Procedure Turn Question

luvflyin said:
I’d buy the house a round to be able to be in the back seat videoing the DPE saying, now do the ILS Approach, and the applicant saying ‘no’ I’m gonna do the RNAV Approach instead.
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I was doing the IFR cross country with a student. We were heading for the first approach, the LOC at KITR, on the Colorado plains. ATC gives him the NDB IAF (it's still there). Student says, "Request vectors to final." The controller laughed and explained that his radar coverage didn't go down that far.
 
midlifeflyer said:
I was doing the IFR cross country with a student. We were heading for the first approach, the LOC at KITR, on the Colorado plains. ATC gives him the NDB IAF (it's still there). Student says, "Request vectors to final." The controller laughed and explained that his radar coverage didn't go down that far.
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Not many of those remaining: On-airport NDB no-FAF (the sensor FAF notwithstanding).
 
aterpster said:
Not many of those remaining: On-airport NDB no-FAF (the sensor FAF notwithstanding).
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That's why I mentioned it was still there. Although I was referring to the LOC approach (as I recall, the localizer was picked up used when Stapleton closed), the NDB approach is still there too.
 
That is one old plate.

It shows 4 course radio range airways.
 
luvflyin said:
Sensor FAF. What’s that?
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One of the CNFs (computer navigation fixe) that exists only in the GPS database. In the case of a "sensor FAF" it gives the GPS a location on which to base prompts for the procedure turn. since there is no official FAF.

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Good basic description in the Instrument Procedures Handbook, although their use is broader than overlay approaches.

Computer Navigation Performance An integral part of RNAV using en route charts typically involves the use of airborne navigation databases. Because GPS receivers are basically “to-to” navigators, they must always be navigating to a defined point. On overlay approaches, if no pronounceable five-character name is published for an approach waypoint or fix, it has been given a database identifier consisting of letters and numbers. These points appear in the list of waypoints in the approach procedure database, but may not appear on the approach chart. A point used for the purpose of defining the navigation track for an airborne computer system (i.e., GPS or FMS) is called a Computer Navigation Fix (CNF). CNFs include unnamed DME fixes, beginning and ending points of DME arcs, and sensor final approach fixes (FAFs) on some GPS overlay approaches. (emphasis added)​
 
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aterpster said:
My question is about the underlined 14,100. That means the procedure turn entry zone has a floor of 14,100. You cannot descend below 14,100 until not only past QUIRT, but proceeding outbound. (AIM 5-4-9 a. 2.)
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In the AF we drilled into our students you could descent when "outbound, abeam, on a parallel or intercept course." The law of primacy being what it is, I'd start by descent when I hit QUIRT and finished my left turn and was tracking 007.
 
luvflyin said:
Maybe they oughta just do away with PT's and replace them with HILPT's. @RussR , would any HILPT template be contained within a PT template? Like maybe it wouldn't need to much calculation and Flight Check. It would have already been done.
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That's actually a fairly complicated question to answer generically, because the size of the PT and the size of the holding patterns vary based on different factors.

It's easy to answer on a case-by-case basis, though. At QUIRT at 14100, a holding pattern would indeed fit within the area evaluated for the PT. So if there was a policy to do wholesale replacement of PT with holds (without further evaluation), this specific PT could be replaced by a holding pattern with a minimum altitude of 14100. However, that poses a problem, doesn't it? Because now you're crossing QUIRT inbound at 14,100, which is obviously not going to work for the descent. The advantage that PTs have over holding patterns is that once you're on the inbound segment the evaluated area is smaller and therefore you can often go lower (like here). A holding pattern doesn't have that, it's one big oval and an obstacle (like a mountain) anywhere affects the whole thing.

But the holding pattern involved at QUIRT would actually be smaller than the PT, so with that in mind (and further evaluation and flight check), maybe it could result in a lower altitude that would work. Or, maybe that was tried and didn't work, where the PT does. It just all depends.
 
RussR said:
That's actually a fairly complicated question to answer generically, because the size of the PT and the size of the holding patterns vary based on different factors.

It's easy to answer on a case-by-case basis, though. At QUIRT at 14100, a holding pattern would indeed fit within the area evaluated for the PT. So if there was a policy to do wholesale replacement of PT with holds (without further evaluation), this specific PT could be replaced by a holding pattern with a minimum altitude of 14100. However, that poses a problem, doesn't it? Because now you're crossing QUIRT inbound at 14,100, which is obviously not going to work for the descent. The advantage that PTs have over holding patterns is that once you're on the inbound segment the evaluated area is smaller and therefore you can often go lower (like here). A holding pattern doesn't have that, it's one big oval and an obstacle (like a mountain) anywhere affects the whole thing.

But the holding pattern involved at QUIRT would actually be smaller than the PT, so with that in mind (and further evaluation and flight check), maybe it could result in a lower altitude that would work. Or, maybe that was tried and didn't work, where the PT does. It just all depends.
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Wouldn’t it be ok to make the HILPT 13100? You can start down to that at QUIRT. The 14100 comes from the RELAE Feeder. The other PT required Feeder is JAC at 15200. So it looks like the criteria for ‘high station’ is the lowest connection to the Enroute Structure. Having the HILPT altitude lower than that wouldn’t change that you are going to start at a higher altitude. Then, a HILPT like this would allow further descent once established inbound.
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luvflyin said:
Wouldn’t it be ok to make the HILPT 13100? You can start down to that at QUIRT. The 14100 comes from the RELAE Feeder. The other PT required Feeder is JAC at 15200. So it looks like the criteria for ‘high station’ is the lowest connection to the Enroute Structure. Having the HILPT altitude lower than that wouldn’t change that you are going to start at a higher altitude. Then, a HILPT like this would allow further descent once established inbound.
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The obstacle that affects the PT entry zone would affect the entire HILPT, so minimum holding altitude of 14,100. The PT works a lot better.
 
luvflyin said:
Wouldn’t it be ok to make the HILPT 13100? You can start down to that at QUIRT. The 14100 comes from the RELAE Feeder. The other PT required Feeder is JAC at 15200. So it looks like the criteria for ‘high station’ is the lowest connection to the Enroute Structure. Having the HILPT altitude lower than that wouldn’t change that you are going to start at a higher altitude. Then, a HILPT like this would allow further descent once established inbound.
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The published entry altitude of 14100 at QUIRT is not based on the minimum altitude on the feeder from RELAE. They are separate evaluations. In this case they happen to be the same - most likely the altitude from RELAE is driven by the PT entry altitude, not the other way around. Notice that from RELAE to QUIRT there isn't much high terrain, and it's really short. But a PT encompasses a huge amount of area, and will bring into consideration the mountains to the west. So the PT needs an entry altitude of 14100, and therefore the segment from RELAE to QUIRT is raised to 14100 as well (since you don't "climb" on an approach).

Your example at RAL is a special case, where a holding pattern oriented over the FAF is allowed to have a minimum altitude greater than the FAF altitude, but only up to 300 feet higher. So, not much help at JAC (since it would take more altitude difference to be worthwhile, and QUIRT isn't the FAF anyway).
 
RussR said:
The published entry altitude of 14100 at QUIRT is not based on the minimum altitude on the feeder from RELAE. They are separate evaluations. In this case they happen to be the same - most likely the altitude from RELAE is driven by the PT entry altitude, not the other way around. Notice that from RELAE to QUIRT there isn't much high terrain, and it's really short. But a PT encompasses a huge amount of area, and will bring into consideration the mountains to the west. So the PT needs an entry altitude of 14100, and therefore the segment from RELAE to QUIRT is raised to 14100 as well (since you don't "climb" on an approach).

Your example at RAL is a special case, where a holding pattern oriented over the FAF is allowed to have a minimum altitude greater than the FAF altitude, but only up to 300 feet higher. So, not much help at JAC (since it would take more altitude difference to be worthwhile, and QUIRT isn't the FAF anyway).
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Makes sense. I do recall that 300 foot thing now. Thanks
 
midlifeflyer said:
One of the CNFs (computer navigation fixe) that exists only in the GPS database. In the case of a "sensor FAF" it gives the GPS a location on which to base prompts for the procedure turn. since there is no official FAF.

View attachment 111681

Good basic description in the Instrument Procedures Handbook, although their use is broader than overlay approaches.

Computer Navigation Performance An integral part of RNAV using en route charts typically involves the use of airborne navigation databases. Because GPS receivers are basically “to-to” navigators, they must always be navigating to a defined point. On overlay approaches, if no pronounceable five-character name is published for an approach waypoint or fix, it has been given a database identifier consisting of letters and numbers. These points appear in the list of waypoints in the approach procedure database, but may not appear on the approach chart. A point used for the purpose of defining the navigation track for an airborne computer system (i.e., GPS or FMS) is called a Computer Navigation Fix (CNF). CNFs include unnamed DME fixes, beginning and ending points of DME arcs, and sensor final approach fixes (FAFs) on some GPS overlay approaches. (emphasis added)​
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Thanks. That reminds of the guy at Salinas who was having problems with his, I think it was a Garmin 750, putting him onto final above the Glideslope. What was happening is the 750 put the whole PT up as a Magenta line to follow doing the 'Barb.' It would put the barb out there 1 minute after the IAF. But then it would lead the turn by 15 seconds so you rolled out on that magenta Barb line instead of starting the turn 1 minute out. That kept everything in just close enough that he couldn't roll out on final below the Glideslope. I think it was here on POA we hashed that one out. Coupla years ago give or take.
 
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