You've got it. Cost Index is the ratio of fuel-related costs to time-related costs. A lower cost index means that you are placing more importance on fuel-related costs than on time-related costs. At the extreme, a cost index of zero results in minimizing fuel-related costs by flying at the maximum range cruise speed.It is incorrect (as stated previously in this thread) to refer to a cost index of zero as being the most economical. In the current climate of high fuel costs, it would certainly seem that minimizing fuel-related costs would be important, but don't forget all those salaries, utilization rates, connecting flights, etc. that cost more as the flight time increases.Don S.

Let me say that anything over CI 100 is pratically useless on the NG. CI is not something pilots dabble over, that's for the guys in the office (flight dispatch). Each airline has there own numbers according to their cost-savings-time etc. Pick a number and go with it. Here is an actual American Airlines sim training flight on the 800LAX..ANGEL 2.. TRM, PKE, J78, DRK, J96, IRK, BDF3, ORDgw 140,000fuel 30,000zfw 110,000res 4,800crz alt 5000'ci 60FLAPS 1CG 25%V1 148VR 149V2 154stab trim 4.7to power 22K/40at Looks like fun ;-)Best Wishes,[h4]Randy J. Smith[/h4]http://www.rawbw.com/~bdoolin/shinault/southparkcartmad.gif[h3]PMDG 747![/h3]Caution! Not a real pilot, but do play one on TV ;-)ASUS KV8 DLX | AMD 3200 64 | 1 GIG PC 3200 DDR | GIGABYTE 5700 ULTRA | ViewSonic VP192b 19" |