well he is using QFE isn't he? station level pressure? right?
So if his Altimeter is showing 10,000', then he is 10,000 above the station, which is 2,500' above MSL. So without taking the cold temp into account isn't he 12,500 above MSL.
From the Cathay manual: "published procedural altitudes, including MSA's, should be corrected using the table below"
ISA add 0%
<ISA-15 add 10%
<ISA-30 add 20%
The temp at 12,500' should be about -10c, so we have a deviation of ISA-10
Therefore take 0% off 12,500' and he is close to 12,500' above MSL.
Also don't forget when we say "altitude" we generally mean above MSL
When we want to talk about above the ground we say "height"
Another clue.
Last edited by ACMS; 21st Sep 2007 at 16:00.