iFly GPS Forum

As for why we sometimes have to check the charts: Well, for an example, I just took off "IFR" from Seligman, AZ a few days ago. Seligman doesn't have an IAP. Nor an ODP. Nor a tower, Nor anything. (Multicom.) Hence, nowhere to look up an Approach (or Departure) freq. It's uncontrolled airspace at the surface (that is, IFR is not being controlled), so I had to fly my way to a nearby intersection in controlled airspace and pick up my clearance with ABQ Center from there. To find the Center freq, I had to look on the IFR chart.

However, it turns out that Seligman is close the boundary between LA and ABQ Center. Had I been headed westbound, LA Center would have been the one to call.

Otherwise, I generally don't use FF around Arizona. Often times we're too low for RADAR coverage (6500', sometimes even 8500' is too low). When I am high enough for coverage and flying at night, then I might try to pick up FF from LA Center on the way back from CA to AZ. For that case, I have to look it up on the IFR chart too.

In the old days, when I didn't have electronic charts, and might not have had IFR charts with me for the route, I would call FSS and ask them what the freq was for Center. That still works too.

And one might need to look up a freq to get back on the air if one misdialed and hosed up during the chain of ATC handoffs. I hear that happening to Airliners a lot on Guard.

Of course, it would be easier to look up pertinent freqs on iFly if it had it. But, as above, for some airports, it's not always clear what the correct freq is.

Since we have some thread drift here anyway, I'll contribute:

Getting a Center frequency is no magic bullet. All US airspace to FL600 except Class G is owned by someone. That someone may be an ARTCC sector controller, a TRACON sector controller or a tower. Tower airspace is defined in a published FAA list, though I don't have the citation handy. TRACON airspace, however, is defined by MOUs between the TRACONs and the relevant ARTCCs. ARTCCs define their own sector structures. TRACONs do the same for the airspace that they have been given. Sometimes it is a little messy, as when a TRACONs airspace is on an ARTCC boundary. In the midwest and East, at least, it it very common for TRACON airspace to abut another TRACON's airspace. In these areas it is not uncommon for an entire multistate bugsmasher flight to be worked from TRACON to TRACON, never talking to a center controller. Oh, and BTW, it is not at all uncommon for a Class D tower to have a radar room and a TRACON.

So an initial callup to Center when, for example, you are in the area of South Bend IN at bugsmasher altitudes you will get instructions to contact South Bend approach. When transitioning into that area under ARTCC control, you will get shipped not to another Center controller; you will get shipped to SBN. Leaving SBN's jurisdiction you will get shipped either to another TRACON or to Chicago (IIRC) Center.

None of this is published AFIK and I doubt that an AFSS briefer will know it either.

Said another way, getting a Center frequency -- regardless of source -- gets you a best guess, but not anything more.

Not necessarily. TRACON-controlled airspace is AFIK always much larger than the airspace of an associated airport. IIRC an 80 nm. diameter cylinder is typical. And there are large TRACONs like SoCal and Potomac that aren't even associated with airports.

When you get high enough, above the tower and TRACON airspace, and into Class A I think the controlling entity is always an ARTCC but I suppose it is possible that there are some military airspaces that stay under military control all the way up to FL600.

I'm not sure how TRSAs fit into this -- whether approach control for a TRSA actually owns any airspace or not. Probably they do, as I think IFR aircraft are required to talk to them. I don't think I've ever flown into a TRSA under IFR.