In my company we used the average wind as well. However, last year, due to the economic crisis there was a real push to drive the fuel usage back.
We got a couple of "memo's" on how to fly fuel efficient. One was indeed to use top of climb wind and then change the winds on the legs page whenever the winds changed by more than 10kts or 10 degrees.
I tend to do this whenever there is sufficient time in the preparation fase. I do think though, it's either the one or other option. Either you use the toc wind and adjust the winds on the legs page, or use avg winds.
If not it will screw up your times and fuel predictions.
I like the first option. Flying for a large carrier with thousands of flights a month, even a saving of a few kgs per flight makes a difference!
edit: I didn't read the initial question right. No sense in using the TOD wind. TOC allows the FMS to calculate the most efficient climb speed, however, since this entry propagates forward all predictions would be messed up. So you will have to adjust the speeds on the legs page whenever they differ from the TOC wind. TOD winds only help calculate the most efficient point of descent.
Actually, pretty basic stuff. TOC winds allow the FMS to calculate the most optimum climb speed, TOD allow the FMS to calculate the optimum TOD, winds enroute allow the FMS to calculate accurate predictions.Fill these in during preflight and you would get an accurate picture of fuel usage. Should be basic knowledge taught during ATP theory training and enhanced when reading the FCOM
Last edited by flyburg; 17th July 2010 at 23:30.