"RomeoMike" wrote in message
...


Peter Dohm wrote:

In view of my recollections of ground school, I believe that it might be
least confusing to continue using the term deviation for the instrument
error as installed, variation for the difference between true and
magnetic
north, and inclination for the angle between the lines of force and the
horizontal--leaving the term declination unused.

Peter
(Planning to think about this at leisure)



I suppose that the term declination would better be unused in favor of
"variation" in the context of defining the difference between magnetic
and true north, and in my experience it is unused in aviation.
Unfortunately, it is used on government issued topo maps and in some
orienteering books and by some orienteering compass makers, who tell one
to enter the "declination" into the compass card so that the needle
points to true north. Inclination is another term with different meaning
in different contexts.

I'm comfortable with "variation" because that's what I learned, but believe
that you are probably right.

BTW, you sent me to the dictionary for "orienteering"

Peter