C. BALANCE CHART DESIGN
3.4.1. Inaccuracy on cargo loading on board the aircraft
a) Inaccuracy on the cargo location
For cargo loading, two sources of inaccuracies have to be considered.
. On the one hand, on the balance chart the cargo influence is taken into account as a delta index per cargo compartment (CARGO 1, CARGO2…), this delta index is based on an average H-arm for the corresponding compartment. Now the real loading may have an average H-arm different from the average one. This difference will generate an inaccuracy on the aircraft CG determination. This inaccuracy is named cargo distribution inaccuracy.
. On the other hand, when determining the average cargo compartment H-arm, each cargo position CG is known with a certain inaccuracy, this inaccuracy will generate an inaccuracy on the aircraft CG determination. This inaccuracy is named cargo CG tolerance inaccuracy.
. Cargo distribution inaccuracy:
Eitem location = Witem x (H-armitem real . H-armitem assumed)
For this inaccuracy determination the different loading scenarios have to be studied. For each of them, Eitem location is determined with H-armitem assumed being H-armCargoX and H-armitem real being the H-arm of the studied configuration.
The process for checking the different configuration is the following : . Determine the cargo compartment average H-arm : refer to paragraph 2.5 .Index for cargo loading.
. Study each configuration separately (containers, pallets 88“, pallets96“ and/or Bulk)
. For each configuration the forward inaccuracy is determined when all the positions in front of the average H-arm are full and all the positions aft of the average H-arm are empty.
. For each configuration the aft inaccuracy is determined when all the positions aft of the average H-arm are full and all the positions in front of the average H-arm are empty.
. Determine the configuration generating the highest inaccuracy.
This inaccuracy needs to be determined for each cargo compartment that is represented on the balance chart. Then the total inaccuracy is determined considering each cargo compartment inaccuracy independent from the other ones.
22 2 2 2
Ecargo distibution fwd =.
E cargo1fwd+E cargo2fwd+E cargo3fwd+E cargo4fwd+E cargo5fwd
222 22
Ecargo distibution aft =+
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