Originally Posted by
ScepticalOptomist
On the routes I fly the only ATC unit asking for that is NZZO.
Does anyone know why?
This is what I got from our FANS manual :
Transmission times for messages may vary for a number of reasons including the type of transmission media, network loading, or the criteria for transitioning from one media to another (e.g. VHF/Satcom). Operational response times may vary depending on workload and complexity of the instruction or clearance.