Introduction
Weight and balance data allows the pilot to determine the
loaded weight of the aircraft and determine whether or not
the loaded center of gravity (CG) is within the allowable
range for the weight. See Figure 5-1 for an example of the
data necessary for these calculations.
Single-Engine Aircraft Weight
and Balance Computations
Chapter 5
3,200
3,000
2,800
2,600
2,400
2,200
2,000
1,800 32 34 36 38 40 42 44 46 48
Fuselage station (in)
Loaded aircraft weight (lb)
Airplane basic empty weight 1,874.0 lb, EWCG +36.1
CG range (+40.9) to (+46.0) at 3,100 lb
(+33.0) to (+46.0) at 2,250 lb or less
Straight line variation between points
given
Empty weight CG range None
Maximum weight 3,100 lb takeoff/flight
2,950 lb landing
No. of seats 4 (2 front at +37.0)
(2 rear at +74.0)
Maximum baggage 160 lb
Area A (100 lb at +97.0)
Area B (60 lb at +116.0)
Fuel capacity 92 gal (88 gal usable); two 46 gal
integral tanks in wings at +46.6
Oil capacity 12 qt (−15)
Figure 5-1. Weight and balance data needed to determine proper
loading of a small airplane.
100 lb
max
60 lb
max
Datum Front seats +37 Rear seats +74 Baggage B +116
Fuel +46.6 Baggage A +97
88 gal usable
EWCG 36.1
Figure 5-2. Airplane loading diagram.
Determining the Loaded Weight and CG
An important part of preflight planning is determining that
the aircraft is loaded so its weight and CG location are within
the allowable limits. The methods of accomplishing this are
the manual computational method using weights, arms, and
moments; the chart method using weight and moment indexes
[Figure 5-2]; and the loading graph method, which eliminates
the need for some mathematical calculations.
Manual Computational Method
The manual computational method uses weights, arms, and
moments. It relates the total weight and CG location to a CG
limits chart similar to those included in the Type Certificate
Data Sheet (TCDS) and the Pilot’s Operating Handbook/
Aircraft Flight Manual (POH/AFM).
A worksheet, such as the one shown in Figure 5-3, provides
a means to record and compute pertinent weights, arms, and
moments for all onboard fuel, personnel, equipment, cargo,
and baggage that is not included in the aircraft’s basic empty
weight (BEW). Figure 5-4 is a sample of a typical equipment
list where many of the pertinent weights and moment values
can be found.
As part of preflight planning, fill in the blanks in the
worksheet with the specific data for the flight. The following
weights were used to complete the sample weight and balance
worksheet in Figure 5-3.
Pilot ................................................................120 lb
Front seat passenger .......................................180 lb
Rear seat passenger ........................................175 lb
Fuel (88 gal) ...................................................528 lb
Baggage A ......................................................100 lb
Baggage B ........................................................50 lb
Multiply each item’s weight by its arm to determine the
moment. Then, determine the total weight and the sum of
the moments. Divide the total moment by the total weight to
determine the CG in inches from the datum. For this example,
the total weight is 3,027 pounds and the CG is 43.54 inches
aft of the datum (a negative result would have indicated a
CG forward of the datum).
To determine whether or not the airplane is properly loaded
for this flight, use the CG limits chart. [Figure 5-5] Draw a
line vertically upward from the CG of 43.54 inches and one
horizontally to the right from the loaded weight of 3,027
pounds. These lines cross inside the envelope, which shows
the airplane is properly loaded for takeoff, but 77 pounds
overweight for landing. Note that for this sample chart, the
envelope is defined by the solid black line that indicates
CG limits at or below the maximum weight for takeoff
and landing. There is an additional region identified by a
segmented black line that includes weights suitable only for
takeoff. It is important to note these subtle differences as they
may or may not be found in every POH/AFM.
Item Weight (3,100 lb max.) Arm (in) Moment (lb-in) CG (inches from datum)
67,651.4
+43.54
Airplane
Front seats
Rear seats
Fuel (88 gal usable)
Baggage A (100 max.)
Baggage B (60 max.)
1,874 36.1
37.0
74.0
46.6
97.0
116.0
300
175
528
100
50
3,027
11,100.0
12,950.0
24,604.8
9,700.0
5,800.0
131,806.2
x =
Figure 5-3. Loading schedule chart derived from loading problem.
* Indicates total weight/arm for all subcomponents
Figure 5-4. Typical equipment list.