Maastricht CPDLC (and the rest of europe)
Question:
Does anyone know why successfully logging onto Maastricht (EDYY) CPDLC in FANS-1/A(+) equipped B-747 is so inconsistent?
It usually works fine of course on Atlantic and Pacific crossings, fine with Shannon and London, and fine in western China. Yet it seems I am only able to log on successfully with Maastricht about half of the time, which leads to harassment on VHF voice about why we have not logged on (yes I am aware of the requirement to logon if so trained and equipped). If I'm coming from an FIR where CPDLC was not in use I typically begin attempting logons 15 mins prior to the boundary with logon EDYY, the logon will sit in queue for about 10 minutes then come back REJECTED repeatedly. If coming from EGTT for instance the auto transfer to EDYY does not seem to occur and I am left scrambling with rejected manual logons to EDYY at the FIR boundary.
Also I am very unclear on ATL VDN Mode 2 services and FANS B+. I will only assume that the B-747 (even -8) does not have these capabilities and therefore cannot use CPDLC in EDVV/LOVV/LKAA/LHCC/EKDK etc. I have successfully logged on to some of those FIR's in the past, but much like EDYY it seems very inconsistent and random whether the logon will be accepted or not. Of course I am carefully checking that flight number, aircraft registration, etc are all correct.
Thank you for your help.
Thank you for any clarification or reference documents you may be able to provide. My employer provides zero information about this other than the proclamation that our aircraft are FANS-1/A(+) equipped.