B777 FMS Wind Uplinks
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B777 FMS Wind Uplinks
From the B777 FCOM :
6)LIDO uplinks four wind forecasts. These are the cruise level, two
below and one above. E.G. If the cruise level is FL350, then the
uplink would be FL280/310/390. The ALT/OAT on the wind
page will be that for the cruise level wind uplink only on initial
request, which in the above example would be FL350. Any wind
request after the initial, the ALT/OAT will be for the highest
cruise level wind uplink. LIDO then uses a standard lapse rate
conversion for the other levels. This may not always be correct.
To obtain a more accurate wind and temperature forecast, delete
all levels except those that you require and then REQUEST
WIND DATA again from the wind page. When the WIND data is
uplinked by this method, an inbuilt filter will uplink winds at an
interval of 249 nms.
Has anyone seen this happening inflight? I have never seen this - is it an option which has not been activated on our fleet?
6)LIDO uplinks four wind forecasts. These are the cruise level, two
below and one above. E.G. If the cruise level is FL350, then the
uplink would be FL280/310/390. The ALT/OAT on the wind
page will be that for the cruise level wind uplink only on initial
request, which in the above example would be FL350. Any wind
request after the initial, the ALT/OAT will be for the highest
cruise level wind uplink. LIDO then uses a standard lapse rate
conversion for the other levels. This may not always be correct.
To obtain a more accurate wind and temperature forecast, delete
all levels except those that you require and then REQUEST
WIND DATA again from the wind page. When the WIND data is
uplinked by this method, an inbuilt filter will uplink winds at an
interval of 249 nms.
Has anyone seen this happening inflight? I have never seen this - is it an option which has not been activated on our fleet?
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B777 FMS Wind Uplinks
Upper air data is processed in Lido at 00:00, 06:00, 12:00 and 18:00 UTC; the updates are available for upload into the FMC 4:30 hours later, i.e. 04:30, 10:30, 16:30 and 22:30 UTC.
Last edited by victorpapa; 2nd Nov 2014 at 20:37.
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No Meaningful answers as yet...
....this is the real questions! Does this happen automatically?
When the WIND data is uplinked by this method, an inbuilt filter will uplink winds at an interval of 249 nms.
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An evergreen discussion topic this.
There are those who interpret the 249 NM as referring to the geographical segmentation of the wind update, i.e. same winds applied to all waypoints within the 1st 249 NM on the route, then the next wind for the following 249 NM etc.
This instead of LIDO providing more accurate individual wind data for each waypoint (with less than 249 NM apart).
I.e. nothing to do with any winds being updated automatically (requires an execute on the FMS normally as we all well know).
Check next time when performing an update like this.
Would like to get the full explanation from the source myself as well though.
There are those who interpret the 249 NM as referring to the geographical segmentation of the wind update, i.e. same winds applied to all waypoints within the 1st 249 NM on the route, then the next wind for the following 249 NM etc.
This instead of LIDO providing more accurate individual wind data for each waypoint (with less than 249 NM apart).
I.e. nothing to do with any winds being updated automatically (requires an execute on the FMS normally as we all well know).
Check next time when performing an update like this.
Would like to get the full explanation from the source myself as well though.
