WEIGHT AND
BALANCE
Building this type of table consists of determining the .index(XXX kg) and rounding it to the closest unit or closest tenth, depending on the airline procedure.
WEIGHT AND
BALANCE
C. BALANCE CHART DESIGN
4.2. Operational limits diagram
The operational limits are represented on a diagram . on X-axis the aircraft index values . on Y-axis the aircraft weight values
Then iso-CG lines are represented to enable the user to determine finally the aircraft CG position value in %RC.
It is based on the index formula expressed in %RC. Weight ×
(%RC -Ref%)
Index =×
MAC +
K
C
With: C and K constants depending on the aircraft type MAC = Mean Aerodynamic Chord of the aircraft.
. For CG = Ref% then Weight ×
(Ref% -Ref%)
Index =×
MAC +
K
C Index = K, whatever the weight value.
Index
Index = K
C. BALANCE CHART DESIGN
. For other CG values then:
The index values corresponding to two weights W1 and W2 are linked by the iso-CG line. W (CG -Ref%) W (CG -Ref%)
1a 2a
Index1 =×
MAC +
K and Index 2 =×
MAC +
K
CC
Ref-3 Ref-1 Ref+1 Ref+3
Index
Index = K
When the diagram is prepared the operational limits can be drawn on it : . —takeoff“ operational limit (the limit resulting from the operational margins computation and the selection of the more limiting part between takeoff, landing and in flight operational limits) . zero fuel operational limit.
WEIGHT AND
BALANCE
WEIGHT AND
BALANCE
C. BALANCE CHART DESIGN
5. THE AHM560
The AHM560 is a standardized IATA document containing weight and trimming data necessary for both the aircraft CG position and the operational limits calculations. The computerized balance chart systems (EDP systems) are based on the data provided in the AHM560. Part of this document contains the results from the balance chart design process, other information is linked to operators‘ needs in term of EDP system computation and EDP system output. A specific AHM560 should be used by airlines for each type of aircraft they have, information given in the AHM560 can be applied to several aircraft registrations, provided those aircraft have the same Weight & Balance characteristics (same weight variants, same certified limits, same cabin layout, etc.).
5.1. Generalities
The AHM560 is divided into four main parts:
. PART A: COMMUNICATION ADDRESSES
. PART B: GENERAL INFORMATION
. PART C: AIRCRAFT DATA
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