5 ms·

Reminds me of the story of the Nautilus, where upon reaching magnetic north, and discovering every direction from there was therefore South, the navigation comp

Reminds me of the story of the Nautilus, where upon reaching magnetic north, and discovering every direction from there was therefore South, the navigation computer folded.

eesmith 5y ago
I thought that was interesting, looked for more details, and found https://www.usni.org/magazines/proceedings/1958/december/navigating-under-north-pole-icecap https://www.usni.org/magazines/proceedings/1958/december/nav... saying almost the opposite: > The [magnetic] compass did operate as well as was expected. Even though at times the deviation was high, its readings were constantly monitored, especially after crossing the Pole, for a change in deviation indicating a course error. No such error was found, but it remains a fact that a good magnetic compass even though readings are approximate and/or relative is still essential to navigation in Polar regions as a basic backup should all other equipment fail simultaneously. ... > The fact that a northseeking [gyro]compass did take the ship to a point 60–100 miles from the Pole and at that point would have by itself provided information to take the ship within normal navigational accuracy of the Pole may seem amazing to outsiders. We aboard, however, expected this type of performance from the MK 19 as a result of our previous Arctic experience with the compass and its everyday reliability since then. Even though it had already outperformed the expectations of many, it still failed to show any readable drift rate and was an outstanding DG. ... Now, that concerned the North Pole, not Magnetic North Pole, but 1) they had a gyrocompass too, with cross-checks for possible failures, and 2) there's no mention of a navigation computer - it appears the calculations were done manually.
- ncmncm 5y ago
  The North magnetic pole has never in living memory been especially close to the actual pole. At that time it was on land, as it is now. So, you can't drive over the North magnetic pole in a submarine, though there have been periods when you could. At and near the pole, the direction is mostly "down". Recently a Boeing 747 flying over the North Pole had all four engines die in the same moment. You may guess things were pretty tense in the cockpit for a while. After it glided below 10,000 ft altitude, they managed to fire them up again. There was a particular combination of pressure, temperature, humidity, and history the designers had thought would never happen. The engine manufacturer figured out what had happened and reprogrammed the engines (on all 747s) so it would not happen again.
  - eesmith 5y ago
    Before posting I had checked the location of the North Magnetic Pole, since I remembered it being in over (under?) land, in high Canadian latitudes. https://en.wikipedia.org/wiki/North_magnetic_pole https://en.wikipedia.org/wiki/North_magnetic_pole and more specifically the chart at https://en.wikipedia.org/wiki/North_magnetic_pole#/media/File:North_Magnetic_Poles.svg https://en.wikipedia.org/wiki/North_magnetic_pole#/media/Fil... show it is indeed 1) over water, 2) near the North Pole, near 86.400°N 156.786°E, and 3) close to where the Nautilus It is the North Geomagnetic Pole which is over land. Since nickdothutton said "magnetic north", I took it to be plausible. HOWEVER! I was wrong, because I didn't check far enough. The geographical location of the Earth's North Magnetic Pole moves, and in the 1950s it was in the Parry Channel of the Northwest Passage. Which is not where the Nautilus went. Do you have a reference for the 747 failure? I couldn't find one. In October 1977, Pan Am Flight 50, using a 747SP, circumnavigated the Earth via the poles: San Francisco over the North Pole to London, then Cape Town, then over the South Pole, then Auckland, then back to San Francisco. With no engine problems. While your description reminds me of BA flight 009 going through a volcanic cloud, where all four engines flamed out and they didn't get a restart until about 12000 feet - https://en.wikipedia.org/wiki/British_Airways_Flight_009 https://en.wikipedia.org/wiki/British_Airways_Flight_009 .
    - ncmncm 5y ago
      I am trying to find the 747 polar engine failure. As I recall, it was a cargo flight, the which attract less attention from aviation archivers.
      - jacquesm 5y ago
        AVHerald should have it though.

Reminds me of the story of the Nautilus, where upon reaching magnetic north, and discovering every direction from there was therefore South, the navigation computer folded.

eesmith 5y ago

I thought that was interesting, looked for more details, and found https://www.usni.org/magazines/proceedings/1958/december/navigating-under-north-pole-icecap https://www.usni.org/magazines/proceedings/1958/december/nav... saying almost the opposite: > The [magnetic] compass did operate as well as was expected. Even though at times the deviation was high, its readings were constantly monitored, especially after crossing the Pole, for a change in deviation indicating a course error. No such error was found, but it remains a fact that a good magnetic compass even though readings are approximate and/or relative is still essential to navigation in Polar regions as a basic backup should all other equipment fail simultaneously. ... > The fact that a northseeking [gyro]compass did take the ship to a point 60–100 miles from the Pole and at that point would have by itself provided information to take the ship within normal navigational accuracy of the Pole may seem amazing to outsiders. We aboard, however, expected this type of performance from the MK 19 as a result of our previous Arctic experience with the compass and its everyday reliability since then. Even though it had already outperformed the expectations of many, it still failed to show any readable drift rate and was an outstanding DG. ... Now, that concerned the North Pole, not Magnetic North Pole, but 1) they had a gyrocompass too, with cross-checks for possible failures, and 2) there's no mention of a navigation computer - it appears the calculations were done manually.

ncmncm 5y ago
The North magnetic pole has never in living memory been especially close to the actual pole. At that time it was on land, as it is now. So, you can't drive over the North magnetic pole in a submarine, though there have been periods when you could. At and near the pole, the direction is mostly "down". Recently a Boeing 747 flying over the North Pole had all four engines die in the same moment. You may guess things were pretty tense in the cockpit for a while. After it glided below 10,000 ft altitude, they managed to fire them up again. There was a particular combination of pressure, temperature, humidity, and history the designers had thought would never happen. The engine manufacturer figured out what had happened and reprogrammed the engines (on all 747s) so it would not happen again.
- eesmith 5y ago
  Before posting I had checked the location of the North Magnetic Pole, since I remembered it being in over (under?) land, in high Canadian latitudes. https://en.wikipedia.org/wiki/North_magnetic_pole https://en.wikipedia.org/wiki/North_magnetic_pole and more specifically the chart at https://en.wikipedia.org/wiki/North_magnetic_pole#/media/File:North_Magnetic_Poles.svg https://en.wikipedia.org/wiki/North_magnetic_pole#/media/Fil... show it is indeed 1) over water, 2) near the North Pole, near 86.400°N 156.786°E, and 3) close to where the Nautilus It is the North Geomagnetic Pole which is over land. Since nickdothutton said "magnetic north", I took it to be plausible. HOWEVER! I was wrong, because I didn't check far enough. The geographical location of the Earth's North Magnetic Pole moves, and in the 1950s it was in the Parry Channel of the Northwest Passage. Which is not where the Nautilus went. Do you have a reference for the 747 failure? I couldn't find one. In October 1977, Pan Am Flight 50, using a 747SP, circumnavigated the Earth via the poles: San Francisco over the North Pole to London, then Cape Town, then over the South Pole, then Auckland, then back to San Francisco. With no engine problems. While your description reminds me of BA flight 009 going through a volcanic cloud, where all four engines flamed out and they didn't get a restart until about 12000 feet - https://en.wikipedia.org/wiki/British_Airways_Flight_009 https://en.wikipedia.org/wiki/British_Airways_Flight_009 .
  - ncmncm 5y ago
    I am trying to find the 747 polar engine failure. As I recall, it was a cargo flight, the which attract less attention from aviation archivers.
    - jacquesm 5y ago
      AVHerald should have it though.