ZFW CG

[Trevelyan1975]

Hi...

I work as a Load Control. We have A330/A340 's in our fleet. Our management has now introduced << CG Planning Percentage within the ideal range ( Trim ) >>
This is in a chart format where each flight is analyzed and a report generated with stats end of each month as to how the aircraft's have been loaded during that particular month.

May I know if an aircraft loaded with AFT heavy would really contribute on fuel saving.

My understanding is that, an air plane having a trim tank will always steady the A/C to its best pitch and thereby do its part of optimizing fuel saving.

Appreciate you expert comments on this please ?

Thanks !

[plhought]

To really simplify it, aircraft with an aft C of G reduce the amount of loading on the horizontal stabilizer, reducing the amount of work (basically up-side down lift relative to the wings), reducing the induced drag, reducing fuel.

If you look at a profile of a horizontal stab, you'll see it's an upside-down wing.

Unless you're flying Concorde then you don't have a Stab ! 😃

An aft C of G certainly results in fuel savings. There's publications regarding this for many aircraft types. If you require I can provide examples for an Avro RJ and Dash-8s. Fuel savings ranges from around .5% to up to 3-4% on longer legs.

The benefits have to be weighed against aircraft controllability and pilot preference every once a while. In my case, our pilots get a little crotchety if they have to bring in a Q400 into a 4000 ft strip and the thing's loaded to the t***s way aft.

Of course, one should always have the aircraft loaded within it's C of G envelope, allowing for changes due to fuel burn and normal allowances etc etc...

[Trevelyan1975]

Hi...

My company says that as Load Controllers we need to focus on TAKE OFF CG instead of ZERO FUEL WEIGHT CG. Not sure if this is correct. They want us to achieve an AFT CG based on the TAKEOFF WEIGHT.Appreciate if anyone could elaborate on this please ? Thanks !

[de facto]

Answer is above...CG moves forward or aft initially based on your fuel tanks position.
So if your CG moved foward during that flight then your company would like you to take this fact into account when planning the loading.