Does enybody know, what will be the practical usage of CPDLC in EuroControl area where you have so many FIRs and dense traffic with good radar coverage. Maybe for high level overflights. CPDLC is much slower comparing to voice requests for FLCH or WX avoidance or rerouting....You have to type yor request, than wait for the answer then execute...sometimes it take 10 minutes to get the approval, to climb 2000 Ft or deviate 20 deg to the right. That is why all those FIRs established special procedures for WX avoidance or flight path deviations in case of emergency, without received clearance
CPDLC over India, Pacific, Atlantic regions etc. is very usefull since there is no radar coverage and HF comm is the only way of communicating.
Rgds
L.