A320 Cost Index

[GearDown&Locked]

Could someone explain the real use of the Cost Index?
And what are the most common values that you use?

GDL

[Phoenix_X]

The use is to define the balance between aircraft cost and fuel cost.

It makes a balance between the following:
Flying slow/economic speeds (Low cost index):
* Less fuel burn/cost
* More aircraft time/cost
OR
Flying faster/less economic speeds (High cost index):
* More fuel burn/cost
* Less aircraft time/cost

The more expensive fuel gets, the less the aircraft costs relative to fuel burn, and thus the lower the cost index. This is the case nowadays, since fuel is now relatively expensive.

We fly a cost index of 30, which most airlines I hear of seem to be around (but prove me wrong :ok: ).

[NigelOnDraft]

And what are the most common values that you use?BA use 20. I use 45...

NoD

[leander]

CI 45 instead of 20 costs the company more fuel.

CI 45 instead of 20 reduces the statistics re required time to complete the flight , which leads the company to reduce the schedule for next year, which causes all pilots to screech about trying to achieve the new schedule.

Good on ya.

[BigHairyBum]

BA use 20. If running late and std is still within grasp then why not increase it.

Otherwise stick to the sop index. :hmm:

[GearDown&Locked]

I would like to thank you all for the replies.

So, as I understand it, its an exclusively company dependable variable. But does it limit the overall performance of the a/c or just limits the cruise/top speeds, like your regular BMWs or Mercedes?

[BigHairyBum]

Modifys the climb, cruise and descent speeds.

So, a/c performance then. It is all over-ridable though.

[Maverick]

"The more expensive fuel gets, the less the aircraft costs relative to fuel burn, and thus the lower the cost index. This is the case nowadays, since fuel is now relatively expensive."

Dear Phoenix . Can you please tell me how the aircraft costs less relative to fuel burn. I am a budding pilot and my knowledge about airline operations is minimal. I have my CPL and will be going for my Initial A320 rating soon.
Thankyou.

[Felix Lighter]

Not A320 but A330/A340:

My company uses CI60 as standard but we are sometimes asked to use CI150 if winds are not favourable.

Above CI150 you are basically turning fuel into noise for very little gain in time.

On a 12hr flight if you plug in CI999 you make up 6-7minutes (well you would do if you didnt run out of gas 1000nm before destination)

If we are excessively early we'll use CI0 to save the company some ca$h but this is not mandated..... by the company.

Over SARs many companies used CI0 and just accepted they would be late..... Saved money and annoyed the very few passengers that bothered to fly!

Maverick the answer to your question lies in the huge quantities of gas we are talking about. An extra 15mins of engine time is negligable when considering the cost of Avtur.

If each aircraft in our long haul fleet safed 1tonne (1000kgs) per flight..... then we would save enough gas each day to send a A340 12hrs for free! Obviously its not really free but it is below budget and therefore falls on the good side of the balance sheet.

[Phoenix_X]

Maverick,

An aircraft costs the airline money in (some or all of these):
- Lease cost
- Maintenance
- Crew on board
- Many more

Now all these costs can be brought back to an hourly cost of the aircraft.

If it flies faster it will spend less time in the air, thus requiring less maintenance (most maintenance has to be done after xxx flight hours) and crew, etc. This reduces the aircraft cost mentioned above.
Also it might be able tocarry more passengers per day, and thus make more money (this is debatable, as the cost index changes flight time only very little, so it would have to be a very short extra flight).

However, flying faster costs more fuel. So those costs go op.

Now with 'the aircraft costs less relative to fuel burn' I meant that the increase in fuel cost is more, than the decrease in aircraft costs, so it gets more expensive overall.

Hope this is clear? (I've been known to write unreadable nonsense :))

[Spearing Britney]

leander's post merits attention from many. Company bean counters specify cost indices based on complex calculations that I am too stoopid to query. Routine use of higher ones does what leander says it does. That is bad news for us, and it gives me heart trouble looking for the overspeeds when you put in 911!!

Some file a report if they have selected higher speeds/used a higher index, it's probably naive to believe this will find its way to the relevant bean counter but the union reps can at least use them in complaining about the un-realistic block times allocated to next years schedule...

[Maverick]

Phoenix ,

Hi; Thank you for your time and effort to explain 'cost index' to me. I understand clearly.

Cheers !!!

Mav...