Fuel at destination

[Richard McDonald Woods]

Without entering en route winds into RTE DATA, I get a calculation of fuel at my destination.
If I now enter a changed wind vector and speed into RTE DATA, I receive a modified fuel at destination calculation.
If, subsequently, the wind changes either direction or speed, will the fuel at destination calculation now be based on the new wind direction/speed or on the value I have already entered into RTE DATA?
Regards, R

[Jeroen Hoppenbrouwers]

Very briefly, the FMC uses a mixing algorithm.

For current position, winds are known from the IRS. The FMC projects these winds ahead, gradually replacing them with the forecast winds from the LEGS page (if any).

The details are complex, and somebody else undoubtedly will key in half a FMC manual tonight   :twisted:

[Richard McDonald Woods]

Thanks for the resume, Jeroen!
I shall await the full volume from someone else, if they dare!
Cheers, R

[Maurice]

Following Bill Bulfer's FMC User's Guide, at the aircraft's actual position, the computer uses 100% of the actual winds. At 200 nm in front of the arcraft 50% of the actual wind and 50% of the forecast wind. Over 200 nm, the FMC will use successively less measured wind until the wind used is near 100% forecast.

Same mixing algorithm in the climb and descent phases, except the distance from aircraft is replaced by altitude in feet and the limit of 200 nm is replaced by 5000 feet.

100% best wishes for 2010 and ... PsX !

Maurice

[Joe Clark]

If someone wants to post the full volume, I (and I'm sure others) would like to read it

[Hardy Heinlin]

If someone wants to post the full volume, I (and I'm sure others) would like to read it

What Maurice wrote is actually the "full volume". The mixing is as simple as that. It's also described in the PS1.3 manual on page 172.


Cheers,

|-|ardy

[Jeroen D]

It's also described in the PS1.3 manual on page 172.

When everything else fails, check the manual!

Jeroen