GNLU-910A: What speed for ALTNs?

[Capn Bloggs]

Could anybody enlighten me as to the speed the box uses when calculating the alternate details? We can put in the wind and the level, but what speed does it use?

[VRThomas]

I don't know what "box" in particular you are referring to but our dispatch system uses max range speeds. This is in order to minimize the amount of fuel to plan for and therefor carry to destination.

VRT

[Capn Bloggs]

VRT,

The "box" is the Collins GNLU-910A. There appear to be no crew-available inputs for the speeds for the Alternate Airport display, and I was wondering what it actually uses to work out the fuel and time to the alternates.