The clash of VDL Mode 4 and VDL Mode 2
Following many years of testing and discussions on numerous forums, VDL Mode 2 was proving itself to be the answer that, combined with ATN protocol, could offer the initial implementation of Controller Pilot Digital Link Communications. There is little else it would do however it were built with a appealing factor over anything else. There is agreement it would have the desired effect! Many people tended to think about this virtue to be of little value however it had been as essential as the link’s capability to perform. Achieving consensus around the scale required to choose which connect to me is a legendary hurdle so when agreement can there be, it shouldn’t be placed at risk.
But that’s precisely what had been made by the promoters of some other technology which goes as VDL Mode 4. VDL Mode 4 can perform everything, they claimed… It will voice, texts as well as ADS-B! The majority of the claims were obviously true and also the initial hiccups using the system weren’t any need to discard it. Yet it never managed to get in to the mainstream and also the hard push did just one factor: delayed the inevitable, the ultimate agreement on Mode 2. VDL Mode 4 lacked the most crucial element: industry deal for implementation.
Mode 4 does service inside a couple of places and in ways it represents a lost chance. If rather of using the easy (=cheap) way to avoid it, the EUR RAN had required a brand new system rather of 8.33 kHz, VDL Mode 4 or perhaps an enhanced form of it, might perfectly have went to the very best. Because it was, it grew to become an annoyance for many, a hurdle for other people, however it most definitely didn’t end up being the major new aspect in ATM technology it might have deserved.
Once the USA also agreed they would use VDL Mode 2 and ATN for CPDLC, the conga line was prepared to transfer to the large league.
The trendsetting PETAL trials
EUROCONTROL in just a minute of poetic inspiration gave the name PETAL for their early (as well as in Petal II the later) air/ground digital link trials. PETAL is really a phrase also it means Preliminary EUROCONTROL Trials of Air/ground Datalink.
It’s not an exaggeration to state that without PETAL we will not have air/ground digital link the way you realize it. The work defined the operational concept, the messages, labored around the technical enablers as well as in general acted like a motor of digital link development.
You might have observed that i’m while using term “digital” instead of “data” within my references to digital link. Initially, the “d” was indeed for data but following lots of discussion and misunderstandings around such things as digital voice and knowledge, it had been made the decision to make use of the term digital instead of data because it expresses the essence from the link which carries data however the data could be the representation of analogue voice or digital messages… you receive my drift? And exactly why there have been a lot of misunderstandings?