Bob Moore wrote:
Andrew Sarangan wrote
So, I still don't agree that navigation systems have
advanced to the point where we can abandon the
magnetic based instruments.

Hmmmm....I wonder how we used to navigate 'over-the-pole'
back before INS? Hint....Grid Navigation, an unslaved
DG referenced to true north.

Bob Moore

Way back when I was a navigator on a KC-135 using Grid Navigation we
referenced the DG to Grid North, not True North. Big difference between
the two, although I think I know what you're hinting at.

And, I remember taking a celestial shot every 15-30 minutes or so to
check for gyro precession. That would be hard to do in the Warrior I'm
flying nowadays. :)

--Walt Weaver
Bozeman, Montana