Originally published I believe in a BA Staff magazine...
The Flt. Ops. one of course,tho' I confess I can't remember the title at the time.
being involved in early INS trials - the first was bolted to the side of a 707 freighter just inside the main freight door and was about the size of the side of my house - the article was invaluable to me !
I remember firing the thing up in the Central Area of LHR, and when we got to the threshold of 10 R ( now 09 R ) I was totally amazed to see that it had recorded that we had moved 1 nm West and 0.5 nm South.
Shades of things to come.