Phraseology 1.0
Dear pilots,
I have noticed in my day to day operation some "changes" that may interfere ( significantly) with safety ( direct ) of our operations.
example ,
ATCO:triple X, climb to FL 170 report passing 6000
pilot: passing 6000
ATCO: ???
It is not one crew, one company or one CAA (that approves training centers ) .It seems that such answer became standard.
So if it is standard , please tell us ICAO document that you refer in such circumstances, We will accept it and change our knowledge and expectations.
or if there is no such document, please refer to
DOC 4444 ATM/501 Procedures for ANS Chapter 4.5.7.5 READBACK OF ATC CLEARANCES and Chapter 12 PHRASEOLOGIES
Also, DOC 9432 MANUAL OF RADIOTELEPHONY with the special emphasis to given question- read back of level instruction
Chapter 3 3.3 Level instruction
as you could see in those pages example,
G-AB report passing FL 80
G-AB WILCO
G-AB PASSING FL 80
and that is point , you may answer with WILCO ( although it is a little bit contrary to read back instructions ) but you can not answer with passing before actually passing that assigned ( or otherwise restricted ) level.
It is not safe, it is not under international standard, and may confuse ATCOs ( rare- because we know that you aren't Spaceshuttle so can't climb 10 000 feet in a second ) but other pilots -very often and it is real danger.
It is not only restricted to level instructions but to other instruction and read back procedures as well, so stick it to rules and common sense, and World will be better place at the end of the day.