NavList:

Howard G
You’ve asked us to do a lot of reading, so I’ve only had time to read the book excerpt and flash through the USNI paper.  I felt happier with the latter. I suspect the author of the former was tilting the lamp a bit.  Unless the gyros had electrically held off brakes, they should kept running for some time.  W.r.t the gimbals wanting to flip at the North Pole, didn’t they have ‘gimbal flip’?   The Heading Reference System (HRS) in the Buccaneer had this for toss bombing.  We had the same equipment as a late mod in the Vulcan in what looked like a biscuit tin balanced on the 7^th seat, but we never tried it upside down.

 I learned ‘grid navigation’ on the Staff Navigator Course and used it on a couple of trips in the Dominie, but like ‘pressure pattern’ you forget it after a couple of months unless you’re using it every day.  Most of the time in the Vulcan we got close enough to see Greenland’s icy mountains but no further north than that, so we never used ‘grid’.

  On 16-17 Sep 1974 when my Aerosystems Course flew to the North Pole in a Britania (XM496), although the passenger cabin was with filled with all sorts of experimental nav-aids for testing, the aircraft's normal Navigator just used standard Arctic navigation techniques for the time: heading (probably gyro in DG mode) checked with astro heading checks, doppler drift and groundspeed, probably grid, and possibly air wave loran fixes for some of the route.  We kept passing him fixes from our gear; whether he used them, I know not.

Would I be correct in thinking that if you can see the Sun, you can check you are at the North Pole within a mile or two, because you have meridian passage conditions 24/7. The Sun’s azimuth is always south and you know you’re at 90N when, after the usual corrections, Alt Sun = Dec Sun?  We must have been there around 16.30 UTC 17Dec74 when Dec Sun would have been about 2° 07'N, so it might have been possible.  DaveP