Just a quick question. When you load the flight plan in to ASX and look at the Briefing page, at the bottom, it shows the "Averages" (276/40) Beneath that, it says "Wind Component" and in this case, a -29. What exactly does the -29 refer to?

Hi,Its a relative value. The - means a headwind a relative strength of 29. But don't take this as a headwind of 29 kts.Thanks,

Jim, For planning purposes, should I use 40 knots as a tail wind since the average is 276/40 and there is no minue? Thanks

Hi,No, the actual average winds are going to be 276/40. For your plan this is going to be a head wind with a relative strength of 29.Thanks,

Hi,No, the actual average winds are going to be 276/40. For your plan this is going to be a head wind with a relative strength of 29.Thanks,

Jim, I'm confused... didn't you say that a - would have been a headwind? As I'm flying it right now, its a tail wind consistent with what ASX has prescribed. It has to be a tail wind, I'm flying west to east and the winds are 276/40???

Hi,Are we now talking about the average data or the Wind Component value?Thanks,

Hi,Are we now talking about the average data or the Wind Component value?Thanks,

Jim, we're talking about the Average data. I'm looking at a plan now that says the following: Wind Dir - 257 and Wind Spd is 43 (257/43) This tells me that I have an average tail wind of 43 knots..... if this is correct, if I had a head wind, would it be preceeded by a "-" minus?

Hi,The average data is only going to tell you the direction of the wind and the speed. They will always be positive values and do not take into account your direction of flight. Now, in your example, if your plane was flying 257 you would have a full headwind. If you were flying 77 you would have a full tailwind. Anything else would be a portion of these.Thanks,

Hi,The average data is only going to tell you the direction of the wind and the speed. They will always be positive values and do not take into account your direction of flight. Now, in your example, if your plane was flying 257 you would have a full headwind. If you were flying 77 you would have a full tailwind. Anything else would be a portion of these.Thanks,

So then is ASX not capable of giving you a true average wind direction and speed for fue planning purposes based on the flight plan? Of is there a better tool within ASX to do it with?

Sorry I'm thoroughly confused.I have always taken Wind Component to be the average tailwind (+) or headwind (-) in KNOTS arising from the average wind for the route.That always seems reasonable based on the average route wind and my average route heading - it's positive when it should be, negative when it should be, it's always a number lower than the the average wind velocity (and I presumed the same if dead ahead) and the ratio between the two varies with the relative angle between the average wind direction and my heading. It seems to tie up roughly with the wind components I see on the panel of my aircraft. On that basis, I have always assumed it's knots and never checked the calculation in detail!For example, I just processed a flight plan of mine - the flight is in a broadly south westerly direction and the average route wind I'm getting is 264/77 i.e. more or less a westerly @ 77 knots, on average. The wind component is -47, which I'm taking to be a average headwind of 47 knots (sounds about right) plus an (unmeasured) crosswind component which is going to blow me to port (i.e. south east-ish). Of course, I understand it's an average for the route, not the actual wind on any particular leg.If it isn't in knots, what is the average wind? i.e. -29 in the example given?Is it a percentage I can multiply the average wind velocity by to arrive at an average head or tailwind component?This isn't an academic question - certainly my aircraft of the moment - the PMDG MD-11 - requires the average route head or tail wind (and temperature) to be entered into the FMS, which I presume it uses for fuel consumption figures amongst other things. The doesn't appear to be an RTFM issue - I checked!

Hi,Yes the unit would be kts.Thanks,

Hi,Yes the unit would be kts.Thanks,

Here is a good test.... but it only works for domestic routing.... I've been comparing it with AVSIM.... put the depature and arrival airports in, then on the next page, use the leer jet as the selected aircraft.... copy and past the route in there, without the sid and star..... http://www.fltplan.com/AwFmsNewFlt.exe?CRN...&end=MSGend

Thanks - had myself worried there for a minute!