9-1

Introduction

Compliance with the weight and balance limits of any aircraft 

is critical to flight safety. Operating above the maximum 

weight limitation compromises the structural integrity of 

an aircraft and adversely affects its performance. Operation 

with the center of gravity (CG) outside the approved limits 

results in control difficulty.

Weight Control

As discussed in Chapter 4, Aerodynamics of Flight, weight 

is the force with which gravity attracts a body toward the 

center of the Earth. It is a product of the mass of a body and 

the acceleration acting on the body. Weight is a major factor 

in aircraft construction and operation, and demands respect 

from all pilots. 

The force of gravity continuously attempts to pull an aircraft 

down toward Earth. The force of lift is the only force that 

counteracts weight and sustains an aircraft in flight. The 

amount of lift produced by an airfoil is limited by the airfoil 

design, angle of attack (AOA), airspeed, and air density. To 

assure that the lift generated is sufficient to counteract weight, 

loading an aircraft beyond the manufacturer’s recommended 

weight must be avoided. If the weight is greater than the lift 

generated, the aircraft may be incapable of flight.

Effects of Weight

Any item aboard the aircraft that increases the total weight 

is undesirable for performance. Manufacturers attempt to 

make an aircraft as light as possible without sacrificing 

strength or safety.

Weight and 

Balance

Chapter 9
9-2

Lateral or longitudinal unbalance

Lateral unbalance will cause wing heaviness.

Empty Full

Excess baggage

Longitudinal unbalance will cause 

either nose or tail heaviness.

Figure 9-1. Lateral and longitudinal unbalance.

The pilot should always be aware of the consequences of 

overloading. An overloaded aircraft may not be able to leave 

the ground, or if it does become airborne, it may exhibit 

unexpected and unusually poor flight characteristics. If not 

properly loaded, the initial indication of poor performance 

usually takes place during takeoff. 

Excessive weight reduces the flight performance in almost 

every respect. For example, the most important performance 

deficiencies of an overloaded aircraft are:

• Higher takeoff speed

• Longer takeoff run

• Reduced rate and angle of climb

• Lower maximum altitude

• Shorter range

• Reduced cruising speed

• Reduced maneuverability

• Higher stalling speed

• Higher approach and landing speed

• Longer landing roll

• Excessive weight on the nose wheel or tail wheel

The pilot must be knowledgeable about the effect of weight 

on the performance of the particular aircraft being flown. 

Preflight planning should include a check of performance 

charts to determine if the aircraft’s weight may contribute 

to hazardous flight operations. Excessive weight in itself 

reduces the safety margins available to the pilot, and becomes 

even more hazardous when other performance-reducing 

factors are combined with excess weight. The pilot must 

also consider the consequences of an overweight aircraft if 

an emergency condition arises. If an engine fails on takeoff 

or airframe ice forms at low altitude, it is usually too late to 

reduce an aircraft’s weight to keep it in the air.

Weight Changes

The operating weight of an aircraft can be changed by 

simply altering the fuel load. Gasoline has considerable 

weight—6 pounds per gallon. Thirty gallons of fuel may 

weigh more than one passenger. If a pilot lowers airplane 

weight by reducing fuel, the resulting decrease in the range 

of the airplane must be taken into consideration during flight 

planning. During flight, fuel burn is normally the only weight 

change that takes place. As fuel is used, an aircraft becomes 

lighter and performance is improved.

Changes of fixed equipment have a major effect upon the 

weight of an aircraft. The installation of extra radios or 

instruments, as well as repairs or modifications may also 

affect the weight of an aircraft.

Balance, Stability, and Center of Gravity

Balance refers to the location of the CG of an aircraft, and is 

important to stability and safety in flight. The CG is a point 

at which the aircraft would balance if it were suspended at 

that point.

The primary concern in balancing an aircraft is the fore and 

aft location of the CG along the longitudinal axis. The CG 

is not necessarily a fixed point; its location depends on the 

distribution of weight in the aircraft. As variable load items are 

shifted or expended, there is a resultant shift in CG location. 

The distance between the forward and back limits for the 

position of the center for gravity or CG range is certified for 

an aircraft by the manufacturer. The pilot should realize that 

if the CG is displaced too far forward on the longitudinal 

axis, a nose-heavy condition will result. Conversely, if the 

CG is displaced too far aft on the longitudinal axis, a tail 

heavy condition results. It is possible that the pilot could not 

control the aircraft if the CG location produced an unstable 

condition. [Figure 9-1]

Location of the CG with reference to the lateral axis is also 

important. For each item of weight existing to the left of the 

fuselage centerline, there is an equal weight existing at a 

corresponding location on the right. This may be upset by 

unbalanced lateral loading. The position of the lateral CG 

is not computed in all aircraft, but the pilot must be aware 

that adverse effects arise as a result of a laterally unbalanced 

condition. In an airplane, lateral unbalance occurs if the fuel 

load is mismanaged by supplying the engine(s) unevenly from 

tanks on one side of the airplane. The pilot can compensate 

for the resulting wing-heavy condition by adjusting the 
9-3

trim or by holding a constant control pressure. This action 

places the aircraft controls in an out-of-streamline condition, 

increases drag, and results in decreased operating efficiency. 

Since lateral balance is addressed when needed in the aircraft 

flight manual (AFM) and longitudinal balance is more 

critical, further reference to balance in this handbook means 

longitudinal location of the CG. A single pilot operating a 

small rotorcraft, may require additional weight to keep the 

aircraft laterally balanced.

Flying an aircraft that is out of balance can produce increased 

pilot fatigue with obvious effects on the safety and efficiency 

of flight. The pilot’s natural correction for longitudinal 

unbalance is a change of trim to remove the excessive control 

pressure. Excessive trim, however, has the effect of reducing 

not only aerodynamic efficiency but also primary control 

travel distance in the direction the trim is applied.

Effects of Adverse Balance

Adverse balance conditions affect flight characteristics in 

much the same manner as those mentioned for an excess 

weight condition. It is vital to comply with weight and 

balance limits established for all aircraft, especially rotorcraft. 

Operating above the maximum weight limitation compromises 

the structural integrity of the rotorcraft and adversely affects 

performance. Balance is also critical because on some fully 

loaded rotorcraft, CG deviations as small as three inches can 

dramatically change handling characteristics. Stability and 

control are also affected by improper balance.

Stability

Loading in a nose-heavy condition causes problems in 

controlling and raising the nose, especially during takeoff 

and landing. Loading in a tail heavy condition has a serious 

effect upon longitudinal stability, and reduces the capability 

to recover from stalls and spins. Tail heavy loading also 

produces very light control forces, another undesirable 

characteristic. This makes it easy for the pilot to inadvertently 

overstress an aircraft.

It is important to reevaluate the balance in a rotorcraft 

whenever loading changes. In most aircraft, off-loading a 

passenger is unlikely to adversely affect the CG, but offloading a passenger from a rotorcraft can create an unsafe 

flight condition. An out-of-balance loading condition also 

decreases maneuverability since cyclic control is less 

effective in the direction opposite to the CG location. 

Limits for the location of the CG are established by the 

manufacturer. These are the fore and aft limits beyond 

which the CG should not be located for flight. These limits 

are published for each aircraft in the Type Certificate Data 

Sheet (TCDS), or aircraft specification and the AFM or 

pilot’s operating handbook (POH). If the CG is not within the 

allowable limits after loading, it will be necessary to relocate 

some items before flight is attempted.

The forward CG limit is often established at a location that 

is determined by the landing characteristics of an aircraft. 

During landing, one of the most critical phases of flight, 

exceeding the forward CG limit may result in excessive loads 

on the nosewheel, a tendency to nose over on tailwheel type 

airplanes, decreased performance, higher stalling speeds, and 

higher control forces. 

Control

In extreme cases, a CG location that is beyond the forward 

limit may result in nose heaviness, making it difficult or 

impossible to flare for landing. Manufacturers purposely 

place the forward CG limit as far rearward as possible to 

aid pilots in avoiding damage when landing. In addition to 

decreased static and dynamic longitudinal stability, other 

undesirable effects caused by a CG location aft of the 

allowable range may include extreme control difficulty, 

violent stall characteristics, and very light control forces 

which make it easy to overstress an aircraft inadvertently.

A restricted forward CG limit is also specified to assure 

that sufficient elevator/control deflection is available at 

minimum airspeed. When structural limitations do not limit 

the forward CG position, it is located at the position where 

full-up elevator/control deflection is required to obtain a high 

AOA for landing.

The aft CG limit is the most rearward position at which the 

CG can be located for the most critical maneuver or operation. 

As the CG moves aft, a less stable condition occurs, which 

decreases the ability of the aircraft to right itself after 

maneuvering or turbulence.

For some aircraft, both fore and aft CG limits may be 

specified to vary as gross weight changes. They may also 

be changed for certain operations, such as acrobatic flight, 

retraction of the landing gear, or the installation of special 

loads and devices that change the flight characteristics.

The actual location of the CG can be altered by many variable 

factors and is usually controlled by the pilot. Placement of 

baggage and cargo items determines the CG location. The 

assignment of seats to passengers can also be used as a means 

of obtaining a favorable balance. If an aircraft is tail heavy, it 

is only logical to place heavy passengers in forward seats.

Fuel burn can also affect the CG based on the location of the 

fuel tanks. For example, most small aircraft carry fuel in the 
9-4

wings very near the CG and burning off fuel has little effect 

on the loaded CG. On rotorcraft, the fuel tanks are often 

located behind the CG and fuel consumption from a tank 

aft of the rotor mast causes the loaded CG to move forward. 

A rotorcraft in this condition has a nose-low attitude when 

coming to a hover following a vertical takeoff. Excessive 

rearward displacement of the cyclic control is needed to 

maintain a hover in a no-wind condition. Flight should not 

be continued since rearward cyclic control fades as fuel is 

consumed. Deceleration to a stop may also be impossible. In 

the event of engine failure and autorotation, there may not be 

enough cyclic control to flare properly for a landing. 

Management of Weight and Balance Control

Title 14 of the Code of Federal Regulations (14 CFR) section 

23.23 requires establishment of the ranges of weights and 

CGs within which an aircraft may be operated safely. The 

manufacturer provides this information, which is included in 

the approved AFM, TCDS, or aircraft specifications.

While there are no specified requirements for a pilot operating 

under 14 CFR part 91 to conduct weight and balance 

calculations prior to each flight, 14 CFR section 91.9 requires 

the pilot in command (PIC) to comply with the operating 

limits in the approved AFM. These limits include the weight 

and balance of the aircraft. To enable pilots to make weight 

and balance computations, charts and graphs are provided 

in the approved AFM.

Weight and balance control should be a matter of concern to 

all pilots. The pilot controls loading and fuel management 

(the two variable factors that can change both total weight 

and CG location) of a particular aircraft. The aircraft owner 

or operator should make certain that up-to-date information 

is available for pilot use, and should ensure that appropriate 

entries are made in the records when repairs or modifications 

have been accomplished. The removal or addition of 

equipment results in changes to the CG.

Weight changes must be accounted for and the proper 

notations made in weight and balance records. The equipment 

list must be updated, if appropriate. Without such information, 

the pilot has no foundation upon which to base the necessary 

calculations and decisions.

Standard parts with negligible weight or the addition of 

minor items of equipment such as nuts, bolts, washers, 

rivets, and similar standard parts of negligible weight on 

fixed-wing aircraft do not require a weight and balance 

check. Rotorcraft are, in general, more critical with respect 

to control with changes in the CG position. The following 

criteria for negligible weight change is outlined in Advisory 

Circular (AC) 43.13-1 (as revised), Methods Techniques and 

Practices—Aircraft Inspection and Repair: 

• One pound or less for an aircraft whose weight empty 

is less than 5,000 pounds; 

• Two pounds or less for aircraft with an empty weight 

of more than 5,000 pounds to 50,000 pounds; 

• Five pounds or less for aircraft with an empty weight 

of more than 50,000 pounds. 

Negligible CG change is any change of less than 0.05 percent 

Mean Aerodynamic Chord (MAC) for fixed-wing aircraft, 0.2 

percent of the maximum allowable CG range for rotorcraft. 

Exceeding these limits would require a weight and balance 

check. 

Before any flight, the pilot should determine the weight 

and balance condition of the aircraft. Simple and orderly 

procedures based on sound principles have been devised 

by the manufacturer for the determination of loading 

conditions. The pilot uses these procedures and exercises 

good judgment when determining weight and balance. In 

many modern aircraft, it is not possible to fill all seats, 

baggage compartments, and fuel tanks, and still remain within 

the approved weight and balance limits. If the maximum 

passenger load is carried, the pilot must often reduce the fuel 

load or reduce the amount of baggage.

14 CFR part 125 requires aircraft with 20 or more seats or 

weighing 6,000 pounds or more to be weighed every 36 

calendar months. Multi-engine aircraft operated under a 

14 CFR part 135 are also required to be weighed every 36 

months. Aircraft operated under 14 CFR part 135 are exempt 

from the 36 month requirement if operated under a weight 

and balance system approved in the operations specifications 

of the certificate holder. AC 43.13-1, Acceptable Methods, 

Techniques and Practices—Aircraft Inspection and Repair 

also requires that the aircraft mechanic must ensure the 

weight and balance data in the aircraft records is current and 

accurate after a 100-hour or annual inspection.

Terms and Definitions

The pilot should be familiar with terms used in working 

problems related to weight and balance. The following list 

of terms and their definitions is standardized, and knowledge 

of these terms aids the pilot to better understand weight and 

balance calculations of any aircraft. Terms defined by the 

General Aviation Manufacturers Association (GAMA) as 

industry standard are marked in the titles with GAMA.
9-5

• Arm (moment arm)—the horizontal distance in inches 

from the reference datum line to the CG of an item. The 

algebraic sign is plus (+) if measured aft of the datum, 

and minus (–) if measured forward of the datum.

• Basic empty weight (GAMA)—the standard empty 

weight plus the weight of optional and special 

equipment that have been installed.

• Center of gravity (CG)—the point about which an 

aircraft would balance if it were possible to suspend 

it at that point. It is the mass center of the aircraft, 

or the theoretical point at which the entire weight of 

the aircraft is assumed to be concentrated. It may be 

expressed in inches from the reference datum, or in 

percent of MAC. The CG is a three-dimensional point 

with longitudinal, lateral, and vertical positioning in 

the aircraft.

• CG limits—the specified forward and aft points 

within which the CG must be located during flight. 

These limits are indicated on pertinent aircraft 

specifications.

• CG range—the distance between the forward and aft CG 

limits indicated on pertinent aircraft specifications.

• Datum (reference datum)—an imaginary vertical plane 

or line from which all measurements of arm are taken. 

The datum is established by the manufacturer. Once 

the datum has been selected, all moment arms and the 

location of CG range are measured from this point.

• Delta—a Greek letter expressed by the symbol  to 

indicate a change of values. As an example, CG 

indicates a change (or movement) of the CG.

• Floor load limit—the maximum weight the floor 

can sustain per square inch/foot as provided by the 

manufacturer.

• Fuel load—the expendable part of the load of the 

aircraft. It includes only usable fuel, not fuel required 

to fill the lines or that which remains trapped in the 

tank sumps.

• Licensed empty weight—the empty weight that 

consists of the airframe, engine(s), unusable fuel, and 

undrainable oil plus standard and optional equipment 

as specified in the equipment list. Some manufacturers 

used this term prior to GAMA standardization.

• Maximum landing weight—the greatest weight that 

an aircraft normally is allowed to have at landing.

• Maximum ramp weight—the total weight of a loaded 

aircraft, and includes all fuel. It is greater than the 

takeoff weight due to the fuel that will be burned during 

the taxi and runup operations. Ramp weight may also 

be referred to as taxi weight.

• Maximum takeoff weight—the maximum allowable 

weight for takeoff.

• Maximum weight—the maximum authorized weight 

of the aircraft and all of its equipment as specified in 

the TCDS for the aircraft.

• Maximum zero fuel weight (GAMA)—the maximum 

weight, exclusive of usable fuel.

• Mean aerodynamic chord (MAC)—the average 

distance from the leading edge to the trailing edge of 

the wing.

• Moment—the product of the weight of an item 

multiplied by its arm. Moments are expressed in 

pound-inches (in-lb). Total moment is the weight of 

the airplane multiplied by the distance between the 

datum and the CG.

• Moment index (or index)—a moment divided by a 

constant such as 100, 1,000, or 10,000. The purpose of 

using a moment index is to simplify weight and balance 

computations of aircraft where heavy items and long 

arms result in large, unmanageable numbers.

• Payload (GAMA)—the weight of occupants, cargo, 

and baggage.

• Standard empty weight (GAMA)—aircraft weight 

that consists of the airframe, engines, and all items of 

operating equipment that have fixed locations and are 

permanently installed in the aircraft, including fixed 

ballast, hydraulic fluid, unusable fuel, and full engine 

oil.

• Standard weights—established weights for numerous 

items involved in weight and balance computations. 

These weights should not be used if actual weights are 

available. Some of the standard weights are:

 Gasoline ............................................... 6 lb/US gal

 Jet A, Jet A-1 .................................... 6.8 lb/US gal

 Jet B ...................................................6.5 lb/US gal

 Oil ......................................................7.5 lb/US gal

 Water .....................................................8.35 lb/US gal

• Station—a location in the aircraft that is identified by 

a number designating its distance in inches from the 

datum. The datum is, therefore, identified as station 

zero. An item located at station +50 would have an 

arm of 50 inches.

• Useful load—the weight of the pilot, copilot, 

passengers, baggage, usable fuel, and drainable oil. It is 

the basic empty weight subtracted from the maximum 

allowable gross weight. This term applies to general 

aviation (GA) aircraft only.
9-6

100 50 lb lb

50

lb

25"

50" 100"

2,500

in-lb

2,500

in-lb

5,000

in-lb

Fulcrum

Datum

100 x 25 = 2,500

50 x 50 = 2,500

 Total = 5,000

Wt x Arm = Moment

(lb) x (in) = (in-lb)

Figure 9-4. Establishing a balance.

50

lb

100"

Moment = 5,000 in-lb

Fulcrum

Datum

Wt x Arm = Moment

(lb) x (in) = (in-lb)

50 x 100 = 5,000 Note: The datum is assumed to be

located at the fulcrum.

Figure 9-3. Determining moment.

Fwd limit Aft limit

Datum

CG

range

( + )

Arm

( – )

Arm

( + ) Arm 70"

Moment = 700 in-lb

Sta 0 Sta 70

10 lb

Figure 9-2. Weight and balance.

Principles of Weight and Balance Computations

It might be advantageous at this point to review and 

discuss some of the basic principles of weight and balance 

determination. The following method of computation can be 

applied to any object or vehicle for which weight and balance 

information is essential.

By determining the weight of the empty aircraft and adding 

the weight of everything loaded on the aircraft, a total weight 

can be determined—a simple concept. A greater problem, 

particularly if the basic principles of weight and balance are 

not understood, is distributing this weight in such a manner 

that the entire mass of the loaded aircraft is balanced around a 

point (CG) that must be located within specified limits.

The point at which an aircraft balances can be determined by 

locating the CG, which is, as stated in the definitions of terms, 

the imaginary point at which all the weight is concentrated. To 

provide the necessary balance between longitudinal stability 

and elevator control, the CG is usually located slightly 

forward of the center of lift. This loading condition causes 

a nose-down tendency in flight, which is desirable during 

flight at a high AOA and slow speeds.

As mentioned earlier, a safe zone within which the balance 

point (CG) must fall is called the CG range. The extremities 

of the range are called the forward CG limits and aft CG 

limits. These limits are usually specified in inches, along the 

longitudinal axis of the airplane, measured from a reference 

point called a datum reference. The datum is an arbitrary 

point, established by aircraft designers, which may vary in 

location between different aircraft. [Figure 9-2]

The distance from the datum to any component part or any 

object loaded on the aircraft, is called the arm. When the 

object or component is located aft of the datum, it is measured 

in positive inches; if located forward of the datum, it is 

measured as negative inches, or minus inches. The location 

of the object or part is often referred to as the station. If 

the weight of any object or component is multiplied by the 

distance from the datum (arm), the product is the moment. 

The moment is the measurement of the gravitational force 

that causes a tendency of the weight to rotate about a point 

or axis and is expressed in inch-pounds (in-lb).

To illustrate, assume a weight of 50 pounds is placed on 

the board at a station or point 100 inches from the datum. 

The downward force of the weight can be determined by 

multiplying 50 pounds by 100 inches, which produces a 

moment of 5,000 in-lb. [Figure 9-3]

To establish a balance, a total of 5,000 in-lb must be applied 

to the other end of the board. Any combination of weight 

and distance which, when multiplied, produces a 5,000 in-lb 

moment will balance the board. For example (illustrated in 

Figure 9-4), if a 100-pound weight is placed at a point (station) 

25 inches from the datum, and another 50-pound weight is 

placed at a point (station) 50 inches from the datum, the sum 

of the product of the two weights and their distances will total 

a moment of 5,000 in-lb, which will balance the board.
9-7

Item Weight Arm Moment

Aircraft Empty Weight 2,100 78.3 164,430

Front Seat Occupants 340 85.0 28,900

Rear Seat Occupants 350 121.0 42,350

Fuel 450 75.0 33,750

Baggage Area 1 80 150.0 12,000

Total 3,320 281,430

281,430 ÷ 3,320 = 84.8

Figure 9-5. Example of weight and balance computations.

Sample Loading Problem Weight (lb) Moment

(in-lb/1,000)

1. Basic Empty Weight (Use data pertaining 

 to aircraft as it is presently equipped.)

Includes unusable fuel and full oil

2. Usable Fuel (At 6 lb/gal)

 Standard Tanks (40 gal maximum) 

 Long Range Tanks (50 gal maximum) 

 Integral Tanks (62 gal maximum) 

 Integral Reduced Fuel (42 gal) 

3. Pilot and Front Passenger (Station 34 to 46) 

4. Rear Passengers 

5. Baggage Area 1 or Passenger on Child’s 

Seat (Station 82 to 108, 120 lb maximum)

6. Baggage Area 2

(Station 108 to 142, 50 lb maximum)

7. Weight and Moment

1,467 57.3

 240 11.5

 340 12.7

 300 21.8

 20 1.9

2,367 105.2

Figure 9-6. Weight and balance data.

Weight and Balance Restrictions

An aircraft’s weight and balance restrictions should be 

closely followed. The loading conditions and empty weight 

of a particular aircraft may differ from that found in the 

AFM/POH because modifications or equipment changes may 

have been made. Sample loading problems in the AFM/POH 

are intended for guidance only; therefore, each aircraft must 

be treated separately. Although an aircraft is certified for a 

specified maximum gross takeoff weight, it will not safely 

take off with this load under all conditions. Conditions that 

affect takeoff and climb performance, such as high elevations, 

high temperatures, and high humidity (high density altitudes) 

may require a reduction in weight before flight is attempted. 

Other factors to consider prior to takeoff are runway length, 

runway surface, runway slope, surface wind, and the presence 

of obstacles. These factors may require a reduction in weight 

prior to flight.

Some aircraft are designed so that it is difficult to load them 

in a manner that will place the CG out of limits. These are 

usually small aircraft with the seats, fuel, and baggage areas 

located near the CG limit. Pilots must be aware that while 

within CG limits these aircraft can be overloaded in weight.

Other aircraft can be loaded in such a manner that they will 

be out of CG limits even though the useful load has not been 

exceeded. Because of the effects of an out-of-balance or 

overweight condition, a pilot should always be sure that an 

aircraft is properly loaded.

Determining Loaded Weight and CG

There are various methods for determining the loaded weight 

and CG of an aircraft. There is the computational method, as 

well as methods that utilize graphs and tables provided by 

the aircraft manufacturer.

Computational Method

The following is an example of the computational method 

involving the application of basic math functions. 

Aircraft Allowances:

 Maximum gross weight...................... 3,400 pounds

 CG range............................................. 78–86 inches

Given:

 Weight of front seat occupants............. 340 pounds

 Weight of rear seat occupants.............. 350 pounds

 Fuel........................................................... 75 gallons

 Weight of baggage in area 1....................80 pounds

1. List the weight of the aircraft, occupants, fuel, and 

baggage. Remember that aviation gas (AVGAS) 

weighs 6 pounds per gallon and is used in this 

example.

2. Enter the moment for each item listed. Remember 

“weight x arm = moment.”

3. Find the total weight and total moment.

4. To determine the CG, divide the total moment by the 

total weight.

NOTE: The weight and balance records for a particular 

aircraft will provide the empty weight and moment, as well 

as the information on the arm distance. [Figure 9-5]

The total loaded weight of 3,320 pounds does not exceed 

the maximum gross weight of 3,400 pounds, and the CG of 

84.8 is within the 78–86 inch range; therefore, the aircraft is 

loaded within limits.

Graph Method

Another method for determining the loaded weight and CG is 

the use of graphs provided by the manufacturers. To simplify 

calculations, the moment may sometimes be divided by 100, 

1,000, or 10,000. [Figures 9-6, 9-7, and 9-8] 

Front seat occupants....................................340 pounds

Rear seat occupants ......................................300 pounds

Fuel.................................................................40 gallons

Baggage area 1 ...............................................20 pounds
9-8

Loading Graph

400

350

300

250

200

150

100

50

0 5 10 15 20 25 30

340

12.7

0 50 100 150 200 250 300 350 400

Load Moment/1,000 (Kilogram-Millimeters)

0

25

50

75

100

125

150

175

200

Load Weight (Kilograms)

Load Moment/1,000 (Inch-Pounds)

Load Weight (Pounds)

 Maximum Usable Fuel

 * Standard Tanks

 ** Long Range Tanks

 *** Internal Tanks

Pilot & Front Passenger

Rear Passengers

Baggage Area 1 or 

Passenger on Child’s Seat

Fuel (6 lb/gal; 0.72 kg/liter

62 gal***(234.7 liters)

Baggage Area 2

60 gal (227.1 liters)

50 gal**(189.3 liters)

42 gal reduced***(159 liters)

40 gal*(189.3 liters)

30 gal (113.6 liters)

20 gal (75.7 liters)

10 gal (37.9 liters)

Center of gravity moment envelope

2,400

2,300

2,200

2,100

2,000

1,900

1,800

1,700

1,600

1,50045 50 55 60 65 70 75 80 85 90 95 100 105 110

2,367

105.2

Loaded Airplane Moment/1,000 (Kilogram-Millimeters)

700

750

800

850

900

950

1,000

1,050

1,100

Loaded Airplane Weight (Kilograms)

Loaded Aircraft Moment/1,000 (Inch-Pounds)

Loaded Airplane Weight (Pounds)

600 700 800 900 1,000 1,100 1,200 1,300

Utility Category

Normal

Category

Figure 9-8. CG moment envelope.

Figure 9-7. Loading graph.
9-9

OIL

FUEL TANK

FUEL TANK

Occupants

Front Seat 

Arm 85

Rear Seats 

Arm 121

Moment

100 Weight Moment

100 Weight

120

130

140

150

160

170

180

190

200

120

130

140

150

160

170

180

190

200

102

110

119

128

136

144

153

162

170

145

157

169

182

194

206

218

230

242

Usable Fuel

Main Wing Tanks Arm 75

Gallons Weight Moment

100 

 5

10

15

20

25

30

35

40

44

30

 60

 90

120

150

180

210

240

264

22

45

68

90

112

135

158

180

198

Moment Limits vs Weight

Moment limits are based on the following weight and 

center of gravity limit data (landing gear down).

2,950 lb (takeoff

or landing) 

2,525 lb 

2,475 lb or less 

82.1

77.5

77.0

84.7

85.7

85.7

Forward

CG Limit

Weight

Condition

AFT

CG Limit

Moment

100 Weight

Baggage or 5th

Seat Occupant

Arm 140

 10

 20

 30

 40

 50

 60

 70

 80

 90

100

110

120

 14

 28

 42

 56

 70

 84

 98

112

126

140

154

168

182

Weight

Maximum

Moment

100

Minimum

Moment

100

1,800

1,808

1,817

1,825

1,834

1,843

1,851

1,860

1,868

1,877

1,885

1,894

1,903

1,911

1,920

1,928

1,937

1,945

1,954

1,963

1,971

1,980

1,988

1,997

2,005

2,014

2,023

2,031

2,040

2,048

2,100

2,110

2,120

2,130

2,140

2,150

2,160

2,170

2,180

2,190

2,200

2,210

2,220

2,230

2,240

2,250

2,260

2,270

2,280

2,290

2,300

2,310

2,320

2,330

2,340

2,350

2,360

2,370

2,380

2,390

1,617

1,625

1,632

1,640

1,648

1,656

1,663

1,671

1,679

1,686

1,694

1,702

1,709

1,717

1,725

1,733

1,740

1,748

1,756

1,763

1,771

1,779

1,786

1,794

1,802

1,810

1,817

1,825

1,833

1,840

Weight

Maximum

Moment

100

Minimum

Moment

100

2,057

2,065

2,074

2,083

2,091

2,100

2,108

2,117

2,125

2,134

2,143

2,151

2,160

2,168

2,176

2,184

2,192

2,200

2,208

2,216

2,224

2,232

2,239

2,247

2,255

2,263

2,271

2,279

2,287

2,295

2,303

2,311

2,319

2,326

2,334

2,342

2,350

2,358

2,366

2,374

2,381

2,389

2,397

2,405

2,413

2,421

2,426

2,436

2,444

2,452

3,460

2,468

2,475

2,483

2,491

2,499

2,400

2,410

2,420

2,430

2,440

2,450

2,460

2,470

2,480

2,490

2,500

2,510

2,520

2,530

2,540

2,550

2,560

2,570

2,580

2,590

2,600

2,610

2,620

2,630

2,640

2,650

2,660

2,670

2,680

2,690

2,700

2,710

2,720

2,730

2,740

2,750

2,760

2,770

2,780

2,790

2,800

2,810

2,820

2,830

2,840

2,850

2,860

2,870

2,880

2,890

2,900

2,910

2,920

2,930

2,940

2,950

1,848

1,856

1,863

1,871

1,879

1,887

1,894

1,092

1,911

1,921

1,932

1,942

1,953

1,963

1,974

1,984

1,995

2,005

2,016

2,026

2,037

2,048

2,058

2,069

2,080

2,090

2,101

2,112

2,123

2,133

2,144

2,155

2,166

2,177

2,188

2,199

2,210

2,221

2,232

2,243

2,254

2,265

2,276

2,287

2,298

2,309

2,320

2,332

2,343

2,354

2,365

2,377

2,388

2,399

2,411

2,422

Sample Loading Problem Weight Moment

 Basic empty weight 2,015 1,554

 Fuel main tanks (44 gal) 264 198

*Front seat passengers 300 254

*Rear seat passengers 190 230

 Baggage 30 42

 Total 2,799 2,278/100

* Interpolate or, as in this case, add appropriate numbers.

Empty Weight ~ 2,015

MOM/ 100 ~ 1,554

*Oil

Quarts Weight Moment

100 

 10 19 5

*Included in basic empty weight

BAGGAGE AREA

SEATING AREA

Figure 9-9. Loading schedule placard.

The same steps should be followed as in the computational 

method except the graphs provided will calculate the 

moments and allow the pilot to determine if the aircraft is 

loaded within limits. To determine the moment using the 

loading graph, find the weight and draw a line straight across 

until it intercepts the item for which the moment is to be 

calculated. Then draw a line straight down to determine the 

moment. (The red line on the loading graph represents the 

moment for the pilot and front passenger. All other moments 

were determined in the same way.) Once this has been done 

for each item, total the weight and moments and draw a line 

for both weight and moment on the CG envelope graph. If 

the lines intersect within the envelope, the aircraft is loaded 

within limits. In this sample loading problem, the aircraft is 

loaded within limits.

Table Method

The table method applies the same principles as the 

computational and graph methods. The information 

and limitations are contained in tables provided by the 

manufacturer. Figure 9-9 is an example of a table and a 

weight and balance calculation based on that table. In this 

problem, the total weight of 2,799 pounds and moment of 

2,278/100 are within the limits of the table.
9-10

Item Weight Arm Moment

Basic Empty Weight

Front Seat Occupants

3rd & 4th Seat Occupants 

Forward Facing

5th & 6th Seat Occupants

Nose Baggage

Aft Baggage

Subtotal

Fuel

Subtotal Ramp Weight

* Less Fuel for Start,

Taxi, and Takeoff

Subtotal

Takeoff Weight

Less Fuel to Destination

Actual Landing Weight

*Fuel for start, taxi, and takeoff is normally 24 pounds.

 3,230

 335

 350

 200

 100

 25

 4,240

 822

 5,062

 −24

 5,038

 −450

 4,588

292,315.0

 29,815.0

 44,100.0

 31,400.0

 1,000.0

4,575.0

 403,205.0

 92,886.0

 496,091.0

−2,712.0

493,379.0

 −50,850.0

 442,529.0

 CG 90.5

 89.0

 126.0

 157.0

 10.0

 183.0

 CG 95.1

 113.0

 CG 98.0

 113.0

 CG 97.9

 113.0

 CG 96.5

Zero Fuel Weight Max 4,400 pounds

Ramp Weight Max 5,224 pounds

Max Landing Weight 4,940 pounds

Figure 9-11. Sample weight and balance using an aircraft with a 

published zero fuel weight.

Item Weight Arm Moment

Licensed Empty Weight 1,011.9 68.6 69,393.0

Oil (6 quarts) 11.0 −31.0 −341.0

Fuel (18 gallons) 108.0 84.0 9,072.0

Fuel, Auxiliary (18 gallons) 108.0 84.0 9,072.0

Pilot 170.0 81.0 13,770.0

Passenger 170.0 81.0 13,770.0

Baggage 70.0 105.0 7,350.0

Total 1,648.9 122,086.0

CG 74.0

Figure 9-10. Sample weight and balance using a negative.

Computations With a Negative Arm

Figure 9-10 is a sample of weight and balance computation 

using an airplane with a negative arm. It is important to 

remember that a positive times a negative equals a negative, 

and a negative would be subtracted from the total moments.

Computations With Zero Fuel Weight

Figure 9-11 is a sample of weight and balance computation 

using an aircraft with a zero fuel weight. In this example, 

the total weight of the aircraft less fuel is 4,240 pounds, 

which is under the zero fuel weight of 4,400 pounds. If the 

total weight of the aircraft without fuel had exceeded 4,400 

pounds, passengers or cargo would have needed to be reduced 

to bring the weight at or below the max zero fuel weight.

Shifting, Adding, and Removing Weight

A pilot must be able to solve any problems accurately that 

involve the shift, addition, or removal of weight. For example, 

the pilot may load the aircraft within the allowable takeoff 

weight limit, then find a CG limit has been exceeded. The 

most satisfactory solution to this problem is to shift baggage, 

passengers, or both. The pilot should be able to determine 

the minimum load shift needed to make the aircraft safe for 

flight. Pilots should be able to determine if shifting a load to 

a new location will correct an out-of-limit condition. There 

are some standardized calculations that can help make these 

determinations.

Weight Shifting

When weight is shifted from one location to another, the 

total weight of the aircraft is unchanged. The total moments, 

however, do change in relation and proportion to the 

direction and distance the weight is moved. When weight is 

moved forward, the total moments decrease; when weight 

is moved aft, total moments increase. The moment change 

is proportional to the amount of weight moved. Since many 

aircraft have forward and aft baggage compartments, weight 

may be shifted from one to the other to change the CG. If 

starting with a known aircraft weight, CG, and total moments, 

calculate the new CG (after the weight shift) by dividing the 

new total moments by the total aircraft weight.

To determine the new total moments, find out how many 

moments are gained or lost when the weight is shifted. 

Assume that 100 pounds has been shifted from station 30 to 

station 150. This movement increases the total moments of 

the aircraft by 12,000 in-lb.

Moment when

at station 150 = 100 lb x 150 in = 15,000 in-lb

Moment when

at station 30 = 100 lb x 30 in = 3,000 in-lb

Moment change = [15,000 - 3,000] = 12,000 in-lb

By adding the moment change to the original moment (or 

subtracting if the weight has been moved forward instead of 

aft), the new total moments are obtained. Then determine the 

new CG by dividing the new moments by the total weight:

Total moments = 

616,000 in-lb + 12,000 in-lb = 628,000 in-lb

CG = 628,000 in-lb = 78.5 in

 8,000 lb 

The shift has caused the CG to shift to station 78.5.
9-11

Example

The change of CG is added to (or subtracted from when appropriate) 

the original CG to determine the new CG: 

77 + 1.5 = 78.5 inches aft of datum

The shifting weight proportion formula can also be used to determine 

how much weight must be shifted to achieve a particular shift of the CG. 

The following problem illustrates a solution of this type.

Weight shifted

Total weight

∆CG (change of CG)

Distance weight is shifted =

100

8,000

∆CG

120 =

∆CG = 1.5 in

Example

Weight to be shifted

Total weight

 CG

Distance weight is shifted =

Weight to be shifted

7,800 lb

Weight to be shifted

1.0 in

120 in =

= 65 lb

Given:

Aircraft total weight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7,800 lb

CG station. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81.5 in

Aft CG limit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80.5 in

Determine how much cargo must be shifted from the aft cargo compartment at station 150 to the forward cargo compartment at station 30 to

move the CG to exactly the aft limit.

Solution:

Example

Added weight

New total weight

∆CG

Distance between weight and old CG

∆CG

150 in − 80 in

=

140 lb

6,860 lb + 140 lb =

140 lb

7,000 lb = ∆CG70 in

CG = 1.4 in aft

Given:

Aircraft total weight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6,860 lb

CG station. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80.0 in

Determine the location of the CG if 140 pounds of baggage is added to

station 150.

Solution:

Add ∆CG to old CG

New CG = 80 in + 1.4 in = 81.4 in

Example

Weight removed

New total weight

∆CG

Distance between weight and old CG

∆CG

150 in − 80 in

=

100 lb

6,100 lb − 100 lb =

100 lb

6,000 lb = ∆CG70 in

CG = 1.2 in forward

Given:

Aircraft total weight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6,100 lb

CG station. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80.0 in

Determine the location of the CG if 100 pounds is removed from

station 150.

Solution: 

Subtract ∆CG from old CG

New CG = 80 in − 1.2 in = 78.8 in

A simpler solution may be obtained by using a computer 

or calculator and a proportional formula. This can be done 

because the CG will shift a distance that is proportional to 

the distance the weight is shifted.

Weight Addition or Removal

In many instances, the weight and balance of the aircraft will 

be changed by the addition or removal of weight. When this 

happens, a new CG must be calculated and checked against 

the limitations to see if the location is acceptable. This type 

of weight and balance problem is commonly encountered 

when the aircraft burns fuel in flight, thereby reducing the 

weight located at the fuel tanks. Most small aircraft are 

designed with the fuel tanks positioned close to the CG; 

therefore, the consumption of fuel does not affect the CG to 

any great extent.

The addition or removal of cargo presents a CG change 

problem that must be calculated before flight. The problem 

may always be solved by calculations involving total 

moments. A typical problem may involve the calculation 

of a new CG for an aircraft which, when loaded and ready 

for flight, receives some additional cargo or passengers just 

before departure time.

In the previous examples, the CG is either added or 

subtracted from the old CG. Deciding which to accomplish is 

best handled by mentally calculating which way the CG will 

shift for the particular weight change. If the CG is shifting 

aft, the CG is added to the old CG; if the CG is shifting 

forward, the CG is subtracted from the old CG.

Chapter Summary

Operating an aircraft within the weight and balance limits 

is critical to flight safety. Pilots must ensure that the CG is 

and remains within approved limits for all phases of a flight. 

Additional information on weight, balance, CG, and aircraft 

stability can be found in FAA-H-8083-1, Aircraft Weight 

and Balance Handbook. Those pilots flying helicopters or 

gyroplanes should consult the Rotorcraft Flying Handbook, 

FAA-H-8083-21, for specific information relating to aircraft 

type.
9-12