Cirrus SR22 Pilot's Operating Handbook And Flight Manual page 178

Section 6
Weight and Balance Data
main wheel centers to a plumb bob dropped from the forward
side of the firewall (FS 100). Add 100 to this measurement to
obtain left and right weighing point arm (dimension 'A').
Typically, dimension 'A' will be in the neighborhood of 157.5.
b. Obtain measurement 'y' by measuring horizontally and
parallel to the airplane centerline (BL 0), from center of
nosewheel axle, left side, to a plumb bob dropped from the
line stretched between the main wheel centers. Repeat on
right side and average the measurements. Subtract this
measurement from dimension 'A' to obtain the nosewheel
weighing point arm (dimension 'B').
5. Determine and record the moment for each of the main and nose
gear weighing points using the following formula:
6. Calculate and record the as-weighed weight and moment by
totaling the appropriate columns.
7. Determine and record the as-weighed CG in inches aft of datum
using the following formula:
8. Add or subtract any items not included in the as-weighed condition
to determine the empty condition. Application of the above CG
formula will determine the C.G for this condition.
9. Add the correction for engine oil (15 lb at FS 78.4), if the airplane
was weighed with oil drained. Add the correction for unusable fuel
(15.0 lb at FS 154.9) to determine the Basic Empty Weight and
Moment. Calculate and record the Basic Empty Weight CG by
applying the above CG formula.
10. Record the new weight and CG values on the Weight and Balance
Record.
The above procedure determines the airplane Basic Empty Weight,
moment, and center of gravity in inches aft of datum. CG can also be
expressed in terms of its location as a percentage of the airplane
Mean Aerodynamic Cord (MAC) using the following formula:
CG% MAC = 100 x (CG Inches – LEMAC) / MAC
Where:
6-6
Moment = Net Weight x Arm
CG = Total Moment / Total Weight
LEMAC = 133.1
MAC = 47.7
Cirrus Design
SR22
P/N 13772-004
Original Issue