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-   -   Fuel burn in climb (https://www.pprune.org/tech-log/330363-fuel-burn-climb.html)

GSLOC 8th June 2008 15:43

Fuel burn in climb
 
Talking about boeing 7' series (737, 767, 747).
I looked at their AOM's and it seem that there is no data on fuel burn in climb (only N1 in climb). All there is - for long range cruise control perfomance (http://img359.imageshack.us/img359/7...fomancevl0.jpg). So how climb burn is calculated, especially with taking gross weight into account?

GSLOC 12th June 2008 16:59

Any ideas anyone?

Check Airman 12th June 2008 17:20

Fuel burn will be changing all the way up, so it's difficult to give a fuel flow number. However there are tables that will give total fuel consumption for the climb phase.

GSLOC 12th June 2008 17:58

Where these tables can be found? Neither AOM, nor QRH have them

B737Capt 12th June 2008 23:57

Boeing Flight Planning & Performance Manuel (http://www.b737.org.uk/perf_climb.gif)

Airbus FCOM 2 & 3

:cool::cool:

GSLOC 13th June 2008 00:57

Thank you, that's exactly what i need (at least for 737)! However iam steel confused why it is not published in aom or other related document like qrh or flight crew training manual.

18-Wheeler 13th June 2008 02:01

747 Classic is close enough to ten tonnes from takeoff to top of climb. AS mentioned, the burn varies quite a lot from ground to cruise. Something like 33 tonnes/hr on takeoff up to 13 tonnes/hr for a heavy cruise.

enicalyth 13th June 2008 06:45

I can supply
 
I have a set of "norms" for the 744. I can distill these into a spreasheet quite easily.

For the a/c I know a look out the window, figures from the loadsheet and put the two together. Bingo. Yes, you do need some kind of ready reckoner in case one day the gremlin strikes.

I don't need to rehearse the usual caveats. If this will do either post or drop me a line.

GSLOC 13th June 2008 06:47


747 Classic is close enough to ten tonnes from takeoff to top of climb. AS mentioned, the burn varies quite a lot from ground to cruise. Something like 33 tonnes/hr on takeoff up to 13 tonnes/hr for a heavy cruise.
Yes, that's why iam asking. I need exact figures.

enicalyth 14th June 2008 12:58

I think you are missing something
 
Exact figures? They don't exist till you've flown it but estimates and rules of thumb can be helpful.

Have a word with your engineering ops dept and they'll explain.

Figures for what BRW, Initial Climb to where, Temp?? Here is one variant of the 744. No noise restrictions, radical departure. [Doesn't happen, EVER].

Anyway try this. Climb to FL330. 'Valid' for BRW 340->400T.

Distance ~ (0.6BRW-110) ISA; (0.6BRW-105) ISA+10; (1.1BRW-245) ISA+20
Time~ (0.1BRW-20) ISA; (0.1BRW-19) ISA+10; (0.15BRW-30) ISA+20
Fuel~ (35BRW-5600) ISA; (35BRW-5200) ISA+10; (50BRW-9500) ISA+20

In case I have mistyped a first guess goes as follows. Say BRW = 386T. Estimates are then 122nm, 127nm, 180nm to T/C at FL330 at ISA, ISA+10, ISA+20 respectively.

Similarly time 19, 20, 28 mins respectively.

Fuel 7910kg, 8310kg, 9800kg which you can work out as being 2.05%, 2.15%, 2.54% of BRW respectively.

In general the smaller the aircraft the higher the %age BRW is burnt in climb but the gross figure naturally is smaller.


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