losing altitude in holding pattern

[olasek]

I have a question about this VOR-DME approach at KALM.

http://www.airnav.com/depart?http://204.108.4.16/d-tpp/1010/05130VD3.PDF

Assuming flying the full approach with PT I would find it impossible to lose the necessary altitude, yet the comment on the chart seems to suggest that if I arrive at the VOR at 12000 ft I should proceed with the approach. I am assuming that if I asked ATC I would easily get permission to lose some altitude in the holding pattern before flying outbound from the VOR. I tried this approach in a simulator and in a light aircraft I simply find descending from 12000 ft (while at VOR) all the way to MDA during the course of this approach simply impossible without resorting to some kamikaze-like flying.

 

[W. Stewart]

Not a CFI-I, but my approach to this approach (sorry!) would be to ask ATC to descend in the hold at the VOR prior to proceeding outbound for the PT. The profile view has a notation to maintain 9300 or above until established on the outbound course, so I would try to descend to 9500-10,000 and proceed outbound and descend to 7,000 once established on the OB course. This would allow less-kamikazi maneuvering, as you put it.

Wells

 

[poadeleted20]

ATC is not supposed to clear you for an approach like this unless you're at an altitude which allows you to reach the PT altitude (7000 in this case) without descending at more than a 400 ft/nm gradient (300 optimum). The approach itself contains a minimum of 9300 until departing the VOR outbound, and with a typical 6 miles or so from VOR to initiating the PT, that would just within that limit -- and closer to the "optimum" gradient if you go out to 7 or 8 before starting the PT. You can choose to accept a clearance to start from a higher altitude, but ATC should not assign 12,000 feet until VOR outbound without your consent to a steeper-than-normal descent gradient.

That said, if you do accept that approach starting at 12,000, you may not enter such a hold for descent on your own -- you must obtain clearance to do that from ATC. Otherwise, once you depart the VOR outbound, you should not cross it again until on the final segment inbound to the airport.

All in all, this approach is a good example of why you have to study approaches ahead of time, lest you find yourself flailing around trying to descend in the PT or doing a screaming dive for the runway on the final segment as neither is a good thing to be doing.

 

[olasek]

Thanks for all the answers.
I actually made it work without doing anything excessively steep by extending my outbound leg. I simply made full use of the 10 NM radius limit (not from the VOR but from PAYNE in this case) and it all worked fine. Before I tried to make PT too soon (following directions from G1000 software) which did not give me enough room to descend properly.

 

[roncachamp]

I have a question about this VOR-DME approach at KALM.

http://www.airnav.com/depart?http://204.108.4.16/d-tpp/1010/05130VD3.PDF

Assuming flying the full approach with PT I would find it impossible to lose the necessary altitude, yet the comment on the chart seems to suggest that if I arrive at the VOR at 12000 ft I should proceed with the approach. I am assuming that if I asked ATC I would easily get permission to lose some altitude in the holding pattern before flying outbound from the VOR. I tried this approach in a simulator and in a light aircraft I simply find descending from 12000 ft (while at VOR) all the way to MDA during the course of this approach simply impossible without resorting to some kamikaze-like flying.

I don't see the problem. If you arrive at the IAF BWS at 12,000 MSL you've got more than 24 miles available to descend 6200' in order to reach the FAF PAYNE at 5800 MSL. That's less than 260'/mile, shallower than a standard 3 degree glideslope. Doesn't sound like kamikaze-like flying to me.

 

[roncachamp]

ATC is not supposed to clear you for an approach like this unless you're at an altitude which allows you to reach the PT altitude (7000 in this case) without descending at more than a 400 ft/nm gradient (300 optimum).

Where is that requirement placed on ATC? Would a pilot need to descend at more than 400 ft/nm if he was at 12,000 MSL at BWS?

The approach itself contains a minimum of 9300 until departing the VOR outbound,

No it doesn't, it requires a pilot to "Maintain 9300 or above until established outbound for PT." Let's say a pilot is approaching BWS at 12,000 MSL on the feeder route from PIO. He must maintain 12,000' until departing the VOR outbound. He can then begin to descend, he cannot descend below 9300 until established outbound on the BWS R-215.

and with a typical 6 miles or so from VOR to initiating the PT, that would just within that limit -- and closer to the "optimum" gradient if you go out to 7 or 8 before starting the PT. You can choose to accept a clearance to start from a higher altitude, but ATC should not assign 12,000 feet until VOR outbound without your consent to a steeper-than-normal descent gradient.

Where did you find this optimum descent gradient of 300 ft/nm while outbound for the PT? That's shallower than the optimum gradient for final approach, which is 318 ft/nm.

 

[poadeleted20]

Where is that requirement placed on ATC?

Who said it was a requirement?

Would a pilot need to descend at more than 400 ft/nm if he was at 12,000 MSL at BWS?

Yes, in order to make 7000 by the start of the PT.

No it doesn't, it requires a pilot to "Maintain 9300 or above until established outbound for PT." Let's say a pilot is approaching BWS at 12,000 MSL on the feeder route from PIO. He must maintain 12,000' until departing the VOR outbound. He can then begin to descend, he cannot descend below 9300 until established outbound on the BWS R-215.

You are correct -- I missed the "established" part of that.

 

[sba55]

Yes, in order to make 7000 by the start of the PT.

But he wouldn't need to be at 7000 at the start of the PT. And it wouldn't make sense to attempt to be at 7000 there, either, since he would still have >10 miles from the start of the PT to descent 1200' to 5800', which means you would have to change configuration quite dramatically in the first descent from 12k' to 7k' and then the next descent from 7'k to 5.8k' - these are almost the same distance but the first descent would be a lot steeper.

Personally, I would just have a nice and steady descent, starting at the VOR (making sure I'm not below 9300 until established outbound or below 7000' until established inbound). 600 fpm should do nicely, depending on how far you want to go outbound from PAYNE....

 

[roncachamp]

Who said it was a requirement?

You said, "ATC is not supposed to clear you for an approach like this unless you're at an altitude which allows you to reach the PT altitude (7000 in this case) without descending at more than a 400 ft/nm gradient (300 optimum)."

Call it what you want, but where does it say that?

Yes, in order to make 7000 by the start of the PT.

Where is the start of the PT?

 

[roncachamp]

Personally, I would just have a nice and steady descent, starting at the VOR (making sure I'm not below 9300 until established outbound or below 7000' until established inbound). 600 fpm should do nicely, depending on how far you want to go outbound from PAYNE....

Yeah, me too, and without any kamikaze-like flying.

 

[ghogue]

Thanks for all the answers.
I actually made it work without doing anything excessively steep by extending my outbound leg. I simply made full use of the 10 NM radius limit (not from the VOR but from PAYNE in this case) and it all worked fine. Before I tried to make PT too soon (following directions from G1000 software) which did not give me enough room to descend properly.

If you flew 10nm from PAYNE, you exceeded your PT limit by 4 miles. The 10 mile limitation is from the VOR, not PAYNE.

 

[sba55]

If you flew 10nm from PAYNE, you exceeded your PT limit by 4 miles. The 10 mile limitation is from the VOR, not PAYNE.

No, it's from PAYNE. Take another look at the plate - you'll see the 10NM circle, which is centered over PAYNE....

 

[roncachamp]

If you flew 10nm from PAYNE, you exceeded your PT limit by 4 miles. The 10 mile limitation is from the VOR, not PAYNE.

How did you determine that?

 

[Clark1961]

If you flew 10nm from PAYNE, you exceeded your PT limit by 4 miles. The 10 mile limitation is from the VOR, not PAYNE.

Ya might wanna check that...

 

[SkyHog]

How can you look at that chart and say its centered on anything but PAYNE????

 

[ghogue]

No, it's from PAYNE. Take another look at the plate - you'll see the 10NM circle, which is centered over PAYNE....

The 10NM circle has nothing to do with the PT distance.

How did you determine that?

BOLES is the IAF, not PAYNE.

Ya might wanna check that...

I have. PAYNE is the FAF, and not used until after the PT is completed.

How can you look at that chart and say its centered on anything but PAYNE????

The circle is centered on PAYNE, but the circle is not the PT distance limitation. The note above the PT altitude is.

 

[sba55]

The 10NM circle has nothing to do with the PT distance.

Yes, and that's because there isn't such a thing as a "PT distance" unless there are specific PT instructions on the plate, such as "1 Mile legs" or something along those lines.

In this case, though, that doesn't apply. The only restriction that is relevant here in the 10NM restriction, which clearly starts at PAYNE.

 

[Everskyward]

The Jepp chart is more explicit and makes it clearer (that is for those who don't find the NACO chart clear - actually I don't think it is very clear).

 

[ghogue]

Yes, and that's because there isn't such a thing as a "PT distance" unless there are specific PT instructions on the plate, such as "1 Mile legs" or something along those lines.

In this case, though, that doesn't apply. The only restriction that is relevant here in the 10NM restriction, which clearly starts at PAYNE.

The "PT distance" I refer to is the limit published in the profile view above the PT altitude. I did not imply that the PT distance was a mandatory distance, but, the max distance specified in the profile view.

The 10nm circle is for scale and although it is centered on PAYNE, it has no bearing on the PT. A procedure turn is the Initial Approach Segment and those begin at an IAF. In this case, BOLES the VOR. PAYNE is the FAF and does not come into play until after you complete the PT (within 10nm of the VOR in this case). There is no requirement or need to even fix PAYNE prior to the PT. It serves no purpose at that point.

Thanks iNdigo for the chart above.

 

[Clark1961]

The Jepp chart is more explicit and makes it clearer (that is for those who don't find the NACO chart clear - actually I don't think it is very clear).

It wouldn't be the first time NACO & Jep disagree. The Jep limitation is certainly within the NACO published limit.

Is the comment that the 10 mile ring is just for scale substantiated by any particular document? I'm at work and can't go digging around too much. It certainly wasn't what I was taught. I was taught that everything within the X mile ring was to scale but that wasn't the rings primary purpose.

 

[Palmpilot]

The 10nm circle is for scale and although it is centered on PAYNE, it has no bearing on the PT.

I notice that NACO charts with no procedure turns still have 10 NM circles, so it appears that you are right. The SFO ILS or LOC Rwy 28L is an example. The 10 NM circle is centered on the localizer FAF.

http://download.aopa.org/ustprocs/current/SW-2/sfo_ils_or_loc_rwy_28l.pdf

 

[sba55]

It wouldn't be the first time NACO & Jep disagree. The Jep limitation is certainly within the NACO published limit.

Is the comment that the 10 mile ring is just for scale substantiated by any particular document? I'm at work and can't go digging around too much. It certainly wasn't what I was taught. I was taught that everything within the X mile ring was to scale but that wasn't the rings primary purpose.

No, it's not documented anywhere in the main publications that the 10NM restriction starts somewhere in particular (eg., the chart user guide, IPH, IFH, etc.). There might be some obscure NTSB cases or FAA interpretations.

I would make my best guess. No obstacles in this case, the charted PT example goes right up to the 10NM circle.....

 

[sba55]

The "PT distance" I refer to is the limit published in the profile view above the PT altitude. I did not imply that the PT distance was a mandatory distance, but, the max distance specified in the profile view.

Oh ok...

The 10nm circle is for scale and although it is centered on PAYNE, it has no bearing on the PT. A procedure turn is the Initial Approach Segment and those begin at an IAF. In this case, BOLES the VOR. PAYNE is the FAF and does not come into play until after you complete the PT (within 10nm of the VOR in this case). There is no requirement or need to even fix PAYNE prior to the PT. It serves no purpose at that point.

Thanks iNdigo for the chart above.

I see what you are saying, but that can't be the whole story. PAYNE does come into play from the very beginning since it's the FAF and you have to fly to the FAF as part of the approach; you can't just skip it. So, in practice, you obviously couldn't fly to the VOR and start your PT immediately.

But I think the main question here is what the 10NM notation relates to. I'm not aware of any reference that says that it relates to the IAF; but I would be happy to be shown wrong and learn something!

 

[Palmpilot]

The SJC ILS or LOC/DME Rwy 30L is another example of an approach with a 10 NM circle, but no PT. I notice that the circle is not centered on the localizer FAF in this case, so that is apparently not a requirement.

http://download.aopa.org/ustprocs/current/SW-2/sjc_ils_or_loc_dme_rwy_30l.pdf

 

[olasek]

I simply see the PT being INSIDE the circle (NACO plate). Since it is drawn inside the circle I can only assume I can fly exactly as it is depicted - as long as I can fit my PT inside this circle I am legal. And the circle is centered at PAYNE.

 

[ghogue]

Oh ok...


I see what you are saying, but that can't be the whole story. PAYNE does come into play from the very beginning since it's the FAF and you have to fly to the FAF as part of the approach; you can't just skip it. So, in practice, you obviously couldn't fly to the VOR and start your PT immediately.

But I think the main question here is what the 10NM notation relates to. I'm not aware of any reference that says that it relates to the IAF; but I would be happy to be shown wrong and learn something!

Actually, it is the whole story in this situation. I didn't say anything about skipping over PAYNE, but it isn't a factor "from the very beginning", it's not a factor until almost the end of the approach i.e., the FAF. There is absolutely no function to PAYNE until after you have completed the PT and inbound to the FAF, PAYNE.

The 10nm circle is a scale/reference mark, and info inside it is to scale, however, as I've mentioned before, it has no connection to the PT. In practice, most procedures with PT's have the IAF in the center, but it's merely coincidental that the PT limitation distance and the circle are the same.

Take a look at the Santa Rosa, CA (KSTS) VOR RWY 32 approach. The circle is centered on the VOR, which is not the IAF, but the IAF is COATI, almost at the outer edge of the circle, and the PT distance is from COATI.

 

[olasek]

Folks who claim that the 10 nm limit for PT is to be measured either from the VOR or from the airport are dead wrong. Rod Machado in his Instrument's Pilot Handbook explains this well and clearly state that this is not the case. This point from which 10 nm is to be counted is depicted on the vertical profile as a broken line - in this case it is PAYNE. In this case we measure the PT distance limit from PAYNE. End of the case.

A good another example is approach VOR rwy 9 at Riverside (RAL). Again 10 nm PT limit is counted from the RIVYO, not VOR or airport.

http://204.108.4.16/d-tpp/1010/00769V9.PDF

 

[Everskyward]

Is the comment that the 10 mile ring is just for scale substantiated by any particular document? I'm at work and can't go digging around too much. It certainly wasn't what I was taught. I was taught that everything within the X mile ring was to scale but that wasn't the rings primary purpose.

PLANVIEW
The majority of instrument flight procedure charts contain
a reference or distance circle. In such cases only the data within
the reference circle is drawn to scale. This circle is centered on an
approach fix and normally has a radius of 10 NM, unless otherwise
indicated. When a route segment, outside the circle, is not to scale
the symbol interrupts the segment.

From http://www.asa2fly.com/files/updates/CUG7_update_for_web.pdf

That's what I could find for now...

 

[Clark1961]

The 10nm circle is a scale/reference mark, and info inside it is to scale,

I disagree with that interpretation. Look at the PT diagram. If it is limited to within 10 miles of the VOR then the outbound leg and PT diagram certainly isn't to scale.

Furthermore, what would be the point of a scale ring around the FAF but an unrelated limit on the PT? Aren't all significant obstacles supposed to be plotted within the X mile ring?

 

[ghogue]

Folks who claim that the 10 nm limit for PT is to be measured either from the VOR or from the airport are dead wrong. Rod Machado in his Instrument's Pilot Handbook explains this well and clearly state that this is not the case. This point from which 10 nm is to be counted is depicted on the vertical profile as a broken line - in this case it is PAYNE. In this case we measure the PT distance limit from PAYNE. End of the case.

A good another example is approach VOR rwy 9 at Riverside (RAL). Again 10 nm PT limit is counted from the RIVYO, not VOR or airport.

http://204.108.4.16/d-tpp/1010/00769V9.PDF

One more time. The VOR is the IAF (not PAYNE). A PT (the initial segment) is flown from an IAF, not the FAF. In your example, the reason the 10nm distance is from RIVYO is because it is the IAF, not because it is in the center of the circle. It does not matter if the PT is contained within the circle or not. They are not related except by coincidence.

I disagree with that interpretation. Look at the PT diagram. If it is limited to within 10 miles of the VOR then the outbound leg and PT diagram certainly isn't to scale.

Furthermore, what would be the point of a scale ring around the FAF but an unrelated limit on the PT? Aren't all significant obstacles supposed to be plotted within the X mile ring?

It's limited to within 10 miles of the VOR because it is stated as such in the profile view, i.e. "Remain with 10 NM" just above the PT altitude.

The point of the ring is that info within is to scale and a reference line for distance. And yes obstacles inside the ring are plotted and to scale, but not necessarily centered on the FAF, it can be other fixes as well.

Look at the example above for KSTS. COATI, the IAF is barely within the circle and the distance and the PT barb extends outside the circle.

 

[Everskyward]

Folks who claim that the 10 nm limit for PT is to be measured either from the VOR or from the airport are dead wrong. Rod Machado in his Instrument's Pilot Handbook explains this well and clearly state that this is not the case. This point from which 10 nm is to be counted is depicted on the vertical profile as a broken line - in this case it is PAYNE. In this case we measure the PT distance limit from PAYNE. End of the case

Here's an approach with lots of broken lines. What do you think you are supposed to remain within 10 miles of?

http://aeronav.faa.gov/d-tpp/1010/00504ILY19.PDF

 

[Clark1961]

It's limited to within 10 miles of the VOR because it is stated as such in the profile view, i.e. "Remain with 10 NM" just above the PT altitude.

But it doesn't define which fix is the basis for the 10 mile limit.

The point of the ring is that info within is to scale and a reference line for distance. And yes obstacles inside the ring are plotted and to scale, but not necessarily centered on the FAF, it can be other fixes as well.

But no obstacles are shown which would limit one to within 10 miles of the VOR. Do you see the point here?

And again, the outbound course and PT aren't drawn to scale if your claim of a 10 mile limit from the VOR is correct. The lack of drawing to scale on the outbound course and PT line contradicts either your claim about everything being drawn to scale within the 10 mile ring or your claim that the PT must be within 10 miles of the VOR. Which of your claims is false?

Look at the example above for KSTS. COATI, the IAF is barely within the circle and the distance and the PT barb extends outside the circle.

Three and a half miles is not "barely." Calm down just a bit and try to stay on point. Overstatement does nothing for your demonstrated self-contradictory position.

 

[Palmpilot]

Folks who claim that the 10 nm limit for PT is to be measured either from the VOR or from the airport are dead wrong. Rod Machado in his Instrument's Pilot Handbook explains this well and clearly state that this is not the case. This point from which 10 nm is to be counted is depicted on the vertical profile as a broken line - in this case it is PAYNE. In this case we measure the PT distance limit from PAYNE. End of the case.

A good another example is approach VOR rwy 9 at Riverside (RAL). Again 10 nm PT limit is counted from the RIVYO, not VOR or airport.

http://204.108.4.16/d-tpp/1010/00769V9.PDF

Rod Machado and Jeppesen might both be considered authorities on the subject, but their interpretations give differing answers with regard to the approach at KALM.

It's scary that there doesn't seem to be a definitive answer in FAA publications. The Aeronautical Chart Users Guide doesn't seem to have anything that settles it.

The Instrument Procedures Handbook, page 5-38, describes procedure turns as being completed "generally within 10 NM of the PT fix," but I haven't found a definition of "PT fix." If I had to guess, it would be the point on the profile view from which the descent into the PT is depicted.

 

[Palmpilot]

The VOR Rwy 06 Approach into APC is another one where this issue comes up. Is the PT fix the VORTAC, or JATPO?

http://download.aopa.org/ustprocs/current/SW-2/apc_vor_rwy_06.pdf

 

[olasek]

Rod Machado and Jeppesen might both be considered authorities on the subject, but their interpretations give differing answers with regard to the approach at KALM.

It's scary that there doesn't seem to be a definitive answer in FAA publications. The Aeronautical Chart Users Guide doesn't seem to have anything that settles it.

I agree, it is a bit disconcerting and I understand the argument that comes from the Jeppesen folks. Oh well, another mystery

 

[Everskyward]

If I had to guess, it would be the point on the profile view from which the descent into the PT is depicted.

That corresponds with Jepps' depictions. At KAPC they say from the VOR, at KJAC from QUIRT, which is another example where it is not the center of the circle. Also, unlike the first example, if you use QUIRT you go out further than if you use FAPMO.

I had never thought about this before because I have always used Jepp instead of NACO but I can see how it is confusing.

Note: The reference circle is also 15 nm here instead of the usual 10.

 

[ghogue]

But it doesn't define which fix is the basis for the 10 mile limit.
It's defined by the fact that the VOR is the IAF, and the PT distances are from IAF's. That's how approaches are designed.


But no obstacles are shown which would limit one to within 10 miles of the VOR. Do you see the point here?

And again, the outbound course and PT aren't drawn to scale if your claim of a 10 mile limit from the VOR is correct. The lack of drawing to scale on the outbound course and PT line contradicts either your claim about everything being drawn to scale within the 10 mile ring or your claim that the PT must be within 10 miles of the VOR. Which of your claims is false?


Three and a half miles is not "barely." Calm down just a bit and try to stay on point. Overstatement does nothing for your demonstrated self-contradictory position.

Neither are false. Not to split hairs, but I never said everything inside is to scale. Obstacles, terrain features and of course airports certainly are, but procdeure tracks are not necessarily. When approaches are drawn, the length of the procedure turn line can vary and not necessarily to scale. Look at a number of charts and you will see this. The Jackson Hole ILS or LOC RWY 19 above provides an example. The PT limit is 10nm, but one can see the actual length is less than 10 miles. My claim, as you put it, that the 10 miles is in reference to the VOR is correct for the reason that I have repeated all along. The VOR is the IAF and the PT is flown from the an IAF.

You say I need to calm down, but I fail to see anywhere in my posts that I'm anything but calm. There has been no overtatement and no self-contradictory positions by me. You are simply trying to make me appear irrational which I am not, to bolster your points.

 

[gismo]

I spotted a potential consistency WRT the reference point for the "remain within" note on the NACO charts. In all the examples posted so far, the reference point is depicted by the start of the solid heavy line leading to the PT on the profile view matches the Jepp chart's additional notation of said reference point for distance limits in the PT.

That said, I've never seen anything in writing that confirms my suspicion.

 

[TangoWhiskey]

Lance, you're correct; so is ghogue in this excellently educational thread. We should as instrument pilots have no confusion about where this "remain within 10 nm" distance starts. It could mean our lives.

ghogue's comment that the procedure turn is part of the INITIAL APPROACH SEGMENT is the key to understanding where to measure the "within 10 nm" from. I quote from the FAA's Instrument Procedure Handbook:

INITIAL APPROACH SEGMENT

The purpose of the initial approach segment is to
provide a method for aligning the aircraft with the
intermediate or final approach segment. This is
accomplished by using a DME arc, a course reversal,
such as a procedure turn or holding pattern, or by
following a terminal route that intersects the final
approach course. The initial approach segment
begins at an IAF....

He was entirely correct in noting that the 10nm "scale" circle centered on the FAF PAYNE on the PLAN VIEW has nothing to do the "remain within 10 NM" notation for the Initial Approach Segment's PT on the PROFILE view. They are distinct entities on the chart, though fact that the PT barb happens to be depicted inside the 10NM scale circle can understandably cause confusion.

The PT INITIAL Approach Segment leg must originate back at an INITIAL Approach Fix; as has been stated, one can find that by following the black line upslope on the profile view's outbound leg.

 

[roncachamp]

BOLES is the IAF, not PAYNE.

I have. PAYNE is the FAF, and not used until after the PT is completed.
The circle is centered on PAYNE, but the circle is not the PT distance limitation. The note above the PT altitude is.

So the ten mile limitation on the PT is from the IAF, not the FAF? What do you base that on?