A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: David Pike
Date: 2018 Jan 9, 01:48 -0800
Gary you asked: just how do you manage to follow a rhumb line while taking that two minute observation in your airplane?
You ask the flying pilot to select a magnetically monitored mode on the compass system. Then, if the system has an Automatic Variation Setting Control Unit (AVSCU), you’ll be flying rhumb lines. I think I’ve mentioned before, the inside of ours looked like a resin cast of the inside of somebody’s ear rotating with longitude with a little pecker working against it moving in and out with latitude*. If you don’t have an AVSCU, then you probably have to apply a further correction for change in variation. As the song says, “Corrections, there are a few, but then again, ……..”. DaveP
* There was always the danger of an AVSCU run-away, which was another reason for regular heading checks againt the Pilot's E2 Compasses or celestial.