Boscombes XX367 used to do polar flights once a year for students on a specialist course at Cranwell if i remember rightly, up to the early eighties when she was disposed of. Must be someone on here who remembers the detail and the NAV kit used ??
I flew XM 496 on one of those polar flights in August 1971, which is the Britannia now preserved at Kemble. The Spec N course was held at the College of Air Warfare, RAF Manby in those days. We were overrun by navigators, sixteen in all I seem to remember, including two of my own as we were going to use grid and gyro. The front of the cabin was fitted out with tables to take the extra navigation equipment, consisting of several Loran sets and two INS units, all connected to the front galley by a patchwork of cables. One (Marconi I think) INS came from Farnborough and was normally used to record data during Harrier test flights. It was unsuitable for navigation and caused a lot of head scratching in the northern latitudes. The second INS was made by Litton, accompanied by a company rep who was working his way through a pile of Playboy magazines every time I went back! The Litton worked flawlessly. We flew from Brize Norton to Thule on day one (9h.10m). On day two we headed north along 70 west and circled the North Pole at FL200 for about 30 mins while readings were recorded before setting course for the Outer Hebrides, which also turned out to be TOD for BZN from our cruising height of FL370! Flight time was 11h 25m. After all the data had been analysed it was reassuring to learn that the Smiths Flight System compass performed extremely well, having been checked and recorded by the operating crew every 20 minutes between Thule and the North Pole. It was a long time ago so more details have slipped my memory.
In September 1973 I flew a Britannia from Quebec to Resolute Bay where the Smiths Flight System proved to be somewhat confusing. At that time the magnetic north pole was just 80nm from RB, resulting in almost 90 degrees of variation. During an ILS approach to land on the northerly runway the glide slope was horizontal (where the localised should have been and visa versa). Low cloud, variable decision heights due to passing icebergs and the prospect of landing on a rough gravel runway were not conducive to a relaxed flight deck! Next day the flight to Yellowknife was like a walk in the park.
XM496 at Thule. The dome housing the doppler radar can be seen under the fuselage between the main landing gear.
Resolute Bay shortly before departure.
