What Cost index are you using B737NG?

[Jinkster]

Just as a matter of interest, what cost index are you all using?

Our airline states 4 for all routes.

[PT6A]

For many airlines depends on the flight.... My company this changes from flight plan to flight plan.....

[Denti]

Will be changed for every flight, but usually somewhere between 10 and 13, highspeed OFPs at 200 (usually used to arrive before night curfew), we're supposed to change it to 8 if we're early.

[de facto]

The airline im working for has a fixed Ci which is close to LRC...guess fuel still very cheap for them.:cool:

[Tailstrike737]

We're using 8-9.

[Denti]

Just wonder, do you use the CI (ECON) descent speeds? Which would be below 250 for CI below 10.

[STBYRUD]

8/9, ECON DES unless otherwise requested by ATC or flight delayed...

[decurion]

A Boeing survey showed that for the B737NG values of CI in the range of 10-30 are often used. Note that a CI=0 equals MRC. LRC is roughly around a CI of 35 on the B737NG. The actual, optimum CI can differ between airlines and routes. If you have a lot of connecting passengers, you might be better of flying at a higher CI than when you don’t have any connecting passengers on board for the same route/aircraft.

I noticed that you (Jinkster (http://www.pprune.org/members/51020-jinkster)) are using a low CI at your airline. Flying at low cost indices can result in speed instabilities. Perhaps you have experienced a lot of movement of the AT when flying at this low CI? Note that not every airline reports these problems when flying at low CIs however. Flying fixed cost indices on all routes is not always the best thing to do either.

Boeing has written a number of interesting articles on this topic. See for instance:

http://boeing.com/commercial/aeromagazine/articles/qtr_2_07/AERO_Q207_article5.pdf

[Johnny Tightlips]

We use 30 for every flight giving us a record breaking speed of 273 KTS in the descent. However most of us ignore it and fly 320/.80.

[decurion]

In this time of economic problems, it seems even more important to fly at the correct cost index. The use of constant cost indices throughout the fleet or ignoring indices given in the flight plan doesn’t help getting the costs down. Note that a given cost index (assumed that it has been calculated correctly) ensures that the total cost (sum of fuel cost + cost of time) are minimum.

[captjns]

As I get paid by the minute... I wish we used a CI of 1.

However our range is between 11 to 15 depending on sector length.

Average ECON speed for the NG varies from .77 to .78 at the higher altitudes, or about 5 knots... At the end of the day, not very significant for a 4 hour flight.

There are times during ETOPs operations, we are requested to fly a given and RTA request which throws the CI out the window all together... even though not resulting in much a total fuel burn deviation from the plan.

Bigger aircraft... larger difference however.

[Callsign Kilo]

Cost index surely should change dependent on network, fuel price fluctuations, operational costings and hedging agreements. Personally I believe that our standard cost index is due to our operational department being so understaffed and it's planning equipment being so inept. Besides, ECON speeds are rarely adhered to anyway, so fuel burn figures based on a perceived standard cost index will be largely inaccurate anyway. Maybe I'll punch in CI 500 next time I fly :p

[captjns]

Maybe I'll punch in CI 500 next time I fly http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/tongue.gif

Not if you're not paid by the minute:=:E

[Denti]

Depends how you are payed by the minute. We are payed by the minute, however we are payed by the minute of standard block times which are a bit longer than flown ones. Usually i get payed 20 to 30% more time than i fly. However if i decide to hold for 2 hours and then land at the destination i certainly not going to make a profit, if i divert i get payed actual block time, sooo, hold for 1 hours and then divert :ok:

[piton]

For us it is 11 - been steady for a few years now....

[cosmo kramer]

decurion:
Note that a CI=0 equals MRC.

That's only half the truth. MRC is a fixed speed for a given weight, ECON speed is not.

With a strong headwind ECON (with cost index 0) will fly faster than actual MRC and LRC for that matter. Since we have no representation of actual MRC, the practical application would be LRC.

The reason being, that ECON will take actual wind into consideration whereas LRC doesn't. From practical experience even a Cost Index of more than 10 sometimes give a lower speed than LRC if you have a strong tailwind (FMC deems it more economical to hang around in the tailwind for a little longer and giving us a free ride).

If fuel is critical, I would suggest to compare and consider the options of LRC and ECON CI=0, if headwinds conditions, before deciding on the better option. Being stuck in a strong headwind at LRC may give you less fuel at destination than letting the FMC do it's magic.

Strangely you wont find that information in the FCOM, but in the FCTM under "Cruise Speed Determination":
ECON cruise is a variable speed schedule that is a function of gross weight, cruise altitude, cost index, and headwind component...
..Headwinds increase the ECON CRZ speed. Tailwinds decrease ECON CRZ speed, but not below the zero wind maximum range cruise airspeed.
In the same section you also find the that for NG, wind correction is not applied for LRC:
LRC is a variable speed schedule providing fuel mileage 1% less than the maximum available. The FMC does not apply wind corrections to LRC.
(Strangely it does apply wind corrections to LRC in the classic, thereby not being a "true" LRC according to the definitions).

[de facto]

Jhonny tightlips,
And why would you fly at 320/.80?please explain:suspect glad i aint your fo:rolleyes:

Indeed ci 0 is the way to save the most fuel (MRC) and best L/D for descent however the optimum(maintenance cost/fuel cost) is ci12.

[7p3i7lot]

We use a fixed CI of 20 for our -300/500/700 aircraft. That gives you a descent speed on 266 in the 300/500 and 261 in the -700. We modify the descent speed to meet published arrival or ATC requested descent speeds. Some folks (certainly not I) flt 280/300 knot descents routinely.
We are supposed to be looking at getting leg specific CIs from a computer program based on a variety of factors such as descent winds etc.

[pilotcop]

de facto, please explain....what is so wrong with flying at 320/.80 :rolleyes:

[de facto]

I just dont see the point to fly at those speeds if not to burn more fuel,high descent rates from top of descent( unless you think idle isnt the way to go),increase in cockpit noise and be so much closer to overspeeds condition.

:rolleyes:

[Shrike200]

...but gets the day over faster, and if you're close to FDP limits (ie ops normal), you at least don't have to extend/call out the suckers.

Econ Mach and 300KIAS myself :E

As for CI, 15-28, precalculated by our flight planning software. The higher value is usually for the shorter legs (1hr) vs the lower value for the longer legs (2hrs). I don't query the computer. I just punch in the numbers.

[pilotcop]

idle is the way to go, am at idle in descent at 320knots, same as at 250 knots, it is closer to over speeding yes, however should circumstances require it, i will slow down to 310 knots, that little extra margin keeps everyone happy

[de facto]

Shrike, obviously if your airline has an aircraft planned to fly all day,ie if you get late the last flight of the day is cancelled then yes flying higher speeds makes commercial reason,,,but passengers im sure dont quite enjoy idle descent from high level at 320 kts,quite a descent rate..and fuel burn is highly increased..
If you are early however i decrease the ci to save fuel as a mere 100kgs saved/aircraft/leg in a large fleet makes quite a saving at the end of the year:ok:

[despegue]

De facto,

Many of your claims are more typical of a Microsoft flightsimulator teenage boy than of an experienced airline pilot:rolleyes:

"Closer to the overspeed conditions" are you kidding me?! 320kts. is a good standard of descend speed on NG in stable air.

"uncomfortable for the passengers" My god man, you don't know what you are talking about! It has nil, zippo nada efect on pax. comfort if you transition from level to idle descend when doing it correctly and don't slam the thrust levers etc... it is called airmanship. (but wait, I see your profile does say location China...)

In my company, we do NOT have a fuel policy, we use CI35, but this is to the discretion of the commander...

[de facto]

Despegue, for the overspeeds,it was regarding using .80 in cruise,for the desent rate,from level 400 ,.80 is a high descent rate through the high levels..
Ci 35 aint giving you. 80/320,,,sops is another story.
What is ur issue with my location?:ugh:

[framer]

From practical experience even a Cost Index of more than 10 sometimes give a lower speed than LRC if you have a strong tailwind (FMC deems it more economical to hang around in the tailwind for a little longer and giving us a free ride).


Normally about 30 gives you LRC but quite often you can see that even a ci of 40 or so will be slower than LRC.

Is there a way of fooling the FMC during the set-up to determine your minimum drag Mach no. in the cruise?
I was thinking that putting in you FL and zero wind, and ci 0 might do it. Thoughts?

[de facto]

Despegue,
For some reason i remembered this discussion in my pc sim today..here are my notes..
1.40 min remaining,67t, FL370,M.78 eco.
I enter select M.80/320 in my pc fms and i notice 2 mins decrease in flight time,100kgs less.
Now as a poor airmanship professional i maintain my M.78 as i rather save 100 kgs than 2 mins.
At 65T my indicated speed shows 250kts, barber pole 266kts.
Now selecting M.80 i get 260kts indicated, a mere 6 kts below an overspeed.
During one hour cruise without any turbulence my speed in few occasions increased to 256 kts,which if i had M.80 i would have got into the overspeed.
Do i think the 2 mins save worth that overspeed? i think not.

Now at top of descent i select LVLCHG withm.78 initial rate 3800 ft/min during the first 3000ft then about 3400,speed at on point increase to m.798... In which case if i had M.80 selected i would have been into m.818.. Pretty close
to another overspeed....
Now the cabin rate,,,,shows 1000 ft min, now it may nit be a new NG but still
not so nice for pax,,,,we all know the target is 300..
Now if i had selected m.80 the rate would have obviously been higher..close to 4500 ft/min.
Such rate for me is just not comfortable for me so im sure for the pax neither.

So after 2 close if not overspeeds,tell me how how i would explain to my superior 2overspeeds to gain 2 mins and burn 100 kgs more.

Now please reading a few of your arrogant answers,i suggest you get on with your mighty professionalism and let us discuss our opinions without racist comments.
:ugh:

[de facto]

Framer,

Ci 0 is your best endurand speed in cruise and best L/D for descent.

[Jinkster]

Cost Index of 4 gives 243kts in the descent and about .76 cruise speed.

Painful I know! :{

[framer]

Ci 0 is your best endurand speed in cruise and best L/D for descent.
That is not my understanding de facto.
My understanding is that ci 0 is MRC which is faster than best endurance.
Best endurance is min drag and I would like to know a way of determining what that is while I am loading up the FMC on the ground. One of the reasons I have for this is that any slower and you are 'speed unstable' as you slide down the back of the drag curve. For interest sake I would like to be able to know what it is.
At ths stage I only know that it is slower than MRC (ci 0) .
Could it be determined using the holding page?
Framer

[framer]

Just a slight add on to what I said.
In my FCOM it says that on the HOLD page, down the bottom right where it says "best speed"

Displays computed best holding speed based on present altitude and conditions.
Note: May exceed maximum speed permitted by regulatory agency.

What I want to know is, best for what? Endurance? Avoiding a stall? Getting around the hold quickly? I imagine it is related to endurance but I would like to know if it is min drag for those conditions. ANyone know?

[Ex Douglas Driver]

From the 777 Honeywell FMS Pilot's Guide

BEST SPEED (5R) -- The best speed for the holding pattern for the current altitude and conditions is displayed in 5R. The best speed represents the maximum endurance speed to provide the maximum time aloft.

[de facto]

My mistake, ci0 is by BOEInG MAX RANGE (min fuel burn)for cruise and MAX L/D.
Refer to boeing website...

Maybe this will answer your question:


Vmax endurance = Best glide speed/1.316
Vmax range = Best Glide Speed

Voptimum cruise = (Best Glide Speed) * 1.316

[Sciolistes]

Best endurance is min drag and I would like to know a way of determining what that is while I am loading up the FMC on the ground.
As per the FCTM, as well as the hold page, to all practical purposes the standard clean speed derivation of Vref 40 + 70 (UP speed) would be min drag or close enough. +10-20 kts probably would make no significant difference due to, as I understand these things, a very flat drag curve. Obviously any slower and flap is required so not applicable.

As the FCTM states, another consideration, is that at altitude, UP speed is less than the min manoeuver margin, so the speed would have to bumped up a bit, Vref 40 + 100 is recommended.

I suppose this can be checked if one actually ends up in the hold, select UP speed and note the engine params, then the same for best hold speed. See if there is any measurable difference.

[framer]

Thanks, I am aware of the Flap40 +100 approximation. Ours says;


Recommended holding speeds can be approximated by using the following
guidance until more accurate speeds are obtained from the QRH:
• flaps up manoeuvring speed approximates minimum fuel burn speed and
may be used at low altitudes
• above FL250, use VREF 40 + 100kt to provide adequate buffet margin.

I am interested that you refer to a flat drag curve. Have you ever seen one for the NG? I haven't and would really like to get my hands on one.
So the best I've got now is that Vref40 +100 is close to min drag, and ci 0 = MRC. Thats ok I guess but I would like a more definate way of determining min drag (max endurance).
Cheers.

[Tailstrike737]

CI of 8-9 will give you a descent speed of around 249kts :{

[topgun b737]

we use cost index 13 , 14 or 15. it depends on the flight.

[framer]

but thrust me the wings will NOT fall off.



My wings would if you did that to me:eek:

[de facto]

IRISH PiLOT!
You have a big mouth for someone who was still building hours 2 years ago:rolleyes:
Yes it is an automatic controller but please have a read on how it works!!!
I was talking about m.80 in cruise and initial idle descent.in my airline if you get an overspeed,you are scheduled in for a meeting.....rather avoid that and get a fuel bonus..but i guess you wouldnt get any of the two as you are obviously a low hour f/o and fly for a low cost..
Believe im not scared of overspeed neither was i when i was flying turboprops close to its limits quite often.(cargo single pilot sa227s) but there were no qars involved nor passengers,while you were still In high school.
Overspeed IS an exceedance just like a flap overspeed...do you think its ok to select flaps 1 at 245kts?would you say its also ok having to use your speedbrakes in case you get a flap overspeed right because of your planning:ugh:
Do you write your overspeed in the techlog after landing?obviously not,you wouldnt know where to look for one.

I save time on the ground and try to get shorter routings and optimum levels to save time...not flying at m.080/320.
For your info im paid extra for flight time,true,but also for fuel saving,fuel saving gives me a nice average of 500 eur net/month.:E

Concerning your pc sim 5000 hours thing,its a childish remark for a so called pilot,by the way i never played these games...
Fly at speeds you like and ill do the same.Enjoy the overspeeds with your speed brakes at high levels while i enjoy my coffee at a fuel economic speed.:rolleyes:

[framer]

For your info im paid extra for flight time,true,but also for fuel saving,fuel saving gives me a nice average of 500 eur net/month.http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/evil.gif


Wow....I didn't realise some companies still do this.
How do you find it? Does it have any impact on your decision making re go- rounds ?

[Flogged Horse]

So what is the airline saving if they are paying their pilots 500 Euro/month. Last time I checked there are usually more pilots then jets. I'm not against any pilots getting paid more but this doesn't make much sense unless I have missed something.

FH

[captjns]

Reference to passengers not noticing the difference between a 310 to 320 speed decent versus a path descent on a cost index of 11 (circa 250 kts.) is not true. The noise level at the higher speeds is noticeably higher and pitch angle is quite lower (about - 2 1/2 degrees) versus a virtually level nose attitude with a calmer rate of descent.

Also, the cabin crew will appreciate that slower rate of descent when negotiating those galley carts up and down the aisles during stowage for landing. Ever experience a galley cart slamming into the cockpit door? I witnessed it whilst sitting the back of the jet during a high speed descent. Luckily the galley cart went straight for the cockpit door and did not careen into any of the sponsors who make our paychecks possible.

Anyway at the end of the day is a two minute savings in flight time really worth the effort of causing discomfort and a possible difficult working environment for those behind the cockpit?

As I get paid by the minute, I have no great need to push my jet to it’s designed limits… that’s what the test pilots get paid for. Anyway… food for thought.

[de facto]

Framer,
Joining the rank of immature remarks too?please...:hmm:
Captj,
True, i really started to think than i was the only one feeling the effect of those high rates of descent..but seems like a few testosterone filled pilots with latest noise canceling headsets tend to forget that the people behind are those paying their wages and that their passengers dont fly regularly nor average 20 year of age.
Concerning the fuel saving bonus,yes,some airlines do pay you based on your monthly fuel saving,everybody wins...:ok:

[framer]

Joining the rank of immature remarks too?please...http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/yeees.gif


No. No not at all. I would genuinely like to know how you find it.
It is generally thought that it effects some pilots motivation in a negative way re safety. The thought is that when presented with two options and the safest one uses more fuel, that it makes it that much harder for the pilot to make the correct choice. Go-arounds are a good example. So is diverting around weather. Most pilots are fairly determined and don't like to give up easily, they also don't like changing the plan, thats why so many approaches are continued around the world that were unstable at 500ft and a go around should have been conducted. Now add to our already feeble decision making abilities the thought of losing some of that precious 500 euro, and the correct decision becomes less likely.
I was anting to know how you combat this, and how other pilots in your airline combat it. That is all, no need for silly faces.
Framer.

[framer]

De Facto, To demonstrate that my query was genuine and not in any way facetious,(or immature as you said), I have cut and paste from the trial of a Garuda Airlines Captain who was charged with the deaths of 21 people.


Komar's trial for criminal negligence over the deaths of 21 people in the crash, including five Australians, begins today. He has never spoken publicly about the Boeing 737's descent, but his police interrogation report, which is central to the case, has been obtained by Herald.


Under questioning, Komar said there had been arguments with his co-pilot during the landing. He admitted the plane touched down at an unsafe speed.


He said he was concerned about conserving fuel -

Komar said he compromised with his co-pilot, Gagam Rahman, on the level of flaps the plane was using on descent because "by using a flap of 30 degrees the usage of fuel was relatively not much". Garuda had introduced large bonuses for conserving fuel shortly before last year's accident.


It was my understanding that the practice of rewarding pilots financially for fuel savings was understood to be a Human Factors disaster and that no reputeable airline did so anymore. It is akin to 'dive and drive' techniques v's the now accepted constant decent approaches, in that it is a recognised threat to safety.
That was my understanding. Feel free to correct me, I am always open to new learnings.
Framer

[de facto]

Framer,
As far as i am concerned,if a go around or diversion is necessary i will do so.
Fuel saving in my mind has no effect on my judgement of safety.
If diversion is made,extra fuel burn is not accounted anyway...
500 euro is good but really pocket change compared to our paycheck.
I rarely take extra fuel as the minimum fuel on flight plan is already quite generous compared to low cost i flew for in europe,if the crew decides to add fuel no question are asked,at least personnaly i never got questionned.

My airline takes safety very seriously,and having done 3 diversions due to airport overcapacity,and a go around, i have never been asked any question for the reason of such action or why a go around was performed.
Our sops dictate 1000 ft to be fully stable imc and vmc, if not a go around must be performed.
Concerning flying around weather,i am very conservative and can say i never got into a dangerous situation nor stroke by lightning,as you may have noticed about the speed issue, i like confort as much as the passengers.
However 90 percent of time, fuel saving is possible and i will do all i can to do so,within a confortable safety net.
Crews are very closely monitored and cowboys get spoted very quickly and put back into place.
So yes im sure this bonus has no impact on safety decision within my airline.

[Johnny Tightlips]

This thread has drifted miles of course and that is partly my fault. Let me explain why I fly high speed all the time. I work for a (in)famous European airline that has zero respect for me or any of my colleagues. I am based in a awful base in southern Europe where the company regularly leaves the block times at least 10 minutes shy of what they should be due to a 20 minute taxi that they don't and won't take into account. As I get paid by the scheduled block hour I have no intention whatsoever of flying ECON speeds and get shafted once again by these useless shower of clowns. I am a FO and I always ask the skipper first if he is ECON or high speed. If he says ECON I respect him and do it his way but I would say 80% tell me to fly as fast as I want as long as I don't break anythinghttp://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/thumbs.gif I have even had some Captains bark at me for NOT doing 330/.81. But then again if we were paid by the actual time and the airline treated us with a bit of respect we would gladly respect their fuel policy and do that wonderful 273 KTS descenthttp://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/smile.gif

[framer]

Defacto,thanks for the answer. I have another question, is FOQA part of the reason your airline can operate this policy without influencing the decision making of the pilots? Cheers and thanks for the apology ;)

Jonnytighty, Your airline sounds terrible man. I can't understand management like that as it's such a false economy. It would be much cheaper for them to pay an extra 20 mins block time and not have a p1ssed off pilot group.

[de facto]

Framer,
Please accept i withdraw my initial remark.
Now, Pilots are humans and all have different views on the matter(foqa),however flying at .081/330 just because one doesnt get paid for the extra time doesnt show AiRMANShIP(a word despegue seems quite fund of)nor a great sense of professionalism or maturity.

Im sorry johnny has to endure this on a daily basis but i hope when he will eventuallly upgrade he wont follow such way of thinking.

[Spitfire.]

Hi chaps. What Cost Index is Qantas using for it's 737-800's? Would love an answer. You can Private message me, I promise I wont tell anyone if you don't want me to. Thanks.

[pilot999]

Johhny tight lips :

Well I am surprised you are still here, but probaly won't be for too long. People likes yourself usually have little backbone and are all mouth Who often fail their annual line check and command upgrades. and rightfully so as you seem to show little airmanshipn or professionalism. With your attitude little Sympathy simpify can be felt towards yourself.

[lostintransit]

300kts+ burns more fuel than 250kts, for the reason that less time is spent at idle thrust. You might not feel that the small fuel saving is worth it but your employer might disagree and it's simply poor practise. Think of the extra fuel consumed on a cumulative basis.

I bang my head against the wall (metaphorically, of course) when I see guys quite correctly flying a variable, CI-generated, econ speed throughout the cruise...yet dogmatically sticking to a fixed (and invariably higher) speed in the descent. It burns extra fuel, may save you two minutes at best and is weirdly inconsistent; just fly econ speed unless ATC says otherwise...

[pilot999]

It allways amazes me how many First officers want to fly on the longer routes from the Canaries at .80/.81 ,only to find out when told NO that the time saved is only Eight minutes versus an extra Ton of fuel burnt. No thanlks !!!!!!!! the Cruise is for reading the Papers and magazines not waiting for a tech log entry for Airspeed exceedence, Dont even get me going on energy management for those that want to descend at .80/.81 into a jetstream:ugh:

[mike734]

The problem with a .80/320 decent is that if the winds are not as forecast or ATC changes you speed or route (like cutting a corner) you will find yourself high and the jet will nose over to capture the path. At .80/320 you will find yourself out of Vnav path in short order struggling to get back on the path in order to make the crossing restriction.

I see no reason to plan a high speed decent. If you plan a .78/280 decent The Vnav will plan an earlier decent path. You can push up the power if you desire and fly .80/320.

We use a CI of anywhere from 12 to 99 depending on my dispatchers plan. I routinely override the cruise speed from ECON to LRC to get a higher cruise mach at lower CI'es. For example, with a CI of 12 a typical cruise mach is .76. If I manually select LRC the cruise will pick up to .79. I'm paid by the minute but don't like to spend one more minute at work than necessary.

[framer]

I routinely override the cruise speed from ECON to LRC to get a higher cruise mach at lower CI'es. For example, with a CI of 12 a typical cruise mach is .76. If I manually select LRC the cruise will pick up to .79.
Personally I don't really get that. The airline obviously has spent time and money organising a system that determines the c i they want you to use on that particular sector. This will be based on their labour costs and their engineering costs and their fuel costs. So why don't you use it? If your airline does 180 average length sectors a week, a 100kg fuel saving on each flight is 18 tonnes a week , 936 tonnes a year. Thats a lot of gas.
Determining cost indexes seems quite complicated, on one flight MRC (c i zero and min fuel burn) can be .745 with a LRC of .778, and the next flight MRC can be .77 with a LRC of .79
On the latter even c i 60 will be slower than LRC.
If you aren't late I can't see any good reason to fly faster than the c i that the company has spent time and money determining.
Is I'm paid by the minute but don't like to spend one more minute at work than necessary. your only reason or is there something else?

[captjns]

At the end of the day... what's to be gained by flying at .80 and 320 Kts on descent? Noise and discomfort the folks in the back of the jet. Do you really save that much time? No.
Now if you're talking about the 727... different story. The 727 can easily lope along at .875 without breaking a sweat... Time will be saved over .78 cruise with quite a fuel burn penalty. But flying cargo back in the day cost was not the motivation... on time performance was.

I'm no boy scout by any means... however, I'm always thinking about how much extra gas I can keep in the tanks if there's a bit of extra holding at my destination regardless of weather conditions.

[pilot999]

Thats exactly it. having the fuel in the tanks at the destination is far better than saving Six minutes over 4 hours.

[B737NG]

Previously the company used CI 30 on all B737 flights and a fixed CI in other fleet types as well. Fleet Manager - Chief Pilot did not understand that the CI should vary on a daily base. "Someone" else decided not to purchase that with the planning software. All CFP´s where made with a fixed CI 30. Sadly but true that was mainly because of the culture there.

Descend planning was .78/280 and changed in the FMC descend page.

In the present outfit we use diffrent CI´s on all Fleet and for each flight a new calculated one, that is reflected on the CFP and inserted into the FMC, the climb descend speed is also changed manualy according the CFP.

That speaks for A320, B737NG and B777´s as I have seen it lately.

Fly safe and land happy

NG

[KAG]

De facto: I save time on the ground and try to get shorter routings and optimum levels to save time...not flying at m.080/320.
Seems smart to me.

Saving 1 minute on a flight but monitoring the speed like crazy when flying at mach 0.80, no thanks. it's not worse it.

Yes there is a cost index, but .76 and 280 are speeds that respect safety (turbulence), and like to use them.

However at high speed, the cockpit noise difference is more important than in the cabin... Smooth transition is the key, hard to beleive the speed is a confort factor when no turbulence...

[bubbers44]

Simple, if you are a comuter trying to make a connection home cost index should always be zero. Otherwise do what ever the company wants. Quite simple actually.

[eagerbeaver1]

We used 30, I found myself rarely adjusting the speeds for my own preference (Iworked for that Irish airline).

I did what needed to be done, for example If i knew the easyjet ten miles ahead was going to the same airport as us then I would overtake. This was not too difficult as those chaps often cruised at .76 and once .74!

I tried to beat the traffic at the end of the night which often worked and enabled ATC to give me us the fab shortcut which saved approximately 600 to almost 1000kgs!

So to answer fly the company CI and adjust your technique appropriately for the given circumstances.

De Facto - You have a brain - use it. You don't have to stick rigidly to SOP's, you are deliberatley reducing your choices unreasonably.

[de facto]

EAGERBEAVEr1:
[QUOTE]De Facto - You have a brain - use it. You don't have to stick rigidly to SOP's, you are deliberatley reducing your choices unreasonably.""

May i ask you where in my statements did you get that i was rigidly following my sops?
Concerning my brain i do use it ,thank you very much,maybe you should read,assimilate then type:ooh:

[eagerbeaver1]

That is the perception I got from your posts. Anyhow, I haven't a clue who you are, you could be some total muppet.

[de facto]

Eagerbeaver1,

Insult is not a sign of intelligence especially for one who does not take time to read and whose perception is oviously wrong.
See even a muppet can do that:
Ryan air?huh? I see they trained you well,they will really miss your style:ugh:

Now i suggest you adjust your attitude in your new position or your 'experienced captains' will swiftly put you back in place.
Another assumption/perception:oxford graduate before ryan air?

[framer]

There are probably as many different opinions on this as there are Captains. The trick, IMO, is to base that opinion on a bit of knowledge rather than just inheriting an opinion off your first pilot group, or influential Captain etc.
The fact that we are discussing this and sharing info is a good start.
I think it comes down to a simple choice;
A) Shall I save an apparently small amount of fuel knowing that across the fleet, over the financial year, it will add a lot to the profitability of the company. or;
B) Shall I look after No.1 and who cares about the company they don't care about me, I want to get there quick.
A lot of pilots think that flying LRC will see them arriving overhead the field with the most gas in tanks. Thats a bit scary but true.
A lot of pilots don't know that ECON accounts for wind but LRC does not.
The more we can analyse the opinions of our peers with the mindset that we might learn something, the better.
My 2cents.
Framer

[eagerbeaver1]

So what you saying?

[framer]

It was a veiled attempt to stop you two from questioning each others intellect, abilities, and flying pedigree and return the thread to a more factual/technical tone.

[framer]

After a quick think about it I think that
analyse the opinions of our peers with the mindset that we might learn something, the better.
was the main thing I was trying to express.

[max payload]

Take the time to read all 4 pages of this thread and one might be forgiven for thinking that today's flight crews don't have a clue about things that they're supposed to be knowledgeable about.
And childishly keep bickering among themselves about it, too.

I won't comment on remarks with respect to each others perceived airmanship (apparently in short supply), let alone common employee decency (get paid- do the job as requested and to the best ability).
Do, however, feel free to continue to amuse the rest of us.

+++

Max Endurance equals Min Fuel Burn.
An aircraft will be able to stay aloft the longest at Min Drag Speed, not Best L/D.
Best L/D will get you the most bang for your fuel bucks in terms of range, not endurance. Two different things entirely.
Holding should be flown at Min Drag speed (clean wing!) for the specific conditions.

+++

It is said that MRC equals CI=0. This is not true, and a case of apples & pears.
ECON speeds derived from programming CI values into the FMS/FMC result from taking into consideration the impact of winds and temperatures on specific range, resulting in optimized, minimum COST speeds for the given and expected circumstances compared to the more coarse (corrected) fixed Mach flying.

LRC burns 1% more than MRC, but is similarly less efficient compared to flying at CI-managed ECON speeds, again, because of the actual atmosphere versus still air conditions.
Provided that CI values are correctly derived & set, cruising a fixed Mach regime will always COST more than CI-managed cruise. I've seen up to 15% more Specific Range efficiency at low levels and high headwinds.
CI-managed cruise makes you fly faster in a headwind, and fly slower with a tailwind. For those of you with gliding experience- sounds familiar?

Question is- who pays for that increased cost when ignorance decides that he or she knows better (often), or that the boffins don't have a clue (equally often), or simply shows a case of GetHomeItis (as stated in this thread)?

On the other hand, determining CI values is an art.

The simple version of CI calculation is focused on the cost of flying an additional minute; what Variable Time Cost do I incur compared to what increased Fuel Cost.
This is a coarse approximation, but since most airlines don't have a clue about Variable versus Fixed Costs of Time, or even how to accurately determine these costs, this becomes the preferred method, sometimes even using benchmark numbers found elsewhere in a (cost-wise) different operation.

(Variable) Cost of Time doesn't change often (contract negotiations, change of MRO), however, Cost of Fuel does.. on a weekly basis, even per city pair.
Compared to 12 months ago the average fuel price is 30% higher and so, consequently, your CI values should be about 30% lower than last year. Are they?

The more complex method takes into consideration the overall organic network effect of slowing down or speeding up the fleet (As CI values approach the lower 10s, schedules get stretched upwards to accommodate the slower flying, subsequently requiring additional flight crews to fill those higher block times, in turn creating additional network cost). City-pair specific fuel price deltas (sector-specific CI values) and additionally, specific aircraft operating limitations by only allowing a certain band of ECON speeds for climb, cruise and descent (we want to avoid having aircraft ECONning at such low speeds and high alphas that a stall comes close), and of course tail-specific performance degradation factors.

Lastly, ATC still doesn't get it after all these years, even though most everybody is cruising sloooooooowly nowadays.
Off-optimum levels, lousy vectoring, pushing speeds, bad sequencing, no clue about individual aircraft performance, all that jazz.

So What Is Wisdom?
Me thinks that the one who has the correct answer can sell a very nice tool.

Now, continue ze bickering, I find it amusing :E

Max :ok: