Transition level by ATC
 

Had a discussion last week with my Captain.

TL by ATC. So set Qnh when told to descent to an altitude?

Very confused!

Thank you.

Sorry have missed something here, why are you confused? If you are operating in UK controlled airspace you will be given the QNH when you are given descent instructions which go through the transition level. No need to worry about what the current transition level is, we controllers get paid for taking this worry away from you!

<<ATC will calculate the appropriate TL and tell the pilots, or put it on the ATIS or whatever.>>

I guess that's something else new since I retired?

If and when I give an altitude and QNH I expect you to use this and not 1013,2. There´s usually a reason for this. In our sectors we have an instrument approach that starts at 6000ft QNH. We clear arrivals to another nearby airport to 7000ft QNH (the same one of course) instead of FL70 at pressures of 1013 or below to a) get these guys down on profile and b) give the QNH at a convenient time. We also have special flights like photo missions flying on local QNH that require other (descending) traffic setting local QNH as well to provide separation.

Where does your transition layer occur, what altitude on the way up and what Flight Level on the way down?

Where I am the highest cruise altitude is 13,000' and the lowest FL is 150. So on the way up 1013 is set above 13,000 and area QNH set below FL 150. No cruising between 13,000 and FL 150.

TL in Germany is normally FL60 or FL70, depending on QNH. I´ve seen TL FL80 only once in fifteen years.
We use every available level in the TMA, therefore use QNH or 1013,2 as needed.

Once leaving your flightlevel to the cleared altitude you can change your altimetersetting, you don't have to wait until passing TRL.

But I don't think the rule applies when climbing, only descending.

If your cleared level immediately after departure was a Flight Level, would you take off with 1013 set?