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I'm trying to understand how an IFR flight an ACC (center) controller communicates the hand over to the pilot to contact local airport frequencies.

I tried listening LiveAtc but my English is not so good and I still have a couple of questions. I must emulate a center hand over to local destination frequencies, is this order correct for pickup the right frequency?

Approach (if present) Departure (if present) Tower

Is departure eligible if an approach frequency is not available? If approach is available, which ATC gives landing clearances, tower or approach?

Also at which distance from airport ACC should do the hand off to the approach frequency?

SentryRaven
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ntnll
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  • Is this for a "virtual artcc" or some other simulation activity? – casey Oct 22 '15 at 00:54
  • Yes I'm working on a free ATC plugin for X-Plane – ntnll Oct 22 '15 at 06:53
  • Why not go for real controllers in x-plane? VATSIM e.g. – SentryRaven Oct 22 '15 at 07:13
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    A lot of people simply is not ready for VATSIM or IVAO, or can't follows whole flight from start to the end, and for this reason, could run in troubles with communities. Virtual ATC is still an high requested feature in flight simulation, especially for newbies. – ntnll Oct 22 '15 at 12:23

1 Answers1

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In general, aircraft are handed over on frequency to the next controller via a simple instruction to change the frequency:

R: "Lufthansa One Two Tree, contact Langen Radar 128.550"
A: "Contact 128.550, Lufthansa One Two Tree"

The simplified order of contacted stations for a commercial flight, depending on availability and airspace structure is:

  • Delivery (if available)
  • Apron/Ground (if available)
  • Tower
  • Departure (if available, sometimes handled by Approach)
  • Enroute ACC/Center (multiple stations along the route)
  • Arrival/Approach
  • Director (if available / in use)
  • Tower
  • Ground (if available)

The point and altitude or flightlevel where the handoff is initiated is agreed upon in Letters of Agreement between the different sectors or ACC/ARTCC stations.

KAE Airspace Langen EDDK
(Source: SentryRaven - Own Work)

The above picture shows the airspace around Köln/Bonn (EDDK) Airport, with the Köln Arrival East (KAE) sector being actively displayed in black. The STAR entry / clearance limit fixes are GULKO and KOPAG, in the east. Most traffic not arriving via NOR VOR in the west will terminate at these two fixes, which also serve as the handoff fix between the center controller (Paderborn High, Taunus and/or Rhein Radar Upper Control) and the arrival controller responsible for Köln East Sector. The Letter of Agreement between those sectors states that traffic arriving to Köln/Bonn via GULKO and KOPAG is to be cleared to FL100 and cleared for the respective STAR out of GULKO or KOPAG. The handoff is initiated approaching FL100 and approaching the entry fix, before the sector boundary.

The handoff is therefore based on airspace structure and sector boundaries, not on a preset distance from the airport. While arrivals from the east are handed off at FL100 over GULKO and KOPAG, arrivals from the west at NOR VOR are handed off at FL140-FL170.

Landing and Take-Off clearances are issued by the Tower controller, as the approach controller is not necessarily based at the same airport but in most cases in a remote facility together with other approach and center controllers. They have no visibility of the airport and can thus not issue these clearances.

The handoff to Tower usually happens when the aircraft is established on the final approach segment of the published approach (usually after passing the Final Approach Fix (FAF)) or a visual approach to the runway.

The phraseology is the same as above:

R: "Germanwings Two Six Alpha, contact Tower 124.975"
A: "124.975, Germanwings Two Six Alpha"

SentryRaven
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  • I also should tell that I'm trying to simulate this behavior in a flight simulator, I should simplify the way to implement it, and I guess the best way to do it is to choose an average distance for the last ACC communication and hand-over to approach. Should be 20-30 nautical miles from airport, a realistic distance for trig this call? I understand it is incorrect, but unfortunately simulation requires approximation. – ntnll Oct 22 '15 at 07:50
  • @ntnll You can base the calculation on the following rule of thumb: TMA airspaces range up to FL100 or FL245, sometimes something in between. There is no general rule, but each country and each airport is differently. For each 10.000ft of descent, you need to calculate 30 NM. So a handoff from Center to Approach at FL200 would be 60-70 NM from the airport. A handoff at FL100 would be at 30-40 NM. – SentryRaven Oct 22 '15 at 07:52
  • thank you very much, I can't vote yet, but I accepted the answer, thanks you very much, for now I'll use rough calculation you suggest. In the future I'll try to implement some most efficient calculations – ntnll Oct 22 '15 at 12:28