Another A320 Q. Step climb....

[CaptSensible]

What's your favourite method for calculating the point when you can step climb...e.g. if weight restricted to FL330, and hoping to go to FL370.

[CHAPARRAL]

FCOM 2.05.20 pg. 1 states "the optimum weight to perform a 4000 ft step climb is the weight for which this higher level can be reached".
Personally I use a step climb when I get the optimum level 1000 ft below of the altitude to step for in order to prevent a poor climb gradient and to have better buffet margin.

[CaptSensible]

But what method do you use to calculate the point further down-route where you expect to be able to make such a climb? For instance, if you are at FL330 and ATC ask you when you can accept FL370, how do you calculate that point?

[Grandad Flyer]

Well. You know at what weight you can reach that altitude (its usually around landing weight) by checking in the QRH.
You know how much fuel you are burning per hour.
So you can work out how long it will take you to be at that weight.
That's it.

[CaptSensible]

Hur hur hur....not a fan then?

[CaptSensible]

Seriously though, can't the 'magic box' produce something better?

[Silky]

As a magic man myself I use the afore mentioned technique and then check the "box" for a corresponding weight. No where in the FMGS will it tell you when to climb. :) :) :)

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Gravity always wins....

[VH_KAM]

Ask HPSOV !!! :)

[m&v]

Check'optimum'alt on Prog page.See what it says is Opt' with your present weight/temp'
Select 'Airspeed'modify your cost index(go lower to 10,from 30)in 'perf' page.Rechck your 'Opt' on prog page-to see if it improves your 'opt' with lower C/I...If it don't improve-stay where you are!! If it improves with the lower C/I,your in the ballpark.I've been in the temp' squease too many times to Just go,without any other guides.

[CaptSensible]

Thanks all! :)

[Silky]

posted 10 December 2000 02:26
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Check'optimum'alt on Prog page.See what it says is Opt' with your present weight/temp'
Select 'Airspeed'modify your cost index(go lower to 10,from 30)in 'perf' page.Rechck your 'Opt' on prog page-to see if it improves your 'opt' with lower C/I...If it don't improve-stay where you are!! If it improves with the lower C/I,your in the ballpark.I've been in the temp' squease too many times to Just go,without any other guides.

The real facts are that ***** in ***** out.... the adjusting of your cost index is only as effective as the other elements which the "BOX" use to calc the opt and rec max. If one of the others is out...... i.e. tropopause, cruise temp or assumed weight then it aint worth S***e. So I again point to the green dot, if this calcs the aircraft weight to be heigher than the crew/load sheet weight then this is the weight the aircraft responds to.(pfd displayed limits VLS MMO)So by adjusting the CI in this case you get a better looking picture than is actually the case, in other words you aint going to get up there :) :) :)


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Gravity always wins....

[m&v]

Silky: You may be very correct in your assessment, for using the "green Dot"speed,as an index of true weight of the aircraft for alt' changes.I've simply found that with the 'Actual'info at hand:temp,prog,perf',and variable cost index,one can get a better idea of the feasability of Climbing,or not(Its worked for me for eight years),
Cheers(up the Lord Darcy LBA)

[thermostat]

Here is a rule of thumb I use on the A320;
Lets say we're at FL310 and want to climb to FL350. Take a look at the Max Alt. In this example it reads 344 so we would have to wait for it to read 350 before climbing. The difference in this case is 600 ft. For each 100 feet we must wait 8 mins and lose 400kg of fuel (or weight). So in this example we would have to wait 48 mins (6x8) and burn approx 2400 kg (400x6)of fuel.

[Silky]

Being a new boy of 6 years TRI/SFI on type I may just not be up to speed, but in the areas I have operated the A320 (North America-central-south, africa ,middle east and far east) I have found that you cannot always rely on the info handed to you by the red cap.... I wonder have you ever noticed the "check gross weight message", common occurence in these places. :) :) :)

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Gravity always wins....

[This message has been edited by Silky (edited 12 December 2000).]

[CaptSensible]

Thermostat, I like that one. I'll try it!