Cost Index

[Mattnz]

Was just wondering if any of you guys have any idea what 'Cost Index' Air New Zealand use on their B733s, and A320's? And also Pacific Blue with the B738.

Cheers!

[travnz]

from what i have heard it is rather low, around the 20 mark

[Daniel]

I don't even know what the cost index is
Can someone explain??

[Anthony]

Have no clue what it is or what Air NZ uses but I looked on Google and apparently the higher the cost index, the faster you cruise but the more fuel you burn.
British Airways apparently uses 28.

[Alex]

QUOTE (Daniel @ Jul 31 2008, 07:15 AM) <{POST_SNAPBACK}>

I don't even know what the cost index is
Can someone explain??

I can give a brief explanation. It's used in FMC's in airliners, a two-digit number (I don't think goes into three digits?), and determines how economically the aircraft will fly. A higher cost index gives you a faster climb and cruise etc. (at least that's my limited understanding of it).

Alex

[AlisterC]

A couple of guys from my work have been on Pac Blue jump seat rides lately, I'll get the info off them or get SeanG to reply himself..

[SeanG]

On my rides they used a *very* low CI or 10, yes 10!! But then made changes to the calculated N1 to meet their schedule requirements.

Cost Index is basically a calculation function of the Flight Management Computer. 100% is "all performance and no concessions to economy" (Makes the accountants grumpy), 0% is "all economy and no performance" (Spot the one that accountants would like!)

The FMC takes the Cost Index and uses that to calculate things like cruise, climb and descent speeds, Engine performance (N1) and climb rates. As an example on the takeoff from Christchurch at 55.1 tons and 10% CI we had a takeoff N1 off 86.5 (which is bugger all) with an initial climb at 175KIAS. Try that in PMDG it's quite interesting!

Hope that helps a bit ;-)

SeanG

[benwynn]

Depends on the Route and a heap of other factors, its different from CHC-WLG and WLG-AKL. But yeah, they range from 10-30.

But for example, CI's as high as 99 are used occasionally on routes from HKG-LHR when flights are delayed etc- I think SeanG has mostly summed it up

[AlisterC]

Thanks for that Sean! Might explain why my Level D launches into the sky like a rocket with a CI of 70

[Mattnz]

Thanks a lot, guys!

[SeanG]

QUOTE (Mattnz @ Aug 1 2008, 12:51 PM) <{POST_SNAPBACK}>

Thanks a lot, guys!

You're welcome... forgot to mention too... I was on Pac Blue, and despite being late on departure from Christchurch on the first flight (Weather in Welly), we still used 10% CI and finished the shift back in Christchurch (at 2 or 3 in the PM) on time... them NG's can go when they need to!

SeanG

[Daniel]

Thanks for the info Sean
Interesting stuff about all of these different things.

[Anthony]

Thanks for letting us know more about cost indexes and all that Sean.
Quite interesting.

[SeanG]

No probs at all.... But I tell you something, as a fast jet guy, I am starting to learn a disturbing amount about airliners. Might have to go blow something up to restore the natural order to the universe ;-)

SeanG

[Njbb1995]

Yea I just learnt more there than at school this week!!!

[spongebob206]

Very Interesting.

Thanks Guys

[Daniel]

Don't know if anyone still wants to know about what Air NZs use for there cost Index...
Anyway I went on a few 733s with Air NZ and asked what they used,
The use a cost index of 35 on Domestic Flights.
On International they use a cost Index of 20.