Greetings,
1.3.2.2.1 Wind modeling
The Wind modeling follows the flight in its logical order, departure,
climb, cruise, descent, and destination.
Because of similarities, we can pair
Departure and Destination
Climb and Descent
1.3.2.2.1.1 Departure and Destination winds:
These winds refers to wind below from 400 ft AGL to 0 (GRND)
1.3.2.2.1.2 Climb and Descent Winds:
Climb and Descent Winds can be defined for 5 altitudes.
Each altitude and its associated wind magnitude and true
direction, is either defined by the pilot or up linked if AOC
function is available.
Furthermore, during Descent, the FM will record the wind at the
Cruise FL, then at FL, 250,150,050, and store these recorded
winds in the History wind page.
Considering that while in transit the turn around time is less that
it takes to the wind to change, the crew can select the history
wind values, and use them as data for the next climb.
1.3.2.2.2 Wind interpolation:
1.3.2.2.2.1 During climb:
If the predicted altitude at a waypoint is above the Highest
entered wind altitude, then the predicted wind at this
waypoint is equal to the Highest entered wind magnitude and
true direction.
If the predicted altitude at a waypoint is between 2 entered
winds altitudes, then the predicted wind at this waypoint is
equal to the linear interpolation between the 2 entered wind
magnitude and true direction.
If the predicted altitude at a waypoint is below the lowest
entered wind altitude, then the predicted wind at this
waypoint is equal to the linear interpolation between the
lowest entered wind magnitude and true direction, and
000/00kt or the GRND data if available.
1.3.2.2.2.2 During Descent:
If the predicted altitude at a waypoint is above the highest
entered wind altitude, then the predicted wind at this
waypoint is equal to the linear interpolation between the last
predicted cruise wind and the highest entered wind
magnitude and true direction.
If the predicted altitude at a waypoint is between 2 entered
winds altitudes, then the predicted wind at this waypoint is
equal to the linear interpolation between the 2 entered wind
magnitude and true direction.
If the predicted altitude at a waypoint is below the lowest
entered wind altitude, then the predicted wind at this
waypoint is equal to the linear interpolation between the
lowest entered wind magnitude and true direction, and
000/00kt or the GRND data if available.
1.3.2.2.3 Wind blending during climb and descent:
During Climb, The FM will blend the actual measured wind with the
predicted wind 2000 feet above the a/c altitude until the
T/C is reached.
During descent , The FM will blend the actual measured wind with the
predicted wind 2000 feet below the a/c altitude, from the
T/D until 400ft AGL.
1.3.2.2.4 Cruise Wind:
Forecast wind is determined at each waypoint and pseudo waypoint along the
F-PLN in the following way :
Cruise wind input data is propagated on the CCRZFFPLNwaypoints until another cruise wind input data is found and so on up to the last CRZ waypoint.
T/C forecast wind (or A/C actual wind) is propagated up to the first cruise wind input data before entering to CRZ phase.
After CRZ phase is entered, A/C actual wind is propagated upto the first cruise wind input data.
1.3.2.2.4.1 Wind ENTERED n cruise waypoints
The FM bBlends wind linearly from actual measured wind at PPOS to ENTERED wind on the upcoming (next) waypoint in cruise when within 100NM: at 90nm uses 90% ENTERED wind and 10% actual emeasured wind, at 80NM, 80% ENTERED wind and 20% actual measured wind, at 100 NM the FMS uses 100% of ENTERED wind
To compute the predictions, the FM then interpolates between act wind and BlendedEEENTERED wind linearly same scheme within 100nm
PLEASE COPY PASTE BECAUSE THEY WONT BE ANOTHER EDITION, AND THIS IS VALID FOR THE LONG RANGE FAMILY ie A340 A330