Wind value in FMS
 

Dear all,
I'm an Air traffic controller and I'm working on a project for the italian provider of ANS concerning data exchange between a/c and ground systems.
At this time, I got a question for the pilots attending the forum: is the wind value inserted in FMS for the Flight profile calculation purposes a forecasted one? If yes, how many hours before the flight it has been calculated?
And, is there any chance to update the value (direction, strenght) when airborne?
Thanks

The forecast winds tend to come from the flight plan, for FL300, 200 and 100 and are entered into the FMC prior to the descent.

The time of the forecast used varies , but for flight plans printed say 1 hour prior to departure, by he last sector of a long day I imagine the forecast could be up to 12 or 18 hours out of date depending on the system and the model used.

In the 737NG, any direct routing executed on the descent automatically inputs the present sensed wind into the FMC calculation process.

It depends on the operator, the wind forecast vendors used, and individual pilots.

Most airplanes with ACARS have the ability to upload forecast winds at any time before and during flight. If ACARS is not available, winds from the flight plan will be used, which may be as much as 20 hours old at the end of a long flight.

Those who update the winds inflight can get forecasts less than 4 hours old. Forecast altitudes depend on company SOPs and pilot input preferences.

In my company flightplans are calculated 180 minutes prior to EOBT and use the latest available forecast winds. As Intruder says above we have the ability to download winds directly into the legs and descend forecast page and do so at least once a flight, on longer flights more often. Those winds are then from the latest winds aloft info and on the planned cruise level and descend winds for FL310/200/100. Updating descend winds just prior TOD or during initial descend will give a very accurate wind profile resulting in an on speed ECON descend until vectors are given. Age of the wind data depends on update cycle of that information, downloading always gives the latest info.