Originally Posted by
ksjc
You are adjusting the altimeter QNH setting to compensate for colder than standard temps or am I missing something?
When operating in a colder than standard atmosphere the Honeywell FMS calculates the higher crossing altitudes with the Temp Comp feature. We leave the altimeter setting alone and add altitude accordingly to cross the fixes at a higher indicated altitude which equals the original crossing altitude adjusted for error. The FMS takes the guesswork out of it.
That could be interesting when separating from other traffic that is not using the QFF correction. Expect some queries from ATC on why you are not at the altitude you were cleared to.
Eventually, everyone will move to GPS/GNSS GBAS altimetry as most airport procedures become Vertical RNP and LPV rather than 'baro aided'.