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Wind speeds on the MCDU

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Hello,having the MS real weather, updating every 15min, I noticed some strange wind speed readings on the MCDU during the taking off phace from EDDF. Selecting the PROG page I get a wind speed reading of 297/050 and on the F-PLN page I get TAIL/007. What is wrong, I thought these numbers should be identical. Well, at least the identical. The problem (?) doesn't stop here. During cruising on the PROG is see 300/150!!! and on the F-PLN TAIL/015. Is there something that Im missing?Thank you


Panos Kotzias

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Definitely something you're missing here:It all depends on the direction you're headed...If I'm going 270 and the wind is 270/15, then I have a 15 knot headwind. If I'm going 360 and the wind is 270/15, I have a 0 knot headwind. If I'm going 090 and the wind is 270/15, then I have a 15 knot tailwind.If the wind is 270 at 100 and I'm flying heading 359, I still only have a 1.7 knot headwind. The HEAD/TAIL function only considers the wind that is purely affecting my forward speed. That's it.Here's a quick calculator, if you're interested:http://www.aeroplanner.com/calculators/avcalcdrift.cfm


Kyle Rodgers

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Hello KyleSo if I understood well, the actual wind speed reading is on the PROG page. If yes, then another question arises. During descending I noticed that the value was 300/100 and immediately dropped to 300/17 and then again back to 300/100. Is this normal?Thank you for the link it was quite helpful


Panos Kotzias

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You're welcome.What you describe (300/100 then /107 and back to /100) is normal, in FS at least. Flying real world, it normally smoothly dies down as you descend. There are exceptions (large changes in wind speed and direction are what cause wind shear and turbulence), so you would also see it RW as well. It's just more often seen in the sim, as the weather engine is particularly weak.


Kyle Rodgers

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