Cos Index way over 100 seems realistic. Correct?

[JSACKS 0]

In fiddling with the CI function on the FMC, I am finding that a range of up to 180 and even 200 in the CI field seems to produce a realistic climb and cruise speed, depending on the Gross ToW. But certainly a range of 100-150 seems fine based on my RW experience of cruising at Mach 0.86 - 0.865.However, the manual suggests a CI range of 00 to 99 only. Why is this?Jonathan

[Kosta 122]

British Airways use CI 100 for 747 afaik.

[Guest Jock in a Frock]

Isn't the Cost Index unique to the operator? i.e. Doesn't BA's CI of 100 differ from, say, Quantas' CI of 100? I was under the impression that it was scaled to the specifications of the operator, not a rigid figure from Boeing.Andy Scholes

[Tabs 2,790]

>Isn't the Cost Index unique to the operator? i.e. Doesn't>BA's CI of 100 differ from, say, Quantas' CI of 100? I was>under the impression that it was scaled to the specifications>of the operator, not a rigid figure from Boeing.>>Andy ScholesDon't believe so (I'll ask Vangelis to be sure) but I think what's meant when people say CI is operator specific is the actual setting itself, ie Airline X uses 85, while Airline Y uses 100.

[Guest Senior Captain]

Actually British Airways uses a CI of 90 and yes a CI of 90 or whatever is the same for any airline that uses it. A CI of 100 and up is used if the winds are strong enough or the aircraft is trying to make up time to get to their destination on time. Hope that helps.

[Check_Airman 3]

i think when the manual was written, the CI function was not modelled fully, so it was limited to 99. They have now fixed it, so now CI of 100 or greater can be used.Paul

[JSACKS 0]

Aha! OK, Paul, thanks!Jonathan

[Guest 73G]

Hi,The CI normally used by KLM is 150. In case of a possible delay it can be 400 to catch up the lost time.

[chiswick72 145]

I know of one major 744F cargo operator that always uses a CI of 250, in normal operations.http://www.bootus.co.uk/pilotinfo.gif

[744pilot 0]

Qantas uses 200.

[JSACKS 0]

Clearly, then, a whole array of CI scales abounds. Jonathan

[kmanning 12]

>>In fiddling with the CI function on the FMC, I am finding that>a range of up to 180 and even 200 in the CI field seems to>produce a realistic climb and cruise speed, depending on the>Gross ToW. But certainly a range of 100-150 seems fine based>on my RW experience of cruising at Mach 0.86 - 0.865.>>However, the manual suggests a CI range of 00 to 99 only. Why>is this?>>JonathanAre you saying that the cost index has an effect on the rate of climb and the cruising speed? It has crossed my mind. Ken.