I must admit this has been fun. I did not want to stir anybody up, but was simply pointing out that according to the airplane and systems manuals I have studied, there is a temperature correction applied to those airplanes using the CADC/ADIRU system and that therefore so far as I can see, the Altimeter reads True. Why else would temperature be an input to the altitude computer?
I freely admit that my opinion might be wrong, and would like to read something from someone who does know the systems.
The stuff about exactly how to correct the altimeter is very interesting, and for many airplanes will be necessary. But it MAY not be necessary for the airplanes under discussion here, and therefore MAY be irrelevant. The Authorities would expect you to know if it applies to your equipment or not.
It may be of interest that in discussing this with a B777 colleague, he is of the opinion that his altimeter is in fact not corrected, since he has seen errors at the OM he did not previously see in the B747-400.
I would love to discuss this with Boeing, but they have a policy of not talking to a pilot directly.
This forum is not for the technical education of the reader, since nobody's credentials can be checked. I see it as food for thought, and cannot understand why it elicits such a furious, strident response from some.
Maybe a form of road rage?