A Demo On How Data Comm Is Going to Make Flying Better

Air Traffic Control, UPS

Back in May I wrote about how airlines, air traffic controllers, and the Federal Aviation Administration (FAA) were all getting excited about Data Comm and how it was going to improve air travel. The FAA has now flipped it on at LAX, and I was invited to get a real demonstration of how it works both in the tower and on a UPS 767. I know a lot of you had questions after the last post, and I think most of them can now be answered.

Data Comm is specifically about giving clearances to pilots. Traditionally, this is handled by talking over the radio. Data Comm, however, is like a text message. And yes, to answer a question from the last post, this uses CPDLC. Airlines use this to communicate with US air traffic controllers over long stretches of water already. It’s now been given a a sexier name. (I didn’t say it was sexy, just sexier than CPDLC.) This technology is awesome for several reasons, not the least of which being that the controller shortage can now be resolved by hiring teenage girls with cell phones.

Air Traffic Control Kids

The FAA is racing to install Data Comm technology in the big towers in the US in short order. It will also be installed in the centers that handle flights in the air starting in 2019. Airlines need to install this on their aircraft as well in order to use it. Some are further along than others.

Since this is used overwater, most international aircraft have it installed. It’s domestic airplanes that might not. Though I didn’t get specifics by airline, I think it’s safe to say that the older the airplane, the less likely it is to have it. Airbus also makes modifications much more expensive than other manufacturers, so that hurts the rollout. Further, even if international aircraft have it installed, there’s still a fairly simple process they need to do to start using it for clearances. Not all have bothered.

Here’s how it works. Today, flight plans are shared between airline dispatchers and air traffic control. The dispatcher also sends the flight plan directly to the aircraft. Air traffic control sends these on to the towers at each airport, and they print them out on flight strips. (Yes, they still use paper, incredibly.)

Flight Strip ATC

The controller will call up the pilots of the aircraft and deliver the clearance. This includes more info which the pilots may not have in their systems. There could also be changes to the original plan which the controllers would convey. The instructions can be fairly complicated. Here’s the example the FAA played for us.

Keep in mind that they’re talking very slowly and clearly with no discernible accent. Try doing this at JFK with a controller who has a thick Long Island accent. Then try having the pilot be foreign as well. This can get painful. (I’m sure someone who loves LiveATC can link to some awful example.)

Now let’s look at Data Comm. Instead of reading the clearance over the radio, the air traffic controller can send it via Data Comm.

List of Cleared Aircraft

This was up in the tower at LAX. On the left are all the aircraft that require voice clearance. On the right are the airplanes using Data Comm. If the black box is filled in, it means that the data link has been connected. You’ll see UPS9904 has an arrow next to it. That means the data is being downloaded by the aircraft. (All the ones above it show a “W” which means that the aircraft has responded with “Wilco” meaning they will comply with the instructions.)

On the UPS 767, it looks like this when the link is connected.

Data Link Established

When the data is downloaded to the aircraft, the clearance can be reviewed in the system. This often will match the data that’s already been sent over by dispatch. That means the pilots can just reply with “Wilco” and be done.

Receiving Clearance

But then let’s say that a change is made. This isn’t uncommon. In that case, the controller can type in the new clearance and send it over to both the aircraft and to the airline’s dispatch straight away, saving all kinds of time that previously would have required the pilots to talk to dispatch.

Adding Revised Clearance

Then the pilots can review the new clearance.

Revised Clearance

Assuming it looks fine, the pilots would then push a button to load the new information into the system. They would also respond with “Wilco” and be good to go.

This speeds things up dramatically and does improve accuracy as well. It’s no wonder the FAA wants to show this off.

[Original air traffic controller photo and texting girl photo via Shutterstock.]


22 comments on “A Demo On How Data Comm Is Going to Make Flying Better

  1. Thanks for including the audio, Brett. Even as clear as those voices were, I can’t imagine trying to write those instructions down as they come across or trying to make a lot of changes to whatever the plane already has in its system. As you mentioned, for international airports where the ATC and the pilots do not share the same native language, and thus may have trouble understanding each other’s accents, this will be huge.

    I’d love to see more posts from you on ATC, including maybe “ATC for dummies” and “Airplane routing for dummies” posts that explain some of the terms mentioned in the audio above.

    1. Kilroy, I retired as a controller after 27 years. Worked at SAT, Washington, Fort Worth and Jacksonville centers and also TMU. If you ever have any questions about anything for me, send me an email, if be glad to answer any questions you have about ATC.

      1. First off, thanks for your service and for doing a job that I am sure I could never do.

        I don’t have your email address (and best not to post it publicly, lest you get massive spam), but as a layperson I find the whole topic of ATC very fascinating. If you have some good detailed articles or books that you could link to or recommend (I’m thinking something along the lines of Air Traffic Control 101, or ATC for Dummies, or even a few chapters explaining ATC to student pilots), I’d be much obliged.

        I don’t know my ATC history very well, but I really like the setup that General Tunner and crew had during the Berlin Airlift, and am always looking for resources on the organizational side (how they planned and organized the materials into West Germany from the States, and how they planned and organized flights from West Germany to West Berlin) of that, as opposed to just books covering the history of the Berlin Airlift and the Chocolate Bomber. I know at the time that was by far the busiest airspace and the busiest airports in the world, but not sure how it compares to the modern day.

        I saw an animation recently that showed the inbound air traffic and weather radar over ATL as a thunderstorm rolled in (https://www.youtube.com/watch?v=eWv4wyy_Jqg), and it was amazing to see how ATC routed planes and changed holding patterns in response to the movement of the storm, shooting planes in to the airport between narrow gaps in the thunderstorm. I can imagine how much of a lifesaver DataComm would be in an IRROPS situation like that.

        1. There are a couple of basic treatments on line http://science.howstuffworks.com/transport/flight/modern/air-traffic-control.htm and (more detailed) http://www.jdtllc.com/ATC%20Basics.htm

          FAA also has a small history office that tracks aviation history, including the history of ATC. That office has over the years published several book length histories of US aviation policy and regulation https://www.faa.gov/about/history/history_pubs/ The current FAA historian is Terry Kraus. She recently published a brief history of ATC in the US. https://www.faa.gov/about/history/milestones/media/Celebrating_75_Years_of_Federal_Air_Traffic_Control.pdf

      2. Randy – If you provided your correct email address when you commented, I can share it with Kilroy if you’d like. Just send me an email at cf@crankyflier.com from that address and I can forward. (That is, assuming you use your correct email as well, Kilroy.)

  2. How much new training is required for the pilots and how have the airlines (generally speaking) planned to ramp up the training component?

    Thanx for the article — it speaks to the #AvGeek side of my brain!

    1. GringoLoco – They made it sound like there wasn’t much training required at all. The pilots are still using the onboard systems they’re familiar with, so it shouldn’t be much. Maybe a pilot can chime in with more details.

  3. Just for the record, the statement that says “all the clearances at the left still require a voice reading” isn’t exactly correct. Those airplanes are still equipped with PDC, or pre-departure clearance. As long as those routes are “as-filed”, which is about 95 percent of the time, the pilot will not have to talk to clearance delivery unless he has a question.

    Data Comm does have promise. But right now, only ten percent or so planes can do it, and that’s not going to change for a while. We were told the cost to retrofit was in the hundred thousands per plane. The RJ’s, including the E’s, aren’t going to be retrofit. SWA has their 800-series equipped, but only half of the 700’s. Delta’s MD88’s, B717, B757’s don’t have it and aren’t going to get it. I haven’t seen any United’s, a few American 737-800’s, and none of the LCC’s It does require pilot and controller training.

    1. Nicole – Interesting. The controllers did NOT make that clear. So with PDC, the controllers never have to read the clearance to the pilot? That would make this far less useful if correct.

      1. Correct. With PDC, the clearance is automatically sent to the airplane. These are generally “canned” flight plans; i.e., DAL123 flies the preferred route every day. Where Data Comm will come in handy is if that route needs to be changed. While the PDC process will still send the standard clearance, someone, whether it’s the airline, the pilot, or traffic management/air traffic control, will put an amended clearance in the system. While the PDC is still sent, it’s not a valid clearance and somehow the pilot will need to contact the clearance delivery controller at the tower. That’s where ATC will have to verbally read the new routing and receive a satisfactory read back. In theory, with Data Comm, the controller will send a new clearance by text so the pilot and dispatcher can read and confirm it without any voice communication. It may cutdown on numerous communications as, at least at the facilty I work at, when thunderstorms move through, certain departure routes and gates open and close every few minutes.

        But on a normal day, where most aircraft fly the same route each day, the benefits are minimal. However, the potential exists down the road. Miami center a few years ago tested a similar system. One of the most beneficial aspects were the simplest tasks. For example, as I am working a sector, I hand dozens of planes off to the next sector. For each plane that enters my airspace, they check on with “DAL123, with you. Flight level 220”. I say “Miami center, roger”. And then after I’m done with them , I hand them off to the next sector. I tell each one to “contact Miami Approach on 126.8”. And then they read it back. However, with Data Comm, I can send these routine transmissions by text. It doesn’t seem like much, but during my 90 minutes on position, if I save 180 transmissions, it’ll let me focus on the stuff that requires extra attention, like reroutes and emergencies, etc…

        1. Nicole – Thanks for all the clarity. It sounds like the focus of the benefit is when speed is most important and there’s a mass impact – thunderstorms. The ability to get the new flight plan sent over and accepted can happen so much faster with Data Comm (or so they’ve explained) and that’s where the most benefit will be. Of course, it’s funny for them to give us this spiel in the tower at LAX, the airport probably least impacted by thunderstorms in the country. But of course, there are plenty of storms enroute that could impact clearance. (Just saw that on flights today heading east because of the build-up.) Then in 2019 when this goes live in the enroute centers, I can imagine it will be even better. The ability to better direct airplanes instantly when cells pop up has to be useful. This all sound right to you?

  4. You would be surprised how hard it is to replace paper strips with an electronic system. This is often mainly related to controllers. They write in pen on the strips. This is hard to simulate via a computer (even with a stylus it just tends to take longer and be clunky).

  5. Only on Cranky Flier do you get this kind of stuff. Thanks.

    Probably a few dorks like myself, non-pilots, who love to listen in, here and there.

    Voices–languages–accents. Amazing how this has worked as well as it has.

    Have you ever listened in to an Air France pilot communicating with ATC in the US (“I know, it’s pretty, but does anyone have a clue what that guy just said?”), or even a Brit. on a British Speedbird (“I know, it’s the King’s English but, say what?”)

    Accents: A real New Yorker; a true-blue Bostonian; a real Cajon from Narlens; someone from Atlanta, or better yet, from Hamlet, North Carolina; a true hillbilly, from all over; someone from the Pennsylvania Dutch area, like from Emmaus, Pa.; etc. Are these people really from the US? And, when they are overseas communicating with a tower or en route control. How do the foreigners get it?

    As to the route, aren’t we at the point where all that’s needed is “Cleared as filed, have a
    pleasant trip!” Or, “Your flight plan as your company filed is fine, at least for the first 10 miles. After that, we’ll tell you where to go. Lot’s of luck!”

  6. When you write ‘Assuming it looks fine, the pilots would then push a button to load the new information into the system.’ do you mean that with one push that cleared route gets loaded into the FMS for the auto flight system? So no more manual FMS programming? That would be sweet. But like previously mentioned not many planes have this capability, not even the new E175s, because yes, who is going to pay to install it in the plane (or pay to choose it as an option when they purchase a new aircraft.)?

    And yes, even on the new regional jets, you see the same green phosphor screen.

    The A380 seems to have more modern electronics including a QWERTY keyboard for easier data entry.

  7. I am an international pilot for a major U.S. carrier and I think I can help with understanding how Data Comm works from the pilot’s perspective.

    In the distant past (from a technology perspective…as in prior to the 1990’s), Instrument Flight Rules (IFR, under which almost all air carrier flights are dispatched) pre-departure route clearances were given to the pilots verbally over the radio. The pilot or dispatcher would request the desired route by filing a flight plan. About 30 minutes prior to their intended departure, the pilots would then call the departure airport’s clearance delivery (or ground controller at smaller airports that didn’t have a CD position) on the radio and ask for their clearance. The pilots would then type that route into their Flight Management Computer (FMC), and depart. In smaller airports, this is still how the clearance delivery process works, and under normal circumstances it works pretty well.

    In the event of disruptions (e.g. a large thunderstorm on the departure path or ATC flow control limits forcing a delayed departure to accommodate arrivals at the destination airport), the CD controller would issue an amended clearance, with either a changed route or a controlled departure time, or both. The crew would then need to adjust the plan they typed into the FMC to match the revised clearance. In some cases, many of the departures from that airport would be receiving amended clearances at the same time because a storm makes the normal departure unavailable for everyone. That means that, rather than “Carrier 705, you are cleared to Kansas City as filed, squawk 1234”, the CD response might be either “Stand by, your clearance is not available yet.” or the CD might have to issue a long route clearance. You might have 20 or 30 flights all trying to get their amended clearances over the single CD radio frequency at once, and each call might take 30 seconds to several minutes, with pilots trying to get their requests in during pauses in the conversations or stepping on each others’ transmissions (requiring both transmissions to be repeated). You can imagine that frequency gets pretty congested and the process becomes very frustrating for pilot and controller alike.

    In the late 70’s, ARINC developed ACARS, the datalink system that allows text transmissions between aircraft and dispatchers, as well as allowing crews to request weather reports and departure clearances. The departure clearance system is called PDC, where the crew sends a request for their departure clearance, and receives a text message with the clearance (or a message that it is not available and instructions to contact CD). That system dramatically reduces the CD frequency congestion, and helps prevent the error where the crew misunderstands or mis-hears the clearance, although they can still mis-read the text or mis-type the clearance in the FMC. It still requires the crew, in the event of delayed clearances, to keep asking for their clearance (over ACARS or voice) until it is finally available.

    What you are calling Data Comm is what I have always heard referred to as DCL, an acronym standing for Departure Clearance via Controller Pilot Datalink Communications (CPDLC). I have used it in PHL and CLT, and I understand it is also active in LAX and soon to be active in MCO as well as other U.S. airports. DCL offers two large benefits to aircrews. First, in the event of a delayed clearance availability, the crew doesn’t have to continually keep asking if their clearance is ready yet. Instead, the way it works is that they electronically notify the CD that they are capable of receiving their clearance via CPDLC. Then, whenever the clearance becomes available, CD sends it to the aircraft, where the crew receives an audio and visual notification. In other words, it is a “push” rather than a “pull” system, again dramatically reducing CD frequency congestion.

    Secondly, when the clearance is sent to the aircraft, the crew can then (after validating it as acceptable), electronically insert it into the FMC. That eliminates the requirement for the crew to manually type the clearance into the FMC (which is a source of errors).

    So, as you can see, the DCL system (which you are calling Data Comm) is a nice enhancement to the historical way in which crews receive their route clearances. It does require costly investments by the carriers in their aircraft, as well as expensive equipment at the clearance delivery position in the control tower. But it does make the CD system work better (at least for crews; I can’t speak for the controller side), and the equipment (CPDLC) is the same equipment that will be used in future U.S. ATC communications inflight, just as it already is used when flying across the Atlantic to and from Europe.

    Hope this helps.

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