This is some very interesting information you have all provided. Can you explain how you plan step climbs within the NATS? For example, if your flight plan reads thus:
CPT UL9 BURAK/N0465F360 UL9 MALOT DCT 5420N 5430N 5340N 5150N/N0461F380 DENDU CYMON...
how do you know that you will be able to climb to FL380 within the NAT region or at the waypoint? How do you plan ahead for this if ATC can not give you what you request AND how do you know that it will be 5150N that will be ready to climb FL380?
I've always been curious when looking at flight plans how the step climbs are planned. Do they know what the pay load is in advance? Also, does the "5150N/" mean that you climb AFTER 5150N or while you are still travelling to that way point?
Thanks in advance.
Cheers!