Cost Index

[Mike S KPDX 597]

bumped from page 7...again, why is it that the manual states the CI ranges from 1-999 but you can not input ranges above about 500, is this a typo? What exactly is the range within this product? Does the program actually recongnize these mins and max? if not - to what min/max range does it actually use in the calc?

[Mats_J 2]

MikeThe manual is wrong. (Sorry to say Cpt Rozarro ;-)) The NG has a range for CI of 1-500. Or was it 0-500? If you have the -800/900 you should be able to see the differences choosing high or low values on CI.Hope it helps,

[victorlima01 2]

100 works fine for me. Hey, I don't pay for the gas man. Might as well make use of it. ;) But for shorter flights (for example routes of 220NM with FL300 as cruise) it might be best to choose lower numbers since you might get your T/C way too close to ToD. Something I truly don't understamd is a low-fare airline from Brazil called Gol which routinely files the flightplan for SBRJ-SBSP (only 215NM) as follows: N0426F370. I have no idea how they find the space to crawl all the way up there. I don't think my PMDG 37s can do it even with negative CIs! And I don't get what's the point of climbing to 370 if you're gonna be hanging there for like 2 min. anyway... way off topic now... but CI-related nonethelessRegards,Victorhttp://www.precisionmanuals.com/images/forum/800driver.jpg

[Guest]

Seems a bit high but a dash like that with T/D being almost on top of T/C is quite normal.It's the way many flights between close city pairs are flown. Think of Amsterdam-London for example.

[Guest Knikolaes]

Plain and simple, the PMDG can handle any Cost Index as needed by either the user or the airlines. I just wish i knew what Delta Airline's standards were, since they are the VA I fly for.

[fozzy 1]

I'll bump a thread from over a year ago... While flying today in my 737 700 with a particular eye on fuel economy i noticed some strangeness... Starting the flight on CI 1 i had an arrival fuel level of 3.0 in the PROG page (yes i know it's low got strong headwinds...and 2 more hrs flight to go) switching to a higher CI gave me a higher speed and more fuel on arrival :| Am i missing something here or is this wrong? I then made a small test with a short flight (identical setup same route) flown once at CI 1 and once at CI 100 trying to keep them as similar as possible... fuel consumpiton in the end was absloutely identical (to the 10 lbs...) I have the PMDG 600-700 and upgraded to 800-900 with model update... Any insight as to the absolute fuel economy on the PMDG 737 700 in FS is welcome :) Luca

[cowpatz 243]

On the 747 if you enter 0 you will get long range cruise. I should now the top value but cant at the moment. But if you enter the highest value you will get the aircraft climbing, cruising and descending on the Barbers pole. Some operators just use a cost index taht equates to about a .84 to .85 cruise and that is about 100 on the 747. Due to the high fuel costs at the moment we are back to a cost index of 50. It actually saves bugger all fuel (about 300kg on a 12 hr flight) but adds about 8 to 10 min to the flight time. Our diversions are done at cost index 0.The atlantic crossing is done at a fixed mach speed that is given to you in ATC oceanic clearance so the cost idex econ cruise is not used.You can vary the cost index in flight so why dont you experiment and see what happens?CheersSteve

[michal 44]

>On the 747 if you enter 0 you will get long range cruise. Steve,Based on my Boeing developed Computer Based Training material for pilots Boeing defines Long Range Cruise (LRC) as the way of flying that will result in 1% higher trip fuel burn than your absolute least-fuel trip. If this is true then the LRC should correspond to slightly higher cost index than zero. They argue that LRC is a very clever sweet point that offers still excellent fuel economy but with higher cruise speed. Michael J.http://www.precisionmanuals.com/images/for...argo_hauler.gifhttp://sales.hifisim.com/pub-download/asv6-banner-beta.jpg

[cowpatz 243]

As far as my training goes cost index zero is, or is a s close as you will get to long range cruise. You could go slower and get Maximum Range Cruise (MRC), which as you point out is about 1% fuel burn less but in reality it doesn't seem to work out that way. The MRC speed is not a stable one and the autothrottles have to work harder to maintain the speed. In a practical sense it uses the same ful as LRC. It is a theoretical value. I will see what info I can drag up on it and get back.CheersSteve