Cost index

[NEBOJSA]

I am not a pilot just wondering in the FMC, what cost index does Air Canada use on their larger aircrafts.

Thanks,Nebojsa

[tonysoprano]

Depends on the airplane and what we are trying to achieve. On the 767 a cost index can be 90 (normal) which gives us M.79 and close to econ fuel burn. Or it can be 200 which gives us M.80+ to achieve an on time arrival or better if we're late. Pilots can adjust it as required in flight. I'm sure the 787 will improve the fuel burn tremendously. The 67 is getting old. Hope that helps.

[yycflyguy]

Most of the city pairs that are not critical for connections are using cost index of 1 these days on the Airbus and Embraer to minimize fuel burn... it's all good when you are paid by the minute.

[KAG]

We use 13 to 20 for the 737. we cruise around .78 and we descend slow, transition around 255 KIAS...

[prop2jet]

Nebo: If you are looking for a more detailed explanation and are up to it, the link below might be of interest to you.

http://iata.org/NR/ContentConnector/CS2 ... terial.pdf

[tonysoprano]

We use 13 to 20 for the 737. we cruise around .78 and we descend slow, transition around 255 KIAS...

That's pretty respectable. Fuel burn is good too no doubt.

[pilotbzh]

the emb used 1 to 10, you get 10 and you have important connections or strong head winds.... used 0 a few times on red eyes fr the west because of curfew in yyz..... we run at .74 to.78 most times or 290 for the climb and descent...

[E-Flyer]

So when you set Cost Index 90... what is it? 90 what? 90lbs/min?

[complexintentions]

That link given has a pretty decent explanation. The cost index isn't a fuel burn number per se. These days we seem to use mainly in the 30-50 range for CID. That gives a cruise of about .83 and descent transition of 270 KIAS, cruise burn of 8,000kg/hr for the B777-300ER. The -300 and -200 use closer to 7,000kg/hr but same speeds.

[NEBOJSA]

Thanks everybody.

Nebojsa

[Four1oh]

I cheered yesterday seeing a CI of 19! We were smoking fast at 260 kts in descent!

[gustind]

Basically a lower number means more range airspeed with a minimum fuel consumption where higher values wil increase the cruise speed and fuel consumption for the calculated ECON speed.

The cost index is actually a very wierd calculation based on a variety of things: Fuel cost, maintenance costs, flight and cabin crew costs, leasing costs, schedule requirements, distance to fly, load and cruise altitude (with winds taken into consideration).

Ref:Lvl-D 763 Manual

[E-Flyer]

so I guess dispatch provides the flight crew with the cost index for the day?

[Lost in Saigon]

Yes, dispatch generates the cost index. It is shown near the top of your part of the flight plan. If you don't use the right cost index, you may not have enough fuel to reach your destination.

[Four1oh]

Just did a short hop this morning yyz-yul and was sipping fuel at with a low CI and a cruise of .67 and a 255 kt transisiton... and we were still early! The burn was only 1800/side. Man, that ole 200 would have been 3100/side the way we flew them(.78 lol)

[E-Flyer]

Yes, dispatch generates the cost index. It is shown near the top of your part of the flight plan. If you don't use the right cost index, you may not have enough fuel to reach your destination.

So if you were to average it out... what would be the cost index for a 767 or 320 ?

[Lost in Saigon]

The 767 cost index used to be 70 for all flights.

As a fuel saving measure, they now will adjust it from approx 17 to 70 to maintain schedule flight times.

If you have good tailwinds, they will reduce the cost index so that you use less fuel but still arrive on sched.

Occasionally they will increase it as high as 200 to make up for delays and late arrivals. Max CI for the 767 is 999.

[down3green]

We use CI of 9 to 13 on the A320. Not at AC though. Low CI are being used by airlines around the world to save fuel.

[Four1oh]

My last ground school they pulled out a chart showing times enroute for the type of stage lengths we fly vs the various CI's, and time saved vs additional fuel. They decided that there was no CI that was worth attempting to make up time if a flight was late. It just cost too much in fuel for too little gain in time.