Embraer EMB145 Operation Manual page 937

WEIGHT AND
AIRPLANE
BALANCE
OPERATIONS
MANUAL
MEAN AERODYNAMIC CHORD (MAC)
This is the chord of an imaginary rectangular airfoil with the same area
of the actual wing and which produces the same resulting force vectors
of the actual wing. The aircraft forward and aft CG limits are referred to
in terms of %MAC.
INDEX SYSTEM
This is a convention for presenting aircraft or body moments. It is the
moment of the body converted to a different measuring system.
Page Code
3 01
1-06-10
SEPTEMBER 20, 1999