Weight and balance & AHM 560

[drumex]

Hi there.

I'm looking at the AHM 560 for an A330-200. The carrier has opted to fill out the C5 sheet such that they have two set of tables for MTOW values; one for takeoff, one for inflight.

Could someone kindly explain to me what the difference is?

I should mention that I'm not a load controller or deal with aircraft directly (apart from flying gliders as a hobby). I'm a software developer though I'm not completely new to W&B. I have re-written a W&B system (sans calculation engine) for a long-standing company, so I am familiar with the subject to a certain degree. I'm developing a new software that also deals with the subject of weight and balance and for that, I need to understand the AHM 560 documents more in detail. There may be other questions that follow. :)

Thanks.

Moss

[Icarus]

It's just another envelope to consider.

Practically translated, in your 'application' you will have to look at the 'space' between your TOW (Take Off Weight) CG and your LAW (Landing Weight) CG and ensure the CG does not go outside of the inflight envelope. You would approach that by following the CG movement as fuel is burned.

Make the assuption that fuel is used in the reverse of that loaded.

[drumex]

Thanks for your reply.

Let me first say that the new application is more focused on the AHM560 documents than it is on the actual weight and balance.

I understand the change in CG as fuel is burned and how the CG point moves during the flight and its relation to envelopes.

It might not have been clear: the C5 sheet is filled in such a way that instead of having one big table with all values, there is a set of tables (forward & aft values) for each envelope type due to each having many cornerpoints. So there's C5a for just ZFW, C5d for just LAW, and there there's the confusing bit.

My confusion comes from envelopes on both C5b and C5c having been filled with MTOW as the type, but then they are distinguished from one another by one being labeled Take Off, and the other Inflight.

http://img703.imageshack.us/img703/4771/48760147.png

http://img97.imageshack.us/img97/7615/48164184.png

I'm thinking, MTOW is for take off, so what is this Inflight label I'm seeing? Again, I'm more interested in the correct wording of it on the document than in the working of it in the W&B system.

[Ajay SAXENA]

Hi

I think you want to create digital response for generating trim sheet.

You perhaps need to know as to why there is variation in H-arm of AHM and WBM say for pilot position, row arms, understand from where AHM shows 500 kg multiple of fuel whereas WBM is in multiple of 400 ltrs.

If you know as to how the trim tab calculation is arrived at please share with me

All the best for your mission.

AB

[Retired Redcap]

The first set of tables are MTOW (max take off weight) and do specify for the trim condition at take off.
The inflight tables refer to the trim perameters for that condition. for various reasons they are "wider" than the MTOW limits.
Weight and balance calculations for normal operations consider the trim perameter for three conditions, take off, landing and zero fuel. All of these are more restrictive than the in flight condition.
I hope this helps you.