CPDLC… Controller Pilot Digital Link Communications. It all started when experts predicted that with the increasing demand, congestion on the air traffic control frequencies will make communications impossible and hence a cap will have to be put on the number of aircraft being served simultaneously, severely restricting ATC capacity.
CPDLC is in fact non-verbal communications using predetermined messages for all but the most time critical exchanges. A kind of SMS service for aviation if you like.
A decade or so ago, Europe was actually leading the world in developing CPDLC, so much so, that American Airlines, disenchanted with the FAA performance on the same subject, asked to be allowed into the EUROCONTROL Petal trials, the trendsetting project that solidified the basis for this new communications technology.
Both the US NextGen and the European SESAR projects show digital link communications as one of the most important elements of the new ATM system. However, some of the main European provider states have disclosed at the end of 2012 that, in spite of a mandate by the European Commission, they will be late with their digital link implementation. One of them will not be ready until 2019!
Of course to-day we know a good deal more about the future ATM system than we did back in the days of Petal. Back then, the focus was mainly on avoiding communications congestion in continental airspace. Anything more that digital link could do was still just a glimmer in the eyes of the most daring dreamers amongst us.
In the meantime, we have of course defined the meaning and practical aspects of Trajectory Based Operations, the new concept which finally does away with the legacy airspace based concept to replace is with something that is able to give back most of the freedom to airspace users that was taken away when positive control was introduced. In the drive for ever more economies in operations, that freedom translates to many millions of bucks saved every year for every company.
Although the technology for CPDLC is mature and proven, there are of course minor issues that still need to be resolved. It is yesterday and to-day that those issues should have been addressed, the system shaken down and made ready to take the next step… to be the essential enabler for Trajectory Based Operations.
There is another aspect of to-day’s reality that will spell trouble in the near future. Namely, the discussion raging on whether or not a digital link system that is not integrated with the aircraft avionics is worth pursuing at all. Had digital link been introduced when it was first planned, such a discussion would not be taking place now… We would be planning how to evolve towards TBO.
Of course air/ground digital link used to ease voice communications congestion would have been/will be just a first step. Important and useful as it is, the real potential of air/ground digital link will be unlocked when the long and complex clearances involved in TBO do not need to be sent via voice… a task impossible anyway.
Non-integrated data link technology is nonsense because it creates a workload imbalance. Everyone recognizes that it is not possible for the air traffic controller to pass TBO type clearances via voice and hence digital link is required. But if the same complex clearance arrives in the cockpit and someone has to enter it into the FMS manually, the whole concept falls on its face.
Those who have delayed the implementation of air/ground digital link, thinking it was not urgent, have apparently not thought through what their actions will precipitate. Here we are now, instead of graduating from high school debating whether we should go to kindergarten. Once again parochial thinking has proven to be effective… it pulled out the most important enabler from under Trajectory Based Operations.
Will we never learn?