|  |  | | B777 - prelet v blizkosti severneho polu 2. 2. 2014 / 16:38 | |
| | Prosim, urcite ste uz niekto letel cez severny pol resp. v jeho blizkosti.
Ja to letim prave teraz z OMDB do KLAX.
Na ND sa mi objavil napis "GRID 285"... Pri pisani prispevku uz je 287.
Co to znamena ? Manual mlci  Mam cakat zrutenie "Matrixu" ? 
Diky za vysvetlenie |
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 |  | | | B777 - prelet v blizkosti severneho polu 2. 2. 2014 / 17:02 | |
| | | Nemáš FS9? tam byl s pohybem blízko pólů problém. |
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 |  | | | | B777 - prelet v blizkosti severneho polu 2. 2. 2014 / 17:05 | |
| | Mam ten simulator "ktorehomenosanesmievyslovit"
Ale mne ide o vyznam tej indikacie, s preletom nad polom problem neni
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| | | | | | B777 - prelet v blizkosti severneho polu 2. 2. 2014 / 17:23 | |
| | | přepni kompas z MAG na TRUE a řekni, jestli to zmizelo |
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| | | | | | | B777 - prelet v blizkosti severneho polu 2. 2. 2014 / 17:42 | |
| | | Nezmizlo, lebo uz som mal zapnuty TRU .... je to vidiet aj na obrazku. |
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| | | | | | | | B777 - prelet v blizkosti severneho polu 2. 2. 2014 / 17:53 | |
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| | | | | | | | | B777 - prelet v blizkosti severneho polu 2. 2. 2014 / 18:19 | |
| | Nie som tam registrovany a neregistrovanych to prijme iba 250 a doteraz sa na mna nedostal rad.
Nemozes to sem postnut alebo proste vysvetlit o co ide ?
Jedine com som po vlastnej linii vypatral, ze toto sa zobrazuje ak prekrocim 82.stupen severne alebo juzne
Diky.
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| | | | | | |  | | | B777 - prelet v blizkosti severneho polu 2. 2. 2014 / 19:10 | |
| | Ono je to dlouhý, jsem línej to překládat:
Příspěvek1:
GRID 237 indicates that the airplane is navigating with reference to true/grid north, and is trying to fly a course of 237 degrees true.
My only knowledge is from the B744.....
The heading reference switch permits selection of a magnetic north (MAG) or a true north (TRU) reference for the navigation systems. The switch can be positioned to either TRUE or NORM. If NORM is selected, the system automatically determines the reference as follows:
The reference is TRU when the airplane is north of 73 degrees north latitude or south of 60 degrees south latitude, otherwise the reference is MAG.
When the reference is TRU, there are no AFDS roll modes other than LNAV available. When the reference changes from MAG to TRU with the HDG SEL mode engaged, the AFDS automatically changes to HDG HOLD.
Příspěvek2:
Picture, if you will, a polar stereographic projection of the polar region (the projection you'd get if you stuck a light bulb at the centre of a hollow, semi-transparent globe, and projected onto a flat sheet of paper that touched the earth at the pole, and was perpendicular to the surface at that point). So the meridians are straight lines, fanning out in a circular way from the middle of the page (the pole), and the parallels of latitude are concentric circles.
Now great circles are, to a close approximation, straight lines on a polar stereographic, so you draw your intended great-circle track on the chart, and unless you happen to be heading due north or due south, you're going to find your true direction is going to change a lot as you continue along the line. That's convergence, and it's a big problem near the poles where it's very large, becoming smaller and smaller as you move towards the equator.
So align your DI to North, fly a little way (you're near the pole, so you'll soon cover a good few degrees of longitude) and all of a sudden, your DI no longer points North - it continues pointing to the space direction that you aligned it to, but Earth North has shifted beneath you.
That's not even all though, since the magnetic variation would also be changing a lot near the poles, so all in all you'd be lost pretty rapidly.
Nowadays, you'd use GPS or INS. Convergence wouldn't be a problem, and nor would magnetic variation.
In days of yore, for polar flying, a "gyro north" was arbitrarily chosen, and a grid of straight lines was overlaid over the chart. Say gyro north was chosen to be equal to true north at 20E. You could then fly a grid heading which would not change along your straight line drawn on the chart.
Along the 20E meridian in our example, grid track and true track would be the same - everywhere else, the two would differ.
You'd use various voodoo to convert back and forth from grid to true, so as to relate your grid position to your true position, since the grid position/track/heading is, as I said, arbitrary and means nothing to anyone else such as ATC. It's just a practical way to actually accomplish the navigation in the air, since it eliminates using a reference (True North) which is changing rapidly. Instead, a reference that doesn't change has been arbitrarily chosen.
Now if you can find me a commercial pilot (or at least one who doesn't actively fly in polar regions) who can remember what grivation (or indeed an isogriv) is without looking it up, I'll eat my hat. |
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| | | | B777 - prelet v blizkosti severneho polu 2. 2. 2014 / 20:02 | |
| | Sice ti neporadím, ale ten tvůj longhaul už sleduju delší dobu na GoogleEarth (CVARS) a držím palce, ať nezklame technika, to je teda VÝLET panečku  |
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| | | | | B777 - prelet v blizkosti severneho polu 2. 2. 2014 / 20:05 | |
| | Diky, aspon mam dokaz, keby zlyhal tracker IVAO
Ja to 3.LEG nasej slovenskej LH tury
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| | | | B777 - prelet v blizkosti severneho polu 22. 2. 2014 / 22:09 | |
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| | | | | B777 - prelet v blizkosti severneho polu 23. 2. 2014 / 07:57 | |
| | | Pěkné - dík |
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| | | | | B777 - prelet v blizkosti severneho polu 24. 2. 2014 / 08:09 | |
| | Tý jo!
Dobrý čtení, akorát je toho na celou zimu !
(Nemyslím ten pérvní příspěvek, ale tu knihovnu ve druhým odkazu).
Ale je to krásně napsaný, čte se to jak pohádka na dobou noc...
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1x 
