Cessna 172P - Page 14

WEIGHT
AND BALANCE
TERMINOLOGY
Reference Reference
Datum ls an
lmaglnary
vertloal
plane
from
Datum
which all horizontal
distances are mea,sured for
balance
purposes.
Station
Station is a location
along the airplane fuselage
given
in
terms of the distance
from the retorenoe
datum.
SECTION 1
GENERAL
Arm
Moment
Center of
Gravity
(c.G.)
c.G.
Arm
c.G.
Limits
Standard
Empty
Weight
Basic Empty
Weight
Useful
Load
Maximum
Ramp
Weight
Maximum
Takeoff
Weight
CESSNA
MODEL 1?2P
Arm is the horizontal distance
from the
reference datum to
the center of
gravity
(C.G.)
of
an
ltem.
Moment
is the
product
of
the weight of an item multiplied
by
its arm.
(Moment divided by the sonstant 1000
is
used
i.n
this handbook
to simplify balance
calculations by
reduc-
ing the number
of
digits.)
Center of
Gravity is tho
point
at which an
airplane, or
equipment,
would balance
if
suspended. Its
distance from
the refergnce datum is found by dividing
the total moment
by
the
total weight of
the
airplane.
Center of Gravlty A¡rn is the arm obtained
by adding
the
airplane's individual moments
and dividing the sum by
the total weight.
Center of
Gravlty
Limits
are
the extreme conter
of
gravity
losations within which the airplane must be operated at a
given
weight.
Standa¡d Empty
llleight is
the
weight of a stanclard air-
plane,
including unusable fuel,
full
operating fluids
and
full engine
oil.
Basic Empty llfeight is the standard empty
weight
plus
tlre
weight of
optional
equipment.
Useful
Load is
the
difference between
ra,mp
weight and
the
basic
empty weight.
Maximum
Romp
Weight
is the maximum
weight
approved
for
ground
maneuver.
(It
includes
the weight
of start,
taxi,
and
runup
fuel.)
Maximum Tal¡eoff Weight is the maximum
weight ap-
proved
for
the start of
the takeoff run.
1-8
30 May
1980