How much protected airspace (hold)?

[a-v-8er]

While in a standard holding pattern how much protected airspace do you have? Holding side, non-holding side... distances (nm), other criteria?

I assume this could be found in the TERPS, but since I don't carry a reference like that around with me and can't seem to find the answer. Anyone care to try?

 

[Mr. Irrelevant]

I think it's 9 miles on the holding side, 4 on the non-holding but that's just a guess. I'd really like to know for sure too.


Mr. I.

 

[SierraPilot]

The space available for the hold is fairly standardized both as to length and size to each side of the inbound course. There is a primary area, maneuvering zone, and secondary area. The overall shape is like that of an elongated avocado cut in half lengthwise. The fix is on the course line. One nm away, at right angles to the course at the fix, is the center (nameless) of the radii for the small end of the avocado. A five nm 180 degree area of arc forms the small end of the avocado. Ten nm away on the outbound course there is another point (nameless) on the same side of the course but two nm miles from the course. The six nm radii from this point form the big end of the avocado. The offset from the course line of these two points gives both ends of the maneuvering zone. The course line is thus offset from the center line of the avocado by one nm on the small end and two nm on the big end.

Draw an avocado. The holding inbound course line is offset to the non-holding side one mile from the center of the arc of small end and is offset two miles to the non-holding side of the arc of the large end. The radius of the small end arc is 5 miles plus a two-mile secondary zone which extends like a heavy skin around the avocado. At its longest the avocado is 25 miles long. At the large end it is 15 miles wide and at the fix about 14 miles wide. The holding side gives us a over half an avocado that is 25 miles long, and widens from 7 miles to 10 miles on the holding side. The non-holding side is 23 miles long and 7 miles wide

 

[Vector4fun]

Years ago, when I worked at a non-radar approach control, we had a whole set of templates, numbered, in the shape of that "avacado". I had to re-draw the holding patterns and protected airspace a couple times on our controller charts, and as I recall, we had a table which referenced the likely holding speeds for the aircraft involved, and the likely altitudes, and dictated which number template you used. The faster the speeds, or higher the altitude, the bigger the template you used. We used to draw one set for props, and one for jets. Some years later, at my first radar facility, we did the same every couple years for reference if we lost radar. So the answer is, "Depends".

Over the past ten years or so, I can't recall even seeing such a chart. My present facility has dual ARTS processors, so one going down wouldn't put us in a non-radar situation, and if the radar site itself goes down, (such as for maint), then we use the CENRAP system to pull radar data from the Center's long-range sites. We don't even train or practice non-radar procedures any more, though we do have some basic measures written in our LOA with the Center.

We also don't hold at the primary airport, there's no room or reason for it. The only holding that goes on is GA at some of the secondary airports for wx or training. If we're 800 RVR and you're waiting for Cat I mins, I'm going to politely but firmly ask you to go some place at least 20-30 miles away to hold. I got other folks that want to use that localizer. and the "protected" airspace is going to be based on what experience has told me to allow, and what we negotiate as far as leg length....

 

[WrightAvia]

I've had to hold at this one secondary airport a quite a few times, as it is a peninsula on a peninsula and the visibility there is at the whims of wind direction and the upslope fog you get from it.

But anyway, at this airport the center keeps the holds above 4,000 feet to keep the holding aircraft in radar. Usually you can negotiate any type of hold or leg length you please from the controller, as we are not sitting on busy airways and traffic volume is low. I honestly think you could ask the controller to let you do a 4 or 40 mile DME arc around the VOR at this field as a hold and they wouldn't care if you went clockwise or counter clockwise. The fact that you are in radar and in controlled airspace while on an IFR flight plan, is your protected airspace.

At the primary airport that we use as a HUB, they did hold some aircraft, but it was no where near the airport. They had us all strung out in a serpentine conga line, that lasted at least 30 minutes, if not 40. I remember taking 360 degree turns at the request of ATC at least twice, all while in IMC conditions.

There was unforcasted fog at the airport (and the region) and it was catching alot of pilots off guard. I remember one major airline flight checking in with approach and he starts balking with the controller about being vectored for a hold. The controller told him he was number 23 in line. It finally got to the point where I was about one more vector away from declaring min fuel, when I was told I was being vectored for the down wind to the ILS.

 

[Andy Neill]

I think 80/20 had the definitive answers on this subject last March.

http://forums.flightinfo.com/showthread.php?s=&threadid=15535&highlight=holding

 

[a-v-8er]

The space available for the hold is fairly standardized both as to length and size to each side of the inbound course. There is a primary area, maneuvering zone, and secondary area. The overall shape is like that of an elongated avocado cut in half lengthwise. The fix is on the course line. One nm away, at right angles to the course at the fix, is the center (nameless) of the radii for the small end of the avocado. A five nm 180 degree area of arc forms the small end of the avocado. Ten nm away on the outbound course there is another point (nameless) on the same side of the course but two nm miles from the course. The six nm radii from this point form the big end of the avocado. The offset from the course line of these two points gives both ends of the maneuvering zone. The course line is thus offset from the center line of the avocado by one nm on the small end and two nm on the big end.

Draw an avocado. The holding inbound course line is offset to the non-holding side one mile from the center of the arc of small end and is offset two miles to the non-holding side of the arc of the large end. The radius of the small end arc is 5 miles plus a two-mile secondary zone which extends like a heavy skin around the avocado. At its longest the avocado is 25 miles long. At the large end it is 15 miles wide and at the fix about 14 miles wide. The holding side gives us a over half an avocado that is 25 miles long, and widens from 7 miles to 10 miles on the holding side. The non-holding side is 23 miles long and 7 miles wide

Well, I see that there's no simple answer to this... Just one more question that comes to mind when drawing this and lokking in the Holding Pattern Criteria 7130-3A. The pattern you describe has the same dimensions regardless of where or how high/low. Skimming through 7130-3A, seems like there are many different templates/patterns with different dimensions using the same model (avocado) as a basis (page 23). How can you tell which of these templates is used or is this somehow more standardized depending on area, location, altitude?... I seem to be missing something?

Here's the link to 7130-3A if anyone needs it:
http://av-info.faa.gov/terps/Directives_files/7130-3A.pdf

Thanks!

 

[a-v-8er]

*bump*

 

[Vector4fun]

A-V-8er,

I'm not sure I understand what you're asking. If you look at table 2 in the 7130-3, the template number is determined by the distance from navaid, max speed in the holding pattern, and holding altitude. All we ever did was select the proper template from the proper table, and then trace it on a controller or sectional chart.

 

[A Squared]

Sierrapilot (and a-v-8er)

What you've described with your Avocado shape is not the holding pattern protected area. It's the obstacle clearence area for a procedure turn. Good description of the PT area, by the way. As you're no doubt aware now, if you've looked at 7130.3, the holding pattern area is more of a "lemon" shape than an avocado, and yeah, there's no simple answer. If you really must know, follow the instructions in 7130.3

 

[A Squared]

OK, folks, this question got me wondering so I dug into 7130.3 and wound up drawing holding templates and measuring them (yeah, I know, I'm a little wierd)

Here's as close as I can come to a simple answer:

I drew the smallest template that is applicable to a standard hold, the template for 200 kt and 2000 feet, any higher hold would have a bigger template and any faster hold would have a larger template. Only a hold restricted to 175 knots would be smaller.

Here's what I found:

On the non-holding side of your holding course you have 3.2 NM of protection

On the Holding side of your holding course you have a minimum of 4.3 NM of protection.

On the non-holding *end* (ie: west end if you're holding east on the 90 radial) you have about 4 NM of protection.

On the holding end (east, when holding east) you have 9 NM of protection.

To put it a differnt way, If you draw a standard holding pattern to scale for 200 knots in the middle of the template, you have a minimum of 3 NM of protection from the hold pattern in all directions.

Does that help?

 

[dash8driver]

avacados and lemons.... now i'm gonna get hungry every time i have to hold!

 

[a-v-8er]

Thnx everyone! Makes more sense now...