Also don't forget that we aim for minimum cost, rather than minimum fuel.
Ok, am learning too . . .
Do you mean, the longer you are up there it costs more but your fuel flow is lower . . .? Thereby, if you skittle on down and get slotted into the flow of things (traffic) then you burn more . . (?) . . but you get there quicker . . .?
but anyway, can you explain what you mean here, please . . .(thirsting for knowledge)
OK. And your point is exactly? That guys are not flying fuel efficient in your company?
Am not really making any point just musing. I`m just saying there are a lot of different descent patterns and at the end of the day they seem to be as fast and effecient as the other as the bus tends to burn less fuel and the amount in descent is "academic" in the sense that it is not all that much fuel, unless you are going to descend level out for long periods, descend then level out again.
While we are here though, I worked out the difference between say Mach0.81 and .78 is only going to give you a saving over 1.5 hour of 60 miles, but you will have burned the extra and been merely 60 miles back or ahead depending on the your Machno.
That the bus is so refined in this context that it is already fuel effecient as a design aircraft and to try to tweek anymore out of it is like adding sugar to candy floss.
As it can back calc the descent from T/D to ROD whether it is 280 then 250 then green dot or whatever so that in an ideal world of no traffic, no weather and nothing to hit, it will descend at idle maintaining a seemless 3 degree descent - my only qualm is the early reversion (for want of a better word) to approach speed - solution: go Selected until you are ready for the approach (speed).
Rather than evaluate the possibility of saving fuel in the descent by concentrating on a particular speed, it might be more cost effective to consider the descent profile and descent management instead.