B777 200 ER Cost Index and slow decent

[setvfs]

Hi to all B777 Operators. I am trying to get some information from other 777 operators on what cost index you use. We have started using cost index 50 which is all well and good apart from the lame 257Kt decent speed.
I have worked out we save around 100kg each decent and cost us around 2 minutes of flight time. I am not sure what 2 minutes in a B777 cost but I am sure it is more than $100 usd.

So can you post your operating cost indexes and what airline please. If any one has any good info on costs of fuel in decent that would be appreciated. This slow decent is causing me nightmares where ever I go with ATC so I need some good info to talk my company out of it.

Any one have any numbers on fuel savings with flap 25 landings.

Thanks

[ACMS]

here in CX we normally use CI 60

If we are early and not in a hurry we are advised that CI 20 gives the lowest fuel burn.

Whatever CI we use we are supposed to descend at cruise Mach/300 KIAS.
That's what ATC expect, if it's not busy then by all means ask ATC if you can descend at Econ.

ok?

[mabrodb]

The avg. Time Dependany Mx costs (TDMC) for a 777 are in the $750-$1000 USD range.
Avg. worldwide fuel costs are on avg. around $2.20/USG at the moment (OCT07).
That would yield a CI of btween 23 and 30, based on 6.75lb/usg density.
This of course is based on crews/stews being paid a fixed 70-80hr/month rate and that the flt is operating on-time or under block.
If operating late/tardy, then some addnt cost fig. for a slight crew/stew OT rate and pax misconnect charge (e.g. WAG of $30/min over :15min late), would change the hrly cost to drive a CI in the range of 85-75 if between :15-:60min late.
After about 60min late, the cost-model drops off the cliff, and most INTL connections are blown. Which then lends itself to backing off the CI to the original CI 23-30 figures.

FWIW, depending on GW, the CI50 kias descent speed is around 266-257kias.