After two days of reading this topic I have realized finally!
By the way I would like to ask:
“…maintain five thousand, expect flight level 310 one-zero minutes after departure…
this is not the first time to see such type of route clearance. we have a lot of discussion over here regarding route clearances and I would like to know if it is some special FAA rule or wrong interpretation of ICAO rules.
I prefer and I may bet that it is correct to say:
XZW clear to.. follow.. climb to 6000(TWR)
APP: XZW identified clear to.. climb to 140
ACC: XZW identified clear to.. climb to 310
For me it sounds too risky to give clearance on FAA way,because it could happen that a/c wouldn't be able to climb safely to fl310 in ten minutes. It is not big problem if r/t works properly but what happen and how you deal in cases of two way radio communication failure.
I know that this is out of topic absolutely but text inspired me in that direction.
I will appreciate reasonable answers.