For one of our research projects, we want to simulate a north atlantic flight from Frankfurt, Germany to the U.S.. To make it realistic, we are also simulating air traffic control - both instructions and clearances for the flight to be simulated as well as for all other flights on the same frequency. Now we were wondering, how "dense" is voice radio chatter over Europe (mainly Maastrict UAC and Scottish UAC) and over the North Atlantic (with CPDLC - Controller Pilot Data Link Communication in use)? In other words, how many transmissions per hour do pilots listen to in the given regions (approximately and in average)?

Please note, this question is not only about radio transmissions regarding the own flight, but transmissions from all flights on a given frequency that pilots listen to.

While this likely depends heavily on day and time, let's consider a typical weekday, departing Frankfurt around 10am local, so a time frame 1000Z - 1400Z for the above named regions would be of interest.

Can anyone, potentially a pilot regularly flying such a route, give some estimates?

  • 2
    $\begingroup$ I can't answer your question directly but as part of your research it might be a good idea to have a look at www.liveatc.net where you can listen in to ATC broadcasts live. You could even count the transmissions yourself and it'll give you a good idea of what goes on in the air. $\endgroup$
    – Cooper
    Apr 20, 2018 at 9:20

1 Answer 1


It helps to check prior research in that field, for example, VOCALISE: Assessing the impact of data link technology on the R/T channel (2005).

Quantitative aspects of pilot-controller communication are addressed in two en-route air traffic control studies: the VOCALISE study in a real operational environment (Graglia and al., 2005), and the EEC study in a simulation environment (Hering, 2001).

The VOCALISE study shows that on average 324 speech acts between controllers and pilots were recorded per hour in an en-route sector, or about 5 per minute.

(Source: Eurocontrol)

So for the en-route portion, a single sector/frequency deals with about 5 transmissions per minute. Note that some of the transmissions would fall under miscommunication, such as:

  • Incorrect read-backs
  • Call-sign confusions
  • Initiation failure
  • Understanding failure
  • Memory failure
  • Information failure
  • Omissions
  • Redundancies

An example breakdown:

[Out] of the incorrect read-backs, 30% are simple "say again" requests, and another 30% requests for repetition or confirmation of route information.

So that's another aspect to include in the simulation you'll be conducting.

  • $\begingroup$ thank you. I have seen the VOCALISE project before, however unfortunately I cannot judge if those values represent a good estimate for the sectors I'm interested in. I assume, Scottish UAC control sectors have a lot less speech acts... $\endgroup$
    – Stefan
    Apr 20, 2018 at 14:26
  • $\begingroup$ @Stefan - Judging by Terry's experience over Scotland, they probably get more say agains compared to other ACCs :) $\endgroup$
    – user14897
    Apr 20, 2018 at 15:28

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .