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Course reversal on a GPS approach

Old 01-16-2011, 09:55 AM
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Default Course reversal on a GPS approach

If I'm doing a course reversal on a GPS approach with a hold style procedure turn and the hold is depicted as 4nm, do I also need go 4 nm out on the procedure turn?
I believe I do, but would like some confirmation.
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Old 01-16-2011, 10:55 AM
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I would say no, but I don't have anything regulatory to back that up.

I see no reason why you could not go less than 4nm provided you can become established before the holding/IF/IAF fix, but I would not go more than 4nm, unless you are assured the MSA extends beyond 4nm and you are at or above it.

Experts, the cyberspace is yours..........................

Last edited by N9373M; 01-16-2011 at 11:08 AM. Reason: Thunk about it and added the MSA caveat
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Old 01-16-2011, 10:57 AM
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Actually I agree with you now. i was overthinking it. You wouldn't go out 4 nm on a hold entry you'd just go the one minute or so. As long as you stay in the protected area the entry/course reversal wouldn't need to be 4 nm.
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Old 01-16-2011, 11:07 AM
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I added a caveat about MSA. Do you have a particular approach in mind, or just in general?

winds, a/c category/performance, etc could also be a factor

Another caveat - restricted airspace beyond 4nm. I gotta quit thinking.

good question!

Last edited by N9373M; 01-16-2011 at 11:20 AM.
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Old 01-16-2011, 04:13 PM
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It's kind of an interesting question and I've heard a lot of folks express different opinions about it with language fro the AIM they claim supports it.

I come down on the side of, if the hold is one that is time based, then the general 1-minute out and then start timing inbound to get as close to 1-minute inbounds as you can is the way to go.

But, if the hold is distance-based (including GPS holds), then you use distance to determine all of the outbounds, including the first. That's answer is not crystal clear from the FAA material but I get there when I think about holds that are =not= 4 nm.

Here's the RNAV 28 into KAPA.
http://aeronav.faa.gov/d-tpp/1101/05715R28.PDF

It has a co-located HILPT and MAPT at DOCKY with 7 nm legs rather than 4. The fact that it's not a standard length tells me that there's gotta be a reason for specifying a leg lenght. My guess is that the reason in this case is traffic separation component, since DOCKY is pretty much right on the approach path to DIA.

That suggests to me that ATC is anticipating that, if you have crossed DOCKY outbound, you're not going to turn inbound for 7 miles. And that you shouldn't (without permission anyway - 7 miles is a long time in a trainer and I generally ask ATC for shorter).
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Old 01-26-2011, 12:40 PM
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Not for the procedure entry according to the AIM. But as we all know, the AIM lists 3 'recommended' holding entry procedures and none of them are regulatory in nature.

If I were flying the entry, I would do the standard 1 minute outbound (winds depending) before doing the turn back inbounds. Be sure to stay in the protected area.

Once established in the hold, fly the 4NM holding pattern.

According to TERPS criteria, the holding pattern size for an RNAV or GPS is based upon the minimum holding altitude (7130.3A). This of course could change if military aircraft were flying (requiring a higher airspeed) which requires a larger template evaluation area, which typically results in an expanded pattern size due to picking up higher obstacles.
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Old 01-27-2011, 04:51 AM
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Originally Posted by clipperstall View Post
Not for the procedure entry according to the AIM.
Really? Where does the AIM say to use timing for the entry to a distance hold?

There is a note immediately following the description of timed holds that says
==============================
NOTE-
The initial outbound leg should be flown for 1 minute or 1 1/2 minutes (appropriate to altitude). Timing for subsequent outbound legs should be adjusted, as necessary, to achieve proper inbound leg time. Pilots may use any navigational means available; i.e., DME, RNAV, etc., to insure the appropriate inbound leg times.
==============================

But the very next paragraph says
==============================
5. Distance Measuring Equipment (DME)/ GPS Along-Track Distance (ATD). DME/GPS holding is subject to the same entry and holding procedures except that distances (nautical miles) are used in lieu of time values.
==============================

Not the clearest in the world, but the Note appears to be associated with the timed hold paragraph and the distance paragraph says to use distance instead of time for the entry as well as the rest of the hold.
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Old 01-27-2011, 05:26 AM
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That paragraph does not really indicate whether you use distances in lieu of the procedure entry. It is talking about the legs of the pattern.

If you were to use DME for an ATD hold using GPS, this begs the question about flying a certain DME on a holding entry when you are not established on a leg of the holding pattern but you are located somewhere in the protected area.

For example.. you enter a GPS 4NM holding pattern using a teardrop entry. How far will you know to fly before turning by using onboard GPS equipment? The distances of the pattern are based on the legs- not the area inside the protected zone.

The only way you would know when to turn is if your GPS is constantly giving you a distance away from the holding fix even after it switches to the hold mode.

---

If you read page 5-3-12 "Entry Procedures" it clearly states for parallel and teardrop entries to use time.

Parallel Procedure "...outbound on the nonholding side for one minute"

Teardrop Procedure "turn outbound to a heading for a 30 degree teardrop entry within the pattern (on the holding side) for a period of one minute..."

---

Ultimately, the AIM is non-regulatory and you can enter the holding pattern however you want. Just be sure to stay inside the protected area !

Last edited by clipperstall; 01-27-2011 at 05:42 AM.
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Old 01-27-2011, 06:03 AM
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AIM 5-4-9 Procedure Turn and Hold in-lieu of Procedure Turn
~~~
5. A holding pattern in lieu of procedure turn may be specified for course reversal in some procedures. In such cases, the holding pattern is established over an intermediate fix or a final approach fix. The holding pattern distance or time specified in the profile view must be observed. For a hold-in-lieu-of-PT, the holding pattern direction must be flown as depicted and the specified leg length/timing must not be exceeded. Maximum holding airspeed limitations as set forth for all holding patterns apply. The holding pattern maneuver is completed when the aircraft is established on the inbound course after executing the appropriate entry. If cleared for the approach prior to returning to the holding fix, and the aircraft is at the prescribed altitude, additional circuits of the holding pattern are not necessary nor expected by ATC. If pilots elect to make additional circuits to lose excessive altitude or to become better established on course, it is their responsibility to so advise ATC upon receipt of their approach clearance.

From what I can gather reading this paragraph (specifically the bolded and underlined sentences) it would seem that the FAA and NACO want pilots to fly the hold exactly as published with an additional emphasis on not exceeding the leg length limitations shown on the chart. This implies to me that they would like you to fly the hold legs (both entry and subsequent legs - as discussed in earlier postings) to the exact specs listed on the chart therefore, proceeding all the way out to 4 NM (for example) on a normal entry for a depicted hold on a normal GPS Approach.

Additionally...

FAA Instrument Procedure Handbook - Chapter 5, Page 5-39
~~~
". When a holding pattern is published in place of a procedure turn, pilots must make the standard entry and follow the depicted pattern to establish the aircraft on the inbound course"

The above passage is referring to the "Holding" Section in Chapt 5 of the AIM where it states (as noted in previous postings) that if a distance is noted instead of a time, then the entry and subsequent legs will be determined by distance instead of time as well.

Since the depicted pattern in question has a distance instead of a time shown, then I believe that this passage (and the reference to "standard hold entries" in the AIM) also favors using the whole depicted 4NM (for example) on a normal GPS hold.

Finally, as others have said, I do NOT believe that this is a 100% definitive explanation however, in my opinion, it would seem that the FAA and NACO are trying to tell us (in their noisy, convoluted Lawyer language) that we should do what it says on the plate and since it says 4NM on the plate, I will fly out to just a little prior to 4NM and then make my turn back inbound when doing this course reversal. I believe the one thing all of us can agree on is that a pilot will be safe AS LONG AS he/she remains WITHIN the 4NM on the outbound leg of the hold entry. If you turn early or right at 4NM, either way, you will be safe as long as you do not go beyond the 4NM limit.
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Old 01-27-2011, 06:13 AM
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What if you are doing a teardrop entry? You aren't on an 'established' 4NM GPS Leg.

That's my point.

Yes it makes sense for any entry using a DME leg with a specified distance to use that distance; however, what if you aren't on a leg at all?
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