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Text Trumps Voice with Data Comm

Feb 10, 2017
Paul Damschen, Manager of Product Management and Flight Operations

We've been seeing a lot of questions here at Universal Avionics regarding Data Comm as more countries roll out new requirements, and as ground systems near completion and become operational. In fact, in terms of complexity, Data Comm is one of the more complex technologies. However, it is easy to use even though the certification and Letters of Authorization (LOA) can be a seemingly endless number of turns. I can tell you that Data Comm is not to be feared; in many cases, it greatly simplifies the antiquated Air Traffic Control (ATC) communication process.

Our Cessna Citation VII is well equipped for Data Comm, as the aircraft is one of our test beds used for system development. As we travel across the country, we use whatever Data Comm services we can as they are available. We've witnessed the rollout of DCL (clearance delivery) services from FAA as the precursor to enroute Controller-Pilot Data Link Communications (CPDLC) operations.

Although I originally didn't really recognize a great need for CPDLC DCL given the nature of our operations at Universal, recent trips around the country have allowed us to take advantage of CPDLC DCL and see its real benefits.

For example, departing from DFW (not a low use airport with the occasional departure), it took us less than 10 seconds to pick up our DCL clearance and acknowledge it, with the clearance itself just being a text message version of the verbal clearance we're all used to. The departure process itself was simpler than our departures out of Tucson, which is fairly typical with multiple controllers and ground personnel to communicate with. The taxi clearance was the most complex element of the trip, taking us across the field with a 25 minute taxi to the active runways.

Upon clearance for takeoff, we had a total of three clearance changes by voice with ATC, 1) cleared for takeoff, climb via the assigned SID, 2) Climb to your final altitude of FL370, and 3) descend via the assigned STAR. That's it, other than a couple of frequency changes. You can expect more of this in the future as we leave voice communications behind.

That's just one example of CPDLC DCL; many of you have heard of CPDLC requirements in Europe as well, formerly known as Link 2000+. Is there a substantial difference? In a word, no – it involves the same equipment, same procedures, same or similar message sets.

How about FANS Oceanic? Well, it has more bits and pieces, but the core communication Data Comm method is still CPDCL, which takes us back to the comments above. Just add some other largely transparent Data Comm elements like Automatic Dependent Surveillance-Contract (ADS-C), and you're a Future Air Navigation System (FANS) 1/A+ qualified airplane. Again, involving the same equipment, same or similar messages, etc.

Any version of our UniLink® Communications Management Unit (CMU) with Software Control Number (SCN) 30.X or later can qualify for domestic CPDLC and FANS Oceanic, with SCN 31.X and later adding European CPDLC capabilities.

We have a lot of materials available to answer your Data Comm questions. Recently, we updated our series of white papers addressing the various topics that we field the most questions on. Data Comm, as the world turns to digital communications in the air, is definitely worthy of its own white paper. You can download a copy here.

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