A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Bob Goethe
Date: 2017 Jun 7, 16:47 -0700
We have talked before about the importance of cross-checking your navigational data, generated by one method, with that generated by a different method. Hence, when sailing you cross-check your GPS with celestial, or if you are near enough to shore, with your hand-bearing compass + radar + depth sounder.
In the words of the NTSB: the pilots were "not using all the instruments at their disposal to determine their location" and landed at Ellsworth Air Force Base, rather than Rapid City, South Dakoka - a mistake of 6 miles.
There is an illustration of the course followed at http://www.bbc.com/news/world-us-canada-40176462