Well guys, just a short update: I´ve just made a little test flight from KCLM to KEUG. Take off and departure were unproblematic and thus of the new cost index of 36, as some airlines use it, the cruise on FL260 with M 0.74 was no problem. Long before descent I configured the FMC for approach: This time it was the ILS RWY 16R at KEUG via transition CVO. The initial descent went well with 280 kts as predicted but slowly the plane was gaining speed again as the VNAV forced to descend with 1600ft VS. At the end, when we should slow down to 240 kts we were at 310 instead of 280 kts and I had to get the speedbrake out to get us on the speed. And after turning on the LOC I got "VNAV path unachievable" and had to slam the gear and flaps + speedbrake out to slow down and fly the GS properly.Just a little note: Through the whole descend and APP the engines were running at about 43% and never really changed. I thought they should go down into IDLE for descend as it works in most other planes.

Something to look at - if you press INIT REF while descending, you'll find it switches to offer a landing profile. On the right are three landing speed options with flap settings. Click one and it'll load it up onto the PFD. Use this as a reference for a nice smooth landing. It's calculated based on your weight so this is where good fuel planning comes in. When I first flew the NGX I didn't set fuel so I was bombing around with a full tank! On a 55 minute trip to Jersey that didn't burn much and I'd be piling down to the runway at 165kts/40flap and just about stop on the taxiway at the far end of the runway! Thus I knew something was wrong. I performed the reference flight in the PMDG manual and oh looky, FS Actions - fuel & payload + INIT REF = happy pilot and smooth flight. Next flight to Jersey and approach speed of 137kts with 40 flap. BIG difference, stopped after only 2/3 of runway used!!!Keep trying, you'll get it :) The more you learn, the more you'll be in control :)***In response to the speedbrake issue, I thought the same - I shouldn't be extending the SB in flight (even if it is only in the flight position), and that was the same thing some sim pilots told me on BAv forum. However, I am also an ATC operator in the VATsim SWRTS and one of my colleagues is an Easyjet pilot, so I asked him about descending through flight levels, i.e. would you have a long, low V/S descent but spend a lot of time crossing flight levels and potentially intercept many aircraft... He said no, you should try to stay at your cruise altitude for as long as possible then make your decent. You'll find that the VNAV mode of course posts T/C and T/D on your flight display. They seem to tally nicely with this approach. However I accept that different airlines may recommend different procedures :)

Hmm, I know this FMC page and used it as I did in FS9 with the old 737 and 747. But I forgot to do a proper fuel planning. Just loaded the plane with full tanks and off we go. But I'll do a proper one when I'll take her back to KCLM. Btw what do you guys use for fuel planning? Is there any tool for that?!

This has nothing to do with Cost Index. Fix your idle problem and you should be able to VNAV without getting 8000ft high. You should be around 39% N1 at 37000ft and it should drop down to about 30% by the time you're ready for the approach.

...Btw what do you guys use for fuel planning? Is there any tool for that?!

The FMC is awesome for fuel planning, very accurate in my experience

This has nothing to do with Cost Index. Fix your idle problem and you should be able to VNAV without getting 8000ft high. You should be around 39% N1 at 37000ft and it should drop down to about 30% by the time you're ready for the approach.

You're right!There are some people with this problem.Idle is not related to the cost index, most of the descend are planned by the FMC to be in idle, cost index will only change TOD (so the descent ramp) and speeds, but almost all the time it will try to stay at idle. It will change from idle only at restrictions or with head winds not i forecast page.So, if he is having troubles slowing down in all flights, it is mostly related to the idle issue or incorrect des forecast compilation.

Btw what do you guys use for fuel planning? Is there any tool for that?!

I heard that this one was good:http://www.topcatsim.com/Bert Van Bulck

Cost Index for Various Airlines

Paul that list is stunning! Where did you get it??

Boeing article with CI's.http://www.boeing.com/commercial/aeromagazine/articles/qtr_4_07/article_05_3.htmlBert Van Bulck

You´re right on this. It isn´t just hop in and push the throttles. I really have to practice again.

First, one should study the literature, then fly a tutorial.Either you let the FMC calculate your route and then you should modify it to observe annunciations, or prescribe your own data. Just don't expect an aircraft to do whatever you want in the latter method, just whatever it is designed for.The lower ability to decelerate, indicates efficient aerodynamics.

Hi guys,I´ve made several flight with the NGX since I got her yesterday and it´s perfect till now. But on every flight I made I had the problem that I found it very hard to slow down the plane. I´m somehow experienced with these kinds of FMC´s through flying the old ones in FS9 exesively but now i´ve come across something I don´t know any further:Every flight I made so far I had to make an go arround because every time I was way to high and too fast. I´m just back from an 700 MN hop to Juneau. I flew on FL360 and shortly before descent I resetted the MCP to 2500ft. The plane perfectly descended with 330 kts to arround 15.000ft when I took control over the speed management and changed the speed via the "Speed INTV" button to 300 kts while AP and LNAV and VNAV were enaged. That worked like a charm and we descended further. At arround 12.000ft the automatic kicked in and we slowed town to 240 kts. Well, we tried to slow down but in fact it didn´t work. Although the VS was near to zero the engines were at arround 50% N1 and also the help of the braking flaps nothing changed and the message "Unable to achieve VNAV Path" came up. I didn´t see that we were loosing speed at all I had set an target altitude of 4000 ft to the FAP but in fact I was arround 8000ft high when I overflew this point. If my memory treat me right this was alot easier to do in the old ones.So did I do something wrong or is that real world behaviour that the plane takes very long to slow down?

Use a cost index around 30. Fill in your DES FORECAST page properly, i. e. with wind information and if/from what level on you're be using anti ice, otherwise you'll have a hard time if you're facing a stiff tailwind during descent.For me, the FMC appears to calculate the decel points and the whole descent a little too tight, hence I usually put in some more tailwind than there actually is. Plus, at about FL200 I switch from VNAV DES to V/S and do a steeper descent to let the NGX level on FL100 (or 10.000ft, depending where you are) for a while to allow her bleed off speed. Once decelerated, I continue descent.

He can use each CI you want, but if e is having the idle issue, no CI will save him from having the slow down problem as the engine will run too fast at idle.

And as a confirmation, the VNAV PTH descent is made by commanding RETARD ot trottles and then ARM during the descent.So IDLE is the only variable in this case.FMC knows the aircraft data and the winds you put into it, it will never give you an impossible descent path unless somethhing is out of is control (wrong forecast or wrong idle).

The real world behavior is indeed that its a very slippery plane and it doesnt like to slow down while descending. You need to carefully manage your energy during descends. Also a descent at 330kts seems to be at an excessively high speed!

thats bull. I've flown many times on the B737 and 738 and only rarely do they actually use the spoilers. if they do, its only for a short period. I'm having to descend with spoilers ALL the time and still end up fast. The problem I find with using the FMC calculations is that it puts you at 240 kts at about 10 nm or so from the threshold - how the heck are we supposed to lose 100 kts in 10 nm? mind you this is at 2500 ft so we still have to descend (thereby trading alt for spd).I still reckon something's not right with this bird re slowing down. yes I know its a 'slippery' bird but friggin hell, if that were the case, we'd be descending about 200nm out in order to maintain the correct speed right?

thats bull. I've flown many times on the B737 and 738 and only rarely do they actually use the spoilers. if they do, its only for a short period. I'm having to descend with spoilers ALL the time and still end up fast. The problem I find with using the FMC calculations is that it puts you at 240 kts at about 10 nm or so from the threshold - how the heck are we supposed to lose 100 kts in 10 nm? mind you this is at 2500 ft so we still have to descend (thereby trading alt for spd).I still reckon something's not right with this bird re slowing down. yes I know its a 'slippery' bird but friggin hell, if that were the case, we'd be descending about 200nm out in order to maintain the correct speed right?

It's not bull. Read the thread - you're doing something wrong, be it idle thrust set high or missmanaging the descent.