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Guest fly7

Winds enroute

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Hey, guys.Well, this is simple. When planning a flight, let's suppose you used Active Sky to depict weather, how do you know how much fuel are you gonna use during flight if you experience crosswinds, tailwinds or headwinds??Please try to make a general answer: avoid saying "I just program it in the FMS of my 30 US$-shareware-aircraft" ... I mean, I do have a little knowledge about scheduling the fuel burn because mostly, I use freeware add-ons besides FsNav, A.S and FsPassengers.Thank you so much for answering,fly7

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Well, Gustavo.First of all, thank you for answering.Now, focusing on the topic. Let's say I already know the weather and an average wind speed and direction during the cruise time. How can I know my GS? I'm sorry for not knowing it. Matter of facts, I'm just a begginer enthusiast not a real pilot. If I use the iFDG Airbus A320, how could I know my GS?Thank you

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>How can I know my GS?fly7:http://www.aerospaceweb.org/question...ts/q0210.shtml <<--this is the better resouce than below; be sure to follow the 'related topics' link "What is the difference between airspeed, true airspeed..."http://en.wikipedia.org/wiki/Indicated_airspeedyou need to confirm you have FS set to show indicated airspeed.groundspeed is also increased/decreased by the direction of the wind (jetstream). in USA aircraft heading east fly routes 'faster' than aircraft going west --- usually because the jetstream is going west to east giving the planes some extra knots of 'free' groundspeed. (this can be 100+ knots at times during the winter resulting in aircraft flying KLAX to KJFK, for example, arriving almost an hour early on the east coast). at the same time aircraft heading west may need to stop enroute for refueling as they are 'slowed' by 100+ headwinds.if you have been flying smaller prop aircraft in FS, like the cessna, the difference between groundspeed and airspeed are less (in no wind situations) as the pressure difference at a cessna's cruise altitude (5000' or so) is much less than a transport jet at 40000'.--

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Well, I spent some time reading throughout those pages but there's a lot of info and I thought to myself it would be wiser to ask with an example so you could teach me please.Let's say I'm doing a KJFK-KSFO flight. The fuel burn for the iFDG A320 at FL350 at 0.78 Mach is like 6.0 klb/h. Anyway, as this flight takes the A320 to its limits, let's suppose I'd be speeding the plane to 0.72 Mach. Obviously the fuel burn would be reduced as well. Now it gets to the TAS. The indicated airspeed is 0,72 Mach, right?. Then, to get the TAS, I would need the weather report. Again, let's imagine the average wind blows from west to east at a speed of 50 knots. So, what's my IAS gonna be? Should I transform the 0,72 Mach to knots in order to do the math?I know going against the wind current will definitively reduce my GS but how could I calculate if I don't know my TAS.Please, post an example of how you would do it.Thank you very much,

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Fly7,I also use Active Sky. For the "heavies" that I fly, I use a few programs, some freeware, some payware. I do all fuel planning in my pre-flight, never at the FMC. If I have to divert, I divert.Heavies: 767,737: I've downloaded freeware fuel calculators from AVSIM and other sites (check the forums for your aircraft). Some will computer fuel based on headwind/tailwind. I use the highest winds aloft windspeed in that calculation. I do not approximate if it is quartering- or cross-wind.I also use FSBUILD which will calculate fuel. But you need a PERFormance file for your aircraft.Cessna 172: No Planning, just full tanks ;) I used to break out the E-6B whizwheel along with a printout of winds aloft and the C172 manual.HTH,Jim

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I don't know if it was specifically stated, but, FSBuild will read the ActiveSky weather and use it when planning the fuel requirements for your selected aircraft and your planned route.

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fly7, For winds aloft conditions I use http://adds.aviationweather.noaa.gov/winds/ The pulldown menu on the upper left lets you select the flight level and then gives you a graphical representiaon of the wind direction and speed. I just estimate the direction and speed over my planned route and have found that to be very close to the values seen on Active Sky. There's also a metar tab that's great for getting the latest metars and TAF's For fuel planning, I've written a small Excel spreadsheet that's adaptable to any plane. It gives TAS, time enroute, and of course the fuel needed including a 1 hour reserve. Send me a PM with your email and I can send you a copy. Mike

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Any REAL airline pilots want to tell us what service they use to input winds enroute data into their FMCs?

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>> fly7,>> For winds aloft conditions I use>http://adds.aviationweather.noaa.gov/winds/ The pulldown>menu on the upper left lets you select the flight level and>then gives you a graphical representiaon of the wind direction>and speed. I just estimate the direction and speed over my>planned route and have found that to be very close to the>values seen on Active Sky. There's also a metar tab that's>great for getting the latest metars and TAF's>> For fuel planning, I've written a small Excel spreadsheet>that's adaptable to any plane. It gives TAS, time enroute,>and of course the fuel needed including a 1 hour reserve. >Send me a PM with your email and I can send you a copy.>> Mike>Any for Europe or other regions like this?

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Thanks for the info. This is what I use to work out my fuel!

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