The simulation does this sum every time you move a slider. It uses an example aircraft with made-up figures, the same one as the flight computer's loading tool. It is not a real type.
TRY IT
Load it and watch the balance point move
The aircraft balances on its CG, and every arm is drawn to scale. The chart plots total weight against CG. Each load sits at one arm, as in a loading table.
Example aircraft with made-up figures, not a real type: empty weight 705 kg with its CG at 1.00 m, maximum take-off weight 1,100 kg, CG limits 0.92 to 1.20 m, fuel at 0.72 kg per litre.
Take-off weight
1,036 kg
CG at take-off
1.087 m
CG at zero fuel
1.075 m
Inside the envelope at take-off and with the fuel gone.
Try a loading
Weight limits and CG limits
An aircraft has a maximum weight, and it has forward and aft limits for its CG. The envelope puts both on one chart.
The CG limits envelope is the enclosed area on a graph of the airplane loaded weight and the CG location. If lines drawn from the weight and CG cross within this envelope, the airplane is properly loaded.
An aircraft is loaded to its maximum take-off weight with the CG in the middle of its limits. You add one more bag, placed exactly at the CG. Is it within limits?
This example aircraft keeps the same CG limits at every weight, so its envelope is a rectangle. Some aircraft have limits that change with weight, which gives their envelope sloping sides.
For some aircraft, both fore and aft CG limits may be specified to vary as gross weight changes.
If the CG is too far aft, the aircraft may rotate prematurely on take-off or tend to pitch up during climb. If it's too far forward, it may be difficult to rotate for take-off or landing.
In this example aircraft every load and the empty aircraft sit aft of the forward limit, so no loading can reach it, and no loading that passes at take-off fails with the fuel gone.
The rule applies during the flight, as well as when it begins.
At all times you must ensure that the aircraft is loaded and operated within its weight and balance limits.
The pilot in command of an aircraft for a flight contravenes this subregulation if, during the flight, the aircraft ceases to be operated in accordance with the aircraft’s weight and balance limits.
The probability of overloading in small aircraft by assuming a passenger’s weight is considerable. Therefore, it is recommended you use actual known passenger weight.