Jabiru Aircraft
Pilot Operating Handbook
Model J170-D
JP-FM-13
Revision:
0
1
2
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4
28 Feb 2020
Page 6-60
6.5 TRIM SHEETS
The trim sheets included below, when used correctly, provide a means of calculating the aircraft
weight and CG position without manual calculations. An example of using the sheet is included
for reference.
6.5.1
Index Units
The chart is based on an aircraft “EMPTY WEIGHT TRIM INDEX” which is calculated using the
following formula:
Empty Weight Trim Index
=
{(Aircraft Empty Weight) * (Empty Weight Arm)}
1000
For reference, the example below shows two 85kg people, 5kg in Baggage Zone and 60L of fuel.
The
aircraft’s starting Index Unit is 54.4 at 320kg.
Example Trim Index Calculation:
Aircraft Empty Weight
=
320-kg
Aircraft Empty Weight Arm
=
170-mm aft of datum
Empty Weight Trim Index
=
(320 x 170) / 1000
=
54.4
6.5.2
Calculate Aircraft Weights
1-1
Use the Aircraft Empty Weight obtained from the latest aircraft weighing records to
enter the vertical “Aircraft Empty Weight Scale” on right hand side of the chart.
1-2
Move horizontally to the left into the next scale which is the “Crew Weight” Scale.
1-3
Move vertically downward one line on this scale for each 10-kg of weight that is placed
on the front seats, and mark a point.
1-4
Move horizontally to the left from the point made in Step 1-3 to enter the next scale
which is the “Baggage Weight” Scale.
1-5
Move vertically downward one line on this scale for each 5-kg of weight that is placed
in Baggage Zone and mark a point.
1-6
Move horizontally to the left from the point made in Step 1-5 to enter the next scale
which is the “Fuel Quantity” Scale and mark a point, This point is the “Zero Fuel Weight
Reference Point”
1-7
Move Horizontally to the left of the “Zero Fuel Reference Point” and Mark a “Zero Fuel
Weight Line” across the “Aircraft Trim Condition” Graph.
1-8
From the “Zero Fuel Point” on the “Fuel Quantity Scale” (marked in Step 1-6), move
vertically downward one line for each 10-
litres
of fuel being carried at the take-off
condition. Mark this “Take-Off Fuel Point” on the scale.
1-9
Move horizontally to the left, and
mark a “Take-Off Fuel Weight Line” across the
“Aircraft Trim Condition” graph.
