Outside the UK you do not know if a descent altitude on the QNH is temperature corrected or not until you check the approach plates/information or by asking the ATC if you are not sure.
One controlled civil airport on our route network does and we know it.
The other is a military airfield which dosn't. When we get a descent clearance they state that the altitude is not temperature corrected. We make a temperature correction and read back "descending to ****ft, temperature corrected".
At uncontrolled airports we make our own corrections.
The ICAO table can be used, or for ease of calculation our SPM states,
"Add 10% to altitude when AD temperature is between -5c to -25c
Add 20% to altitude when AD temperature is between -25c to -40c
Add 30% to altitude when AD temperature is below -40c"
All DA´s and MDA's are corrected as above. As most of our AD's are located at, or close to MSL the correction will only be about 60-80ft for the NDB/DME approaches down to -25c.
Last edited by whitehorse; 14th Nov 2007 at 16:04.
Reason: spelling