TOMARK, s.r.o.
Airplane Maintenance Manual
Chapter 08 Leveling & Weighing
Page 78
Issue: 11.AUG 2016
The position of the centre of gravity expressed in % of the mean
aerodynamic chord bMAC is then calculated on the basis of the
formula:
x
T
[% MAC] = x
T
/ MAC · 100 %
Calculation Formulae
The procedure below is aimed to calculate the position of the max
fwd and max rear CG for this individual airplane. Once it is verified
that they fall between the design limits CG range of table below, then
this means that the CG will always be between the design CG limit
during any phase of the flight. It is nevertheless responsibility of the
pilot to make sure that the MTOM is not exceeded (See section 2). In
case a modification is performed on the airplane the procedure
should be repeated and the values recorded.
For the calculation of the CG position it is necessary to know the
length of the mean aerodynamic chord (MAC). The calculated CG
position must be within the range specified by the manufacturer.
MAC
1.29 m
Design limit of operational CG range
24 - 32% MAC
Weighing Procedure
When establishing the CG position and the subsequent calculation of
the CG position as % MAC proceed as follows:
NOTE
Weigh the aircraft only on even floor and in closed shops (wind
protected). Use identical scales.
▶
Put the airplane on three scales as per Chapter
▶
Level the aircraft as per Chapter
Weighing of the airplane for the establishment of the allowed front-
most CG position:
▶
Completely fill fuel tanks.
▶
Ensure aircraft’s luggage compartment is empty.
▶
Occupy the pilot’s seat with the minimum allowed weight (55 kg).
▶
Read the weight readings of the scales under the wheels of the main
landing gear (m
R
and m
L
respectively).
▶
Read the weight reading of the scale under the wheel of the front
landing gear.