how to calculate a ta / tl
 

hi pilots,

can u please help me on how to calculate a tl basing on a ta of 5000 ft?

pls give example for qnh below / above isa. what was again the buffer they asume in atc for the transition level calculation? 500 ft or 1000ft btwn. 2 fl´s?

yours lusthansa

Transition Level is either:
Nominated and published to the plates
or
Selected by ATC on the day

It is not calculated

Ah Just reread your post
Excuse the misunderstaning. You are asking about the TRANSITION LAYER

In that case convert the TA to that based on a pressure setting of 1013. You then have the difference between the two, or transition layer.

At the out set I doubt if this system is still current.learnt it about 20 yrs ago,:confused: never the less here goes
T/A:is 1000' above the highest obst within 25nm radius of the stn rounded off to the next higher 1000.
T/L: is 1500' above t/a when stn QNH is <1013.2
is 1000' above t/a when stn QNH is>1013.2
Some countries have standardised TA to be a common figure that covers all arpts.

Transition level changeover
 

If the transition level is listed as "By ATC", in the descent, should you change at the controller's first clearance to an altitude or should you change at the transition altitude. This has been a re-occurring question among crew members and to date, I have not read anywhere with a definitive answers. Maybe some of the ATC types can help