It is not just 40 years since the first manned flight to the moon, but also the advent of commercial INS or inertial navigation systems in scheduled airline service.
http://video.google.com/videoplay?docid=-3315357880028856913To complete the process of certification in 1969 however a passenger carrying flight had to be made, and Pan American World Airways decided to ‘divert’ a London-Seattle service in a Boeing 707 to go directly over the North Pole, to which it had already made other non-revenue navigational test flights.
Although not mentioned in the historical video, this added around one hour to the trip time, which would normally fly a shorter route across northern Greenland and then into the Canadian arctic.
No exact date has come to light for the actual flight, but there is a cameo view of the 15 minute long ‘night’ that occurred as the jet was on its way to 90 degrees north.
This would be consistent with a flight around this time of year in the arctic latitudes, but not in the sequence shown in the video edit, as the expanses closer to the north pole would be in unbroken daylight.
The video is also of historic value in capturing the use of a four man crew on the Boeing 707, the captain and first officer, plus a flight engineer and more unusually, a navigator, whose role was of course to be completely eliminated by INS.
In the world of air transport the art of celestial navigation, plotting the angular position of the sun or bright stars at a particular moment in time to determine a plot on a map, was one that passed into history with the last of the long range piston engined airliners like the Douglas DC-7C and the ultimate version of the Lockheed Super Constellations.
Passenger flights without INS over or very near the north pole began in 1954, but mostly tracked well south of it. Today, thousands of people fly effortlessly across or near the north pole every 24 hours,far above a frozen ocean that is now thinner in ice coverage and more fractured than it has been for the most part since the incredibly mild spell that was recorded in late 1939 and through the summer of 1940.
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Most B707 were fitted with a “polar-path” compass, incorrect use of same resulted in some very “interesting” navigational errors in high latitudes. Use of “grid” navigation and/or polar gnomic charts were ( in my experience) best left to specialist navigators.
A very well kept secret for many years after, but the first “inertial” navigators saw the light of day in B-29 lead bomber aircraft in the Pacific in late 1944 or early 1945. As I recall, this resulted in the first direct measurement of the strength (or even existence) of jetstreams.
Thanks for the interesting and historical video Ben. The INS is a piece of technology unknown to most people but they have been arguably the most important piece of equipment for en-route navigation available for many decades, and remain an integral part of the flight management system. It also was and still is also used in ships, where it is called SINS. All derived from military technologies of course. It’s independence from satellite-based systems is an enduring advantage. Punching incorrect waypoints into the INS however can lead to interesting developments. I once observed on radar a British Airways B747 flying Melbourne – Sydney turn right 90°and fly out over the NSW south coast. Being night time, the crew were completely oblivious (and probably enjoying their flight deck dinners) until alerted by ATC. The BA captain sheepishly offered the ‘mis-punched waypoints’ excuse before requesting a vector to Sydney.
Ben,
Circa 1979 Trans Australia Airlines still used a navigator on their Perth to Cocos Island run in the Boeing 727.
As a F/O I was shown the star plots by the navigator, Ted Allen. He allowed a small known error to run to around mid way, and then made a track correction, rather than to make numerous corrections along the way. The plotted position was interesting as at 450 knots the distance travelled in the time between star shots made the exact plot close but not perfect. The Cocos NDB came in at a long distance out, for the tracking closer in.
TAA fitted the 727′s with INS a short time later as I remember.
Just did my first northern polar flight three days ago. Didn’t realize it was close to any significant date. Didn’t see Sir Hubert Wilikins ashes though.