We took a Jaguar to Nellis in in 1974 for "hot and dry" trials. Took two Victors to get it there and we were very grateful for the Jag's INS when crossing the pond
You remind me of when I was controlling a RWR trial between a Jag and an F4 in the same period. The trial required a 200nm 180 intercept with zero displacement.
The intercept was set up about 4 times but the displacement kept drifting out until, at the suggestion of one of ex-Nav(?) controllers, I asked the Jag pilot if he was flying True or Magnetic?
There was a prolonged pause until the pilot sheepishly replied, "I'm not sure really, I'm just flying along the line on the INS".