Load & Trim sheet / Dry Operating Index

[Superfly]

Hello my fellow Ppruners,

Can any one please give me some help/info about load/trim sheets >>>>>>

How do you determine the DRY Operating Index ? I know there is a relation with the number of crew but I can't work it out....

Thanks for your help

Happy landings, Superfly

[PiperChauffeur]

The Dry operating weight is the Basic Weight plus crew and catering, or in other words the takeoffweight minus payload and fuel (and ballast if any).
This means that DOI/DOW on an outbound charterflt differs from the homebound, if returncatering is carried onboard the first flt. It also means that DOI/DOW varies with crew. You will find the actual DOW/DOI in your AFM.
DOI is usually determined by finding the weight on the different wheels together with the wheel distance from the AC most forward point (reference datum). Or in other words, you find the arm and moment for the wheels. Now you can calculate the DOI. This is always done by the manufacturer, although operators check it. Weights may vary quite a bit between AC of same type and age. Operators have to make a mass/balance check when installing new eqipment in the AC.

I dont remember the excact intervals, but operators do have to make a mass/balance check every 4 or 5 years.

Was this the inf you wanted?

PC

[Superfly]

Piperchauffeur,

Thanks for the info, Yes I think this is it. I'm just a bit worried as I'm preparing the Mass&Balance subject for the JAA ATPL and can't find the Dry Operating Index in the CAP 696 booklet. It is just given as being equal to 45 on the example load and trim sheet.....
Is this info usually given in the Operating handbook of the A/C or Fleet Information ? Or is there a means of calculating it ??

Cheers, Superfly

[Icarus]

Dry Operating Wt is the basic weight of the aircraft plus OPerational Items such as Crew, Crew Baggage, flight equipment, pantry.
The DOI is the balance condition at the state of Dry operating weight.
Usually in terms of %MAC but indices can be used to make life easier.

Indices are calculated as follows :-

Dry Operating Index = [(Sta - Ref. Sta)/C]+ K

Where,
Sta = The station (in or m)where the C of G is calculated to be after adding all components.
Ref Sta = Reference Station/Axis around which all index values are calculated (in manufactures manual.
C= Constant used as a denominator to convert moment values into index values.(variable by carrier).
K = Constant used to avoid negative index figures. (variable by carrier).

[This message has been edited by Icarus (edited 28 February 2001).]

[Superfly]

That's it, I see the complete picture now !!!! many thanks Icarus :)

Superfly

[Icarus]

If you think you need more or have similar questions just mail me, no problem.

[Superfly]

I'll keep your e-mail address in a safe place then !

This performance subject is more than interesting but can be a bugger too !! :)

Happy landings, Superfly