includes a 2400 restriction until passing the VOR/FAF inbound to the airport. Thus, it's clear to me that either the Jepp chart or the NACO chart is incorrect -- and when that happens, "I feel a great disturbance in the Force." We'll see what AFS-400 says.
 
Ron Levy said:
I don't think there's any doubt that the NACO chart as printed allows descent to 1580 as soon as you're established on the 304 radial out of the PT inbound to the VOR (which just doesn't seem appropriate to me).
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I don't agree that there is "No doubt", I have plenty of doubts about that approach. With that Maltese FAF cross charted there is an altitude tag missing at that waypoint, be it 2400 or something less. I do not think a straight decent to 1580 is what is charted there. If that were the case the FAF Maltese cross should not be there as depicted.
 
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Dave Siciliano said:
The descending line from 2400 to the VORTAC is incorrect; it should be level (as the Jepp chart shows).
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Here's another way to look at it:

The descending line from 2400 to the VORTAC FAF would be incorrect if the altitude depicted for the PT was 2400 MANDATED (line above and below). However, it's depicted that the PT should be flown ABOVE 2400 (2400). I could fly the PT at 3600 or 5400 or 2750, and be "fully legal" on this approach. I don't have to get down to 2400 (OR HIGHER, just not lower than 2400) until passing the VOR inbound, at the FAF.

Therefore, the slanting/descending line from PT back to the VOR is okay, in my book.
 
TangoWhiskey said:
Here's another way to look at it:

The descending line from 2400 to the VORTAC FAF would be incorrect if the altitude depicted for the PT was 2400 MANDATED (line above and below). However, it's depicted that the PT should be flown ABOVE 2400 (2400). I could fly the PT at 3600 or 5400 or 2750, and be "fully legal" on this approach. I don't have to get down to 2400 (OR HIGHER, just not lower than 2400) until passing the VOR inbound, at the FAF.

Therefore, the slanting/descending line from PT back to the VOR is okay, in my book.
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I believe the charts show minimum altitudes: therefore 2400 procedure turn inbound, 2400 at FAF is what the line should show--as depicted on the Jepp chart. There are many cases like this where one can be at or above--the lines depict minimums.

Best,

Dave
 
I have been looking into this some more. According to the Instrument Procedures Manual the vor procedure has a minimum of 300 feet obstacle clearance in the final approach area. I see nothing terrain wise, towers, etc which violate that rule at 1580 feet. Being able to identify ADEBE lets you desend to 1220 which still does not violate the 300 feet rule inside ADEBE. Without any obstructions that violate that rule I am beginning to think NACO charted it the way they intended. Here is the quote from the manual.​

"This type of VOR approach also includes a minimum of 300 feet of obstacle
clearance in the final approach area. The final approach area criteria include a
2 NM wide primary area at the facility that expands to 6 NM wide at a distance
of 10 NM from the facility."​
 
Dave Siciliano said:
I believe the charts show minimum altitudes: therefore 2400 procedure turn inbound, 2400 at FAF is what the line should show--as depicted on the Jepp chart. There are many cases like this where one can be at or above--the lines depict minimums.

Best,

Dave
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Exactly, Dave... with the line under it, it's a minimum, not mandatory altitude. Therefore, I could still be decending to 2400 once inbound from the PT... I don't have to be "at 2400" for the PT.

I think we're saying the same thing... but why depict the same "mimimum" altitude twice? This one altitude applies to the entire intermediate segment.
 
TangoWhiskey said:
I think we're saying the same thing... but why depict the same "mimimum" altitude twice? This one altitude applies to the entire intermediate segment.
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Not the way it's printed, which is the point. As printed on the NACO chart, the 2400 foot restriction ends when you intercept the 304 radial back inbound to SVM. However, as printed on the corresponding Jepp chart, the 2400 restriction applies all the way back to SVM. That's an unacceptable contradiction.
 
Ron Levy said:
Not the way it's printed, which is the point. As printed on the NACO chart, the 2400 foot restriction ends when you intercept the 304 radial back inbound to SVM. However, as printed on the corresponding Jepp chart, the 2400 restriction applies all the way back to SVM. That's an unacceptable contradiction.
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I definately agree with that!
 
Ron Levy said:
Not the way it's printed, which is the point. As printed on the NACO chart, the 2400 foot restriction ends when you intercept the 304 radial back inbound to SVM. However, as printed on the corresponding Jepp chart, the 2400 restriction applies all the way back to SVM. That's an unacceptable contradiction.
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I can see where you're going with that... it can certainly be depicted clearer. If that 2400 was drawn once, at (just outside) the FAF, there'd be no question.

However, since you cannot begin your descent to the MDA until after passing the FAF, I still say the 2400 applies all the way to the FAF, to the entire segment, as no other minimum altitude is depicted at the FAF.

I'm very interested to see what AFS says in response to your query--how long has experience told you it will take for a reply?
 
Since you are supposed to brief your altitude at the FAF, as all good instrument training materials and the FAA state, if you were to start your descent inbound from the the procedure turn what altitude would you brief as you crossed the FAF?
 
Ron Levy said:
Can you point to a regulation, TERPS standard, or even an AIM section which says that? I don't know of one.
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I have been looking for one all morning, I have even been looking at ICAO documents. But alas have not found one, knowing if I did it would be the answer and would really remove doubt about what is being depicted on this chart.

I did find one interesting entry in the AIM though. It is not the holy grail of what we want, but I find it interesting nonetheless.

On section 5.4.5 paragraph 6.(a)(1)

6. Chart Symbology changed slightly to include:
(a) Descent Profile. The published descent profile and a graphical depiction of the vertical path to the runway will be shown. Graphical depiction of the RNAV vertical guidance will differ from the traditional depiction of an ILS glide slope (feather) through the use of a shorter vertical track beginning at the decision altitude.
(1) It is FAA policy to design IAPs with minimum altitudes established at fixes/waypoints to achieve optimum stabilized (constant rate) descents within each procedure segment. This design can enhance the safety of the operations and contribute toward reduction in the occurrence of controlled flight into terrain (CFIT) accidents. Additionally, the National Transportation Safety Board (NTSB) recently emphasized that pilots could benefit from publication of the appropriate IAP descent angle for a stabilized descent on final approach. The RNAV IAP format includes the descent angle to the hundredth of a degree; e.g., 3.00 degrees. The angle will be provided in the graphically depicted descent profile.
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Clearly that guideline is not being followed here.
 
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Some more assistance on this topic
FAA Inst Procedure Manuaal Chapter 5 said:
FINAL APPROACH FIX ALTITUDE
Another important altitude that should be briefed
during an IAP briefing is the FAF altitude, designated
by the cross on a nonprecision approach, and the lightning
bolt symbol designating the glide slope intercept
altitude on a precision approach. Adherence to and
crosscheck of this altitude can have a direct effect on
the success of an approach.

Proper airspeed, altitude, and configuration, when
crossing the FAF of a nonprecision approach, are
extremely important no matter what type of aircraft is
being flown. The stabilized approach concept, implemented
by the FAA within the SOPs of each air carrier,
suggests that crossing the FAF at the published altitude
is often a critical component of a successful nonprecision
approach, especially in a large turbojet
aircraft.

The glide slope intercept altitude of a precision
approach should also be included in the IAP briefing.
Awareness of this altitude when intercepting the glide
slope can ensure the flight crew that a “false glide
slope” or other erroneous indication is not inadvertently
followed. Many air carriers include a standard
callout when the aircraft passes over the FAF of the
nonprecision approach underlying the ILS. The pilot
monitoring (PM) states the name of the fix and the
charted glide slope altitude, thus allowing both pilots to
crosscheck their respective altimeters and verify the
correct indications.
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Again this just raises the question of what altitude you should be at when you cross the FAF. IMHO that indicates that there should be some sort of chart marking at the FAF stating the altitude even if that altitude is still 2400
 
Ron Levy said:
Can you point to a regulation, TERPS standard, or even an AIM section which says that? I don't know of one.
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That's a great question... I love ones that make you think!

I did a cursory look and didn't find one, I'll look more later. Are you suggesting you can start your descent to the MDA prior to the FAF? The FAF often has a crossing altitude listed. If it doesn't, then would not the lowest altitude depicted for the intermediate segment rule? The FINAL APPROACH segment begins at the FAF... so the MDA isn't applicable til after that, common sense tells us.

I'm intrigued to know where you're leading me with this... I have a feeling I'm about to learn something new. :)
 
smigaldi said:
Some more assistance on this topic
Again this just raises the question of what altitude you should be at when you cross the FAF. IMHO that indicates that there should be some sort of chart marking at the FAF stating the altitude even if that altitude is still 2400
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I don't understand the confusion.... absent a lower depicted altitude, then the lowest already depicted for the prior segment governs. :dunno:
 
I was looking for another example with an off-airport VOR for the FAF, and with the PT depicted at the same altitude as the FAF crossing altitude. Most of the ones I found had the PT altitude higher, with a descending line inbound to the FAF and a lower altitude depicted.

Then, I found this one... and I think this is how Ron (and others) feel the chart SHOULD be depicted. Note that it has the same minimum altitude for the PT and the FAF crossing altitude, and a horizontal line.

Sure looks like the charting office messed up on the chart in the first post.
 
TangoWhiskey said:
I don't understand the confusion.... absent a lower depicted altitude, then the lowest already depicted for the prior segment governs. :dunno:
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Where is such an idea documented?

Normally there is a charted altitude at the FAF but on the NACO chart there is none and the line is slopped in the profile view all the way from the procedure turn inbound. That could be considered by some to mean that a descent is allowed once you are established inbound, to the MDA
 
Look at the last page of this document:

http://naco.faa.gov/content/naco/online/pdf_files/8th_IAP_Symbols.pdf

I'm beginning to see Ron's point. The FAF is for timing a non-precision approach, and to mark the beginning of the "final approach segment". On the diagram at the bottom of the IAP chart user's guide, they show a Non-Precision approach (VOR FAF), level inbound from 1600' PT. It sure appears that they should use a horizontal line if they want you to stay at that altitude til crossing; the originally discussed chart, as published, does indeed seem to indicate that you can start your way down to MDA anytime after PT inbound...

I can't find anything that references the FAF being a "change altitudes" or "begin descent to MDA" marker, unless it's specifically charted that way via a limiting altitude.
 
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TangoWhiskey said:
Look at the last page of this document:

http://naco.faa.gov/content/naco/online/pdf_files/8th_IAP_Symbols.pdf

I'm beginning to see Ron's point. The FAF is for timing only, and to mark the beginning of the "final approach segment". On the diagram at the bottom of the IAP chart user's guide, they show a Non-Precision approach (VOR FAF), level inbound from 1600' PT. It sure appears that they should use a horizontal line if they want you to stay at that altitude til crossing; the originally discussed chart, as published, does indeed seem to indicate that you can start your way down to MDA anytime after PT inbound...

I can't find anything that references the FAF being a "change altitudes" or "begin descent to MDA" marker, unless it's specifically charted that way via a limiting altitude.
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Did you also see that in each one of those examples the crossing altitude at the FAF is given if a descent is taking place? The only place a crossing altitude was not given was the example where the inbound altitude restriction is the same as the crossing altitude.

So the question still remains, should the line from the procedure turn be flat so that you cross the FAF at 2400 or should it be a descent with a crossing altitude at the FAF given. I have yet to find where you cross that Maltese cross without a reference altitude.
 
Well I was taught(maybe incorrectly) that once established on a particular segment you could descend to the lowest published altitude for that segment (step down fixes which you can't identify excluded). If, as I suggested earlier, the FAF in this procedure only exists for timing to the MAP, then 1580 is the number to go down to inbound.
Sure hope we get an answer on this.

Edit: I also saw the 2400 on the GPS procedure and thought that was interesting as well. Although they don't share the same approach corridor, probably with different obstruction criteria.
 
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Scott Dunham, a former controller now with NTSB, on AvSig provided this cite:


From TERPS...

234. INITIAL APPROACH SEGMENT BASED ON A PT. A PT shall be specified when it is necessary to reverse direction to establish the aircraft on an intermediate or FAC, except as specified in paragraph 234e. A PT begins by overheading a facility or fix which meets the criteria for a holding fix (see paragraph 287b), or for a FAF (see paragraph 287c). The procedure shall specify the PT fix, the outbound and inbound course, the distance within which the PT shall be completed, and the direction of the PT. When a teardrop turn is used, the angle of divergence between the outbound course and the reciprocal of the inbound course shall be a MINIMUM of 15° or a MAXIMUM of 30° (see paragraph 235a for high altitude teardrop penetrations). When the beginning of the intermediate or final approach segment associated with the procedure turn is not marked by a fix, the segment is deemed to begin on the inbound procedure turn course at the maximum distance specified in the procedure. Where neither segment is marked by a fix, the final segment begins at the maximum distance specified in the procedure.

However, in this case there IS a fix demarcating the final approach segment, and that's where the final approach obstacle clearance evaluation starts. You can't extrapolate an altitude established for the final approach segment out past the FAF - the PT is initial/intermediate, not final.

I'm open to other interpretations, but it looks to me like there is no way to go below 2400 until FAF inbound.


Great discussion as always. Great to see the egos parked while everyone tries to learn.

Best,

Dave
 
Dave, got any links to the TERPS? I haven't been able to find it.

I agree with the parking of ego's and trying to learn, this is great!
 
I was gonna ask if anyone had the jepp chart. Cutting through the crud the NACO is confusing plain and simple. That bothers me. I like Tim's response because its safest. Ron let us know what their response is.
 
Don Jones said:
I agree with the parking of ego's and trying to learn, this is great!
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Amen. It's what makes this blue board great to me. People are free to express their interpretations or understandings without fear of being belittled. Questions, gently, to lead to conclusions, yes, but rarely slammed.
 
Not a regulation or in terps or the AIM, but the FAA Instrument Flying Manual states that one may not descend to the MDA until the Faf on a non-precision approach. I'm traveling this week so I don't have access to the manual but I looked it up when this thread started. It was in the chapter on approaches when discussing approach plates.
 
alaskaflyer said:
Not a regulation or in terps or the AIM, but the FAA Instrument Flying Manual states that one may not descend to the MDA until the Faf on a non-precision approach. I'm traveling this week so I don't have access to the manual but I looked it up when this thread started. It was in the chapter on approaches when discussing approach plates.
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I thought so too, but reading that chapter (5) over and over in the new online PDF color version, I sure don't see it.
 
... the FAA Instrument Flying Manual states that one may not descend to the MDA until the Faf on a non-precision approach.
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Personally, I think the semantics of the profile view are "you may descend to the altitude restriction listed for the next step-down fix, or if you've passed the last step-down fix, then to the MDA".

I'm hearing an argument here that some of us are trying to insert an additional implied clause in the above, something like "unless the next fix is the FAF, and no explicit altitude restriction has been specified, in which case you should assume a continuation of the altitude restriction associated with the previous stepdown fix".

I don't think the above is implied, in any sense. It seems to be based on a notion that there must be an altitude restriction at the FAF, since that's where we begin our descent to MDA. This strikes me as backwards logic.

Ultimately, I believe that the argument is somewhat moot, because I don't believe that NACO would ever intentionally chart an approach with an "implied" altitude restriction at the FAF. So, in a sense, we're trying to interpret the semantics of an ambiguity that NACO, sensibly, never allows to exist in a chart, except when the chart is published in error.

So, in other words, the "right answer" is that you should immediately detect this chart as defective, and refuse to fly it, and certainly _not_ guess at what it's meaning is (except from the safety and comfort of your keyboard, of course).
-harry
 
Well, the response is back from my friends in the FAA -- it is indeed a charting error. There should be a 2400 at the VOR and the line from the PT to the FAF should be horizontal. IOW, it's supposed to be a level run at 2400 from the PT to the FAF, the Jepp chart is right, and the NACO chart is wrong. Also, there should be an "IAF" on the SVM VOR box. The only question now is whether an FDC NOTAM will be issued on this before the amended chart comes out in the Change Notice five weeks from now (the April 10 reissue is already in the customers' hands) -- I hope there is so nobody hits that tower.
 
Nice! I wonder how many cycles it would have been like that before someone caught it, or worse how long before the crash which called attention to it. I enjoyed the discussion on this one, we need more discussions like this.
 
!FDC 8/1204 1D2 FI/P CANTON-PLYMOUTH-METTETAL, PLYMOUTH, MI. VOR-A, AMDT 12... CORRECT PROFILE VIEW TO DEPICT INBOUND PROCEDURE TURN LEG AS A HORIZONTAL LINE WITH A MINIMUM ALTITUDE OF 2400 AT THE VORTAC; CORRECT PLANVIEW TO ADD IAF TO SALEM SVM VORTAC.
 
Ron Levy said:
!FDC 8/1204 1D2 FI/P CANTON-PLYMOUTH-METTETAL, PLYMOUTH, MI. VOR-A, AMDT 12... CORRECT PROFILE VIEW TO DEPICT INBOUND PROCEDURE TURN LEG AS A HORIZONTAL LINE WITH A MINIMUM ALTITUDE OF 2400 AT THE VORTAC; CORRECT PLANVIEW TO ADD IAF TO SALEM SVM VORTAC.
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That was FAST. This also encourages me to look more closely at IAP NOTAMS than I have in the past...
 
TangoWhiskey said:
That was FAST. This also encourages me to look more closely at IAP NOTAMS than I have in the past...
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I'll look at the NOTAMS a little more closely now. But one thing I have always done is prior to the flight I look over the approaches to my destination to see which ones I like better than others, to see what my option are if I have to change plans, and to see if any of the approaches have any gotchas (requirement equipment, strange routes, etc.)
 
Ron Levy said:
If your initial IR instructor never told you, let me tell you all now -- missing an FDC NOTAM can get you killed.
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...which is why during discussion of airspace I've told students to never depend on a NOTAM to determine if special use airspace is hot. Always call the controlling agency. Assuming everything is there can be as dangerous as not reading them at all.
 
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