Proposal to define aviation database pages...

[DaveNF2G]

I think TRACON frequencies should be listed for each airport served by the TRACON. A new scannist is unlikely to know that Pittsfield, MA, is controlled from Albany, NY, so they will not be looking out of state for approach frequencies. All they will find is tower and CTAF for Pittsfield.

The channel tags need to be explicit also. It is not sufficient to enter "Approach" as a tag unless it is the sole approach frequency used by the facility. There are very few approach-only channels anyway, because whether a pilot is talking to Approach or Departure on a given channel depends on the wind direction and which phase of flight is underway.

As for geotagging, I think we should leave well enough alone with respect to breaking down service areas by compass direction from the airport. Even though the FAA does it that way, the scanner listener generally wants to know where to monitor the local airport traffic - all of it. Besides, do you actually know what zip code you would be in if you wanted to monitor aircraft departing over your head at an unfamiliar airport?

 

[b52hbuff]

I think TRACON frequencies should be listed for each airport served by the TRACON. A new scannist is unlikely to know that Pittsfield, MA, is controlled from Albany, NY, so they will not be looking out of state for approach frequencies. All they will find is tower and CTAF for Pittsfield.

The channel tags need to be explicit also. It is not sufficient to enter "Approach" as a tag unless it is the sole approach frequency used by the facility. There are very few approach-only channels anyway, because whether a pilot is talking to Approach or Departure on a given channel depends on the wind direction and which phase of flight is underway.

As for geotagging, I think we should leave well enough alone with respect to breaking down service areas by compass direction from the airport. Even though the FAA does it that way, the scanner listener generally wants to know where to monitor the local airport traffic - all of it. Besides, do you actually know what zip code you would be in if you wanted to monitor aircraft departing over your head at an unfamiliar airport?

I'm postponing the discussion on TRACON until we get consensus on Class B/C airspace. And there are a couple of other airfield issues we haven't discussed, but I'll post after we're done with current topic.

Here are the descriptions from the terminal charts?
SkyVector: Flight Planning / Aeronautical Charts

In my local example all frequencies should be called NORCAL Approach. Beyond putting the compass heading (either N/S/E/W or degrees) as was done by the terminal chart I showed above, what else do you want to add?

Once all of the NORCAL frequencies are tagged with a compass heading, the only other description is 'Departure' and '(IC)'. Within the overall NORCAL table, they are all Approach. It is understood that they are Approach/Departure. And within the field specific db entry, the only thing to add is '(IC)' for Initial Contact, or 'Departure' if one of the frequencies is Departure only. If it is combined Approach/Departure, what benefit is there in labeling it? Isn't dual use understood?

Here is the airnav entry for SJC, which sits in SFO's Class B:
AirNav: KSJC - Norman Y. Mineta San Jose International Airport
NORCAL APPROACH: 120.1 125.35 134.5
NORCAL DEPARTURE: 121.3
CLASS C: 121.3(280-080) 135.2(136-279)
CLASS C IC: 120.1(081-135)
IC: 120.1 257.6

 

[kma371]

I agree with this post the most.

Each airport page needs only that airports approach and departure control listed.

A radius of 15 miles for the approach/departure control and 5-7 miles for the airport it self (for when aircraft is on final or transistioning through).

Doing anthing more than that is overkill. If one freq is approaches from the east, then the description or alpha tag is sufficient. Geotagging based on an area only to the east is a bit much.

I think TRACON frequencies should be listed for each airport served by the TRACON. A new scannist is unlikely to know that Pittsfield, MA, is controlled from Albany, NY, so they will not be looking out of state for approach frequencies. All they will find is tower and CTAF for Pittsfield.

The channel tags need to be explicit also. It is not sufficient to enter "Approach" as a tag unless it is the sole approach frequency used by the facility. There are very few approach-only channels anyway, because whether a pilot is talking to Approach or Departure on a given channel depends on the wind direction and which phase of flight is underway.

As for geotagging, I think we should leave well enough alone with respect to breaking down service areas by compass direction from the airport. Even though the FAA does it that way, the scanner listener generally wants to know where to monitor the local airport traffic - all of it. Besides, do you actually know what zip code you would be in if you wanted to monitor aircraft departing over your head at an unfamiliar airport?

 

[b52hbuff]

I agree with this post the most.

Each airport page needs only that airports approach and departure control listed.

A radius of 15 miles for the approach/departure control and 5-7 miles for the airport it self (for when aircraft is on final or transitioning through).

Doing anthing more than that is overkill. If one freq is approaches from the east, then the description or alpha tag is sufficient. Geotagging based on an area only to the east is a bit much.

Maybe I was confused. I was thinking we were talking about having a single complete NORCAL page (as a working Class B/C example) that we link to from the individual airports. Or we break up NORCAL for the approach that is used at a specific airport.

My preference is that we do both. Do you think having both is overkill? Or are we just going to have the specific NORCAL frequencies in use listed in the airport pages?

My other question is how do you propose we define the distances? I know you've specified them in this post, but what is the source of your data?

My preference is that we go back to the FAA data (even if it transitions through Wikipedia, for accessibility/readability), and use their definitions for a Tower, Class B and Class C airspaces.

Here is a readable reference:
FAA National Airspace System Power Point Presentation
Or the base ppt:
http://www.usarmyaviation.com/study...uments/Airspace&download=Airspace Class 1.ppt

If you look at the Terminal Area chart:
SkyVector: Flight Planning / Aeronautical Charts

...it says to contact NORCAL (Class B) App within 20nm
20nm = 23.015589 statute miles

Here is a map of Fresno Air Terminal, it is a Class C airport:
SkyVector: Flight Planning / Aeronautical Charts
...it has a smaller radius.

Here is the FAA pub:
http://www.faa.gov/air_traffic/publications/atpubs/aim/Chap3/aim0302.html

3-2-4. Class C Airspace

a. Definition. Generally, that airspace from the surface to 4,000 feet above the airport elevation (charted in MSL) surrounding those airports that have an operational control tower, are serviced by a radar approach control, and that have a certain number of IFR operations or passenger enplanements. Although the configuration of each Class C airspace area is individually tailored, the airspace usually consists of a 5 NM radius core surface area that extends from the surface up to 4,000 feet above the airport elevation, and a 10 NM radius shelf area that extends no lower than 1,200 feet up to 4,000 feet above the airport elevation.

My read is that a 10nm or 11.5 statue mile radius is appropriate.

3-2-3. Class B Airspace

a. Definition. Generally, that airspace from the surface to 10,000 feet MSL surrounding the nation's busiest airports in terms of IFR operations or passenger enplanements. The configuration of each Class B airspace area is individually tailored and consists of a surface area and two or more layers (some Class B airspace areas resemble upside-down wedding cakes), and is designed to contain all published instrument procedures once an aircraft enters the airspace. An ATC clearance is required for all aircraft to operate in the area, and all aircraft that are so cleared receive separation services within the airspace. The cloud clearance requirement for VFR operations is "clear of clouds."

So in this case, we need to look at the charts, but the San Fran Area chart indicates a 20nm contact for NORCAL (Class B)approach.

The Tower is typically Class D airspace:

3-2-5. Class D Airspace

a. Definition. Generally, that airspace from the surface to 2,500 feet above the airport elevation (charted in MSL) surrounding those airports that have an operational control tower. The configuration of each Class D airspace area is individually tailored and when instrument procedures are published, the airspace will normally be designed to contain the procedures.

For SFO, I got this Instrument Approach Procedure from the main SFO page on airnav:
http://204.108.4.16/d-tpp/1010/00375IL19L.PDF
...note it shows a 15nm radius.

If we go to an IAP for SMF, we have a smaller airport and a smaller tower control radius:
http://204.108.4.16/d-tpp/1010/05490IL34L.PDF


So my point here is that we can get the information we need to define the official diameter of the geotag. Why would we want to geotag the radius smaller than the defined maximums?

 

[kma371]

I don't think we need to duplicate it.

20 miles could be better for approaches, and 10 for airports themselves. Otherwise we are making it more complicAted then it needs to be.

 

[b52hbuff]

I don't think we need to duplicate it.

20 miles could be better for approaches, and 10 for airports themselves. Otherwise we are making it more complicAted then it needs to be.

Where do you see the complication?

Just to be clear, the proposal says that airports have two classes of frequencies. These classes will be mapped into two subcategories, generically, these are Field and Approach. Field and Approach geotags share a common centerpoint at the airport in question. Fields (or airports) get one radius and approaches get another larger radius .

In my mind this concept is 'universal'...

Where do you see the complexity? Getting the distance numbers?

If you setup the defaults. I'll do the legwork to get the real dimensions of the service areas and submit them as updates. Once they are 'done', this isn't data that will change in a loooooong time.

And one other nit, the distances should be 11.5 statute miles and 23 statute miles. Geotags are specified in statute miles and airport data is presented in nautical miles. I found a conversion here:
CONVERSION*FOR NAUTICAL AND STATUTE MILES - BoatSafe.com

 

[kma371]

The complexity is every airport doesn't need to be different numbers. We don't have to have exact. We are hobbyists, not the ATC themselves, so actual airspace shouldn't be that much of a priority. I see and understand what your saying, but if we just pick a standard, 10 for airports, 20 for approach (a nice rounded number instead of 11.5 and 23), that is the best bet.

Where do you see the complication?

Just to be clear, the proposal says that airports have two classes of frequencies. These classes will be mapped into two subcategories, generically, these are Field and Approach. Field and Approach geotags share a common centerpoint at the airport in question. Fields (or airports) get one radius and approaches get another larger radius .

In my mind this concept is 'universal'...

Where do you see the complexity? Getting the distance numbers?

If you setup the defaults. I'll do the legwork to get the real dimensions of the service areas and submit them as updates. Once they are 'done', this isn't data that will change in a loooooong time.

And one other nit, the distances should be 11.5 statute miles and 23 statute miles. Geotags are specified in statute miles and airport data is presented in nautical miles. I found a conversion here:
CONVERSION*FOR NAUTICAL AND STATUTE MILES - BoatSafe.com

 

[cipher66]

The while I know people say 10 Statue miles, I have contacted a tower 20 Nautical Miles out because I know it's a busy place or because I can.

Agreed, that sometimes I have seen A/C be handed off to Twr at the 15-18 miles out range, normally during non peak periods in VFR conditions. I would not be opposed to increasing the Airfield ATC out to 20 NM but no more than that, I feel, would be realistic. Under no circumstances should the Airfield ATC database entries be given a radius less than what the official airspace service area is.

One more thing on alphatagging for TRACONs.... I personally feel that the alpha tag should have the name of the App or Dep sector and it's "primary" function. Example: Saint Louis Approach: 132.125 is known as Feeder North or (FN). therefore I would not be opposed to calling it "STL Approach (Feeder North)" Now, departures at STL are not just departures but also initial approach to "other than STL airports" like Scott AFB. Scott inbounds (except from the East/South) are handed off from ZKC to STL Dep 119.15 or 128.1. In these circumstances I would name it "STL App/Dep (Departure North)". If you look at the airnav database it shows these (or not, as many App freqs are not officially published in Airnav).

I'll be off the boards tomorrow, but will be checking in every once in a while...

 

[b52hbuff]

(or not, as many App freqs are not officially published in Airnav).

Where else to get 'unpublished' approach frequencies? How do the pilots get them?

 

[wise871]

Were I work we get our info from the US IFR Supplement. We get an updated set every 8 weeks. And if it's not in the book, we can get it from the flight planning office.

Where else to get 'unpublished' approach frequencies? How do the pilots get them?

 

[b52hbuff]

Were I work we get our info from the US IFR Supplement. We get an updated set every 8 weeks. And if it's not in the book, we can get it from the flight planning office.

I'd love to see an example of something that isn't published.

SkyVector: Flight Planning / Aeronautical Charts

...is another resource for maps. You can get approach frequencies from it. Not as handy as the tables, but if worst comes to worst...

 

[kma371]

I remember a link where you could download the IFR supplements, I'll look for it.

 

[b52hbuff]

I remember a link where you could download the IFR supplements, I'll look for it.

THe military ones were yanked quite a bit ago.
https://www1.nga.mil/ProductsServices/Aeronautical/Enroute/Pages/default.aspx

Now you need to be a qualified user.

 

[kma371]

THe military ones were yanked quite a bit ago.
https://www1.nga.mil/ProductsServices/Aeronautical/Enroute/Pages/default.aspx

Now you need to be a qualified user.

Nah, there is a guy that still posts them somewhere.

EDIT: Well, his link is now password protected. I have one from around April if you want it.

 

[DaveNF2G]

We get "unpublished" aviation frequencies the same way we confirm the published ones - listen to the handoffs with a scanner.

Linked pages would help to reduce redundancy in the database, but it would not serve the dowloader or the HP-1 user. That is the reason I proposed listing the regional A/D channels with each airport served.

Also, we should not assume that anything is "understood" by a scannist, particularly a newbie. If we know something, then it should be specified in the data.

 

[b52hbuff]

We get "unpublished" aviation frequencies the same way we confirm the published ones - listen to the handoffs with a scanner.

Linked pages would help to reduce redundancy in the database, but it would not serve the dowloader or the HP-1 user. That is the reason I proposed listing the regional A/D channels with each airport served.

I think we're all agreed then. We're going to have two copies of the approach frequencies. One global set and another per-airport set. The original proposal that started this thread describes two copies.

Actually, the global list would still be useful. When I hear an airplane at 4am, it would be useful to be able to scan all approach frequencies. Not much traffic at 4am and better to get all frequencies instead of fumbling around the per-airport selections...

 

[ootsk35]

Normally a pilot HAS to contact a TOWER no later than about 5 miles. I'm specifically leaving off the NM or SM because at that distances it's so minute.

Think of it this way.
Class G - 10 Miles
Class E - 10 Miles
Class D - 5 Miles
Class C - 20 Miles
Class B - from 20 - 50 miles

Yes, even though they are non-towered airports the FAA recommends that you monitor and transmit on the common traffic advisory frequency no less than 10 miles out from the airport.

As far as the towered airports contact 10 miles out, when contacting the tower. Approach control is when you get into greater distances from that.

 

[kma371]

I think we're all agreed then. We're going to have two copies of the approach frequencies. One global set and another per-airport set. The original proposal that started this thread describes two copies.

Actually, the global list would still be useful. When I hear an airplane at 4am, it would be useful to be able to scan all approach frequencies. Not much traffic at 4am and better to get all frequencies instead of fumbling around the per-airport selections...

Two copies? Like duplicated info?

How about one in a wiki and one in the DB, is that what you mean?

 

[b52hbuff]

Two copies? Like duplicated info?

How about one in a wiki and one in the DB, is that what you mean?

Yeah, I was thinking of two database copies, one in the DB and one in the airport page. My concern about the wiki is that it isn't as controlled as the DB. And having the DB in two ways would be great for scanners as well. As I said, sometimes you want to scan NORCAL and sometimes you want to scan the airport.

An analogy is to see what is done in the public safety area. If you look here:
Santa Clara County, California (CA) Scanner Frequencies and Radio Frequency Reference
...you see that BAYMACS is put in San Jose's radio lineup.
460.02500 RM 179.9 PL SJ10 BAYMACS (UHF CLEMARS) - Repeater FM Interop

...*and* it is also in the Mutual Aid/EOC section. Two different organizations for two different kinds of monitoring. Why isn't the Mutual Aid/EOC section a wiki?

 

[kma371]

Yeah, I was thinking of two database copies, one in the DB and one in the airport page. My concern about the wiki is that it isn't as controlled as the DB. And having the DB in two ways would be great for scanners as well. As I said, sometimes you want to scan NORCAL and sometimes you want to scan the airport.

An analogy is to see what is done in the public safety area. If you look here:
Santa Clara County, California (CA) Scanner Frequencies and Radio Frequency Reference
...you see that BAYMACS is put in San Jose's radio lineup.
460.02500 RM 179.9 PL SJ10 BAYMACS (UHF CLEMARS) - Repeater FM Interop

...*and* it is also in the Mutual Aid/EOC section. Two different organizations for two different kinds of monitoring. Why isn't the Mutual Aid/EOC section a wiki?

Well, the best way to do that (it's what I do) is create a system for NORCAL and a system for airports and turn them off and on as needed. I DO NOT think duplicating is the answer and I think that's the opinion of the DB admins as well.

It's really not all that simple to completely duplicate information from one location to another (unless it's just a hyperlink, which could be an option)

Admins have discussed creating state and nationwide listings for mutual aid frequencies so your example is going to be a thing of the past shortly.