3. 33
Lesson ObjectivesLesson Objectives
At the conclusion of this lesson you will…At the conclusion of this lesson you will…
Understand why weight and balance is criticalUnderstand why weight and balance is critical
to safety of flightto safety of flight
Be familiar with the terms associated withBe familiar with the terms associated with
weight and balanceweight and balance
Be familiar with the methods of calculatingBe familiar with the methods of calculating
weight and balanceweight and balance
Understand the effect weight and balance hasUnderstand the effect weight and balance has
on aircraft performanceon aircraft performance
5. 55
Importance of Weight andImportance of Weight and
BalanceBalance
Aircraft are designed to be operatedAircraft are designed to be operated
within specific Center of Gravity limits.within specific Center of Gravity limits.
Wings can only produce so much lift.Wings can only produce so much lift.
Weight in excess of what the wing isWeight in excess of what the wing is
designed to carry is hazardous.designed to carry is hazardous.
Increases in weight also effect theIncreases in weight also effect the
general performance.general performance.
6. 66
Weight TermsWeight Terms
Empty AircraftEmpty Aircraft
Standard Empty Weight – weight of aStandard Empty Weight – weight of a
standard airplane including unusable fuel, fullstandard airplane including unusable fuel, full
operating fluids and full oiloperating fluids and full oil
Basic Empty WeightBasic Empty Weight – Standard Empty– Standard Empty
Weight plus optional equipmentWeight plus optional equipment
• Starting Point of Weight and BalanceStarting Point of Weight and Balance
8. 88
Weight TermsWeight Terms
FuelFuel
Usable Fuel – fuel which can be used for flightUsable Fuel – fuel which can be used for flight
planningplanning
Unusable Fuel – fuel which cannot be use inUnusable Fuel – fuel which cannot be use in
flight due to fuel tank designflight due to fuel tank design
6 lbs per gallon6 lbs per gallon
9. 99
Weight TermsWeight Terms
Useful Load – total usable fuel,Useful Load – total usable fuel,
passengers, and cargopassengers, and cargo
Maximum Ramp Weight – Basic Empty Weight = Useful LoadMaximum Ramp Weight – Basic Empty Weight = Useful Load
Payload – passengers and cargoPayload – passengers and cargo
What essentially could be revenue generatingWhat essentially could be revenue generating
10. 1010
Weight TermsWeight Terms
Loaded AircraftLoaded Aircraft
Maximum Ramp WeightMaximum Ramp Weight
• Maximum allowable mass for ground operationsMaximum allowable mass for ground operations
• Assures ground maneuverabilityAssures ground maneuverability
• Includes fuel for taxi, run-up and startIncludes fuel for taxi, run-up and start
Maximum Takeoff WeightMaximum Takeoff Weight
• Maximum allowable mass for initiation of takeoff rollMaximum allowable mass for initiation of takeoff roll
• Failure to meet weight…Failure to meet weight…
Maximum Landing WeightMaximum Landing Weight
• Maximum allowable mass at touchdownMaximum allowable mass at touchdown
• Generally limitation of landing gearGenerally limitation of landing gear
Baggage Compartment LimitsBaggage Compartment Limits
• Could cause structural failure in floorCould cause structural failure in floor
12. 1212
Balance TermsBalance Terms
WeightWeight
Force that acts straight down to the center ofForce that acts straight down to the center of
the Earththe Earth
Not always constantNot always constant
• Decreases with fuel burnDecreases with fuel burn
13. 1313
Balance TermsBalance Terms
Reference DatumReference Datum
Reference base for location of componentsReference base for location of components
Imaginary vertical planeImaginary vertical plane
Location specified from manufacturerLocation specified from manufacturer
Lies on longitudinal axisLies on longitudinal axis
Ex. 78.4 inches from wing leading edgeEx. 78.4 inches from wing leading edge
14. 1414
Balance TermsBalance Terms
ArmArm
Distance from the datum measured along theDistance from the datum measured along the
longitudinal axislongitudinal axis
• If located in front of datum, negativeIf located in front of datum, negative
• If located in back of datum, positiveIf located in back of datum, positive
15. 1515
Balance TermsBalance Terms
MomentMoment
Weight multiplied by its armWeight multiplied by its arm
Tendency of a mass to cause a rotation aboutTendency of a mass to cause a rotation about
the Center of Gravitythe Center of Gravity
Force acting at that pointForce acting at that point
16. 1616
Balance TermsBalance Terms
Center of Gravity (CG)Center of Gravity (CG)
Point of a mass through which gravity actsPoint of a mass through which gravity acts
Point where aircraft would balance ifPoint where aircraft would balance if
suspendedsuspended
Point where all three axis interceptPoint where all three axis intercept
Divide total moment of aircraft by weight ofDivide total moment of aircraft by weight of
aircraftaircraft
17. 1717
Basic W&B RelationshipsBasic W&B Relationships
For the next few examples…For the next few examples…
•
The seesaw is synonymous with the aircraft.The seesaw is synonymous with the aircraft.
•
The people are synonymous with the weight of fuel,The people are synonymous with the weight of fuel,
equipment, passengers, etc…equipment, passengers, etc…
•
The fulcrum can be thought of as lift, supporting theThe fulcrum can be thought of as lift, supporting the
entire mass.entire mass.
•
The datum can be considered the nose of the aircraft.The datum can be considered the nose of the aircraft.
18. 1818
Basic W&B MathBasic W&B Math
Moment = Weight X ArmMoment = Weight X Arm
Center of Gravity =Center of Gravity =
Basic Empty WeightBasic Empty Weight
+ Payload+ Payload
+ Usable Fuel+ Usable Fuel
=Ramp Weight=Ramp Weight
- Fuel used for start, taxi and run-up- Fuel used for start, taxi and run-up
= Takeoff Weight= Takeoff Weight
- Fuel used for flight- Fuel used for flight
= Landing Weight= Landing Weight
Sum of All Moments
Gross Weight
21. 2121
Basic W&B RelationshipsBasic W&B Relationships
Forces Acting on an Aircraft in FlightForces Acting on an Aircraft in Flight
www.aero.und.eduwww.aero.und.edu/multimedia/multimedia
Center of GravityCenter of Gravity
forward of Center offorward of Center of
PressurePressure
Downward forceDownward force
produced at tail toproduced at tail to
stabilize interactionstabilize interaction
of lift and weightof lift and weight
23. 2323
Results of Aircraft OverloadingResults of Aircraft Overloading
Stall SpeedStall Speed IncreasesIncreases
Takeoff and Landing DistanceTakeoff and Landing Distance IncreasesIncreases
Climb RateClimb Rate ReducedReduced
Cruise SpeedCruise Speed ReducedReduced
Fuel ConsumptionFuel Consumption GreaterGreater
Range and EnduranceRange and Endurance ReducedReduced
StabilityStability IncreasedIncreased
24. 2424
Results of a Forward CGResults of a Forward CG
Longitudinal Stability becomes excessiveLongitudinal Stability becomes excessive
Rotation and Flare are more difficultRotation and Flare are more difficult
Takeoff RollTakeoff Roll IncreasedIncreased
Cruise SpeedCruise Speed DecreasedDecreased
A greater tail down force must be produced. This is doneA greater tail down force must be produced. This is done
aerodynamically, increasing drag.aerodynamically, increasing drag.
Climb RateClimb Rate ReducedReduced
Range and EnduranceRange and Endurance ReducedReduced
Stall SpeedStall Speed IncreasedIncreased
25. 2525
Effects of an Aft CGEffects of an Aft CG
Longitudinally StabilityLongitudinally Stability ReducedReduced
Takeoff RollTakeoff Roll ReducedReduced
Tendency to Over-RotateTendency to Over-Rotate
Landing RollLanding Roll ReducedReduced
Tendency to Over-FlareTendency to Over-Flare
Cruise SpeedsCruise Speeds IncreasedIncreased
Less tail down force, is less dragLess tail down force, is less drag
Climb RatesClimb Rates IncreasedIncreased
Fuel ConsumptionFuel Consumption DecreasedDecreased
Range and EnduranceRange and Endurance IncreasedIncreased
Stall SpeedsStall Speeds ReducedReduced
Recovery hindered due to nose up tendencyRecovery hindered due to nose up tendency
27. 2727
POH Section 6POH Section 6
Section 6 contains…Section 6 contains…
Weight and Balance Calculation procedure forWeight and Balance Calculation procedure for
the aircraftthe aircraft
Basic Empty Weight and Moment of theBasic Empty Weight and Moment of the
aircraftaircraft
Changes to the Weight and BalanceChanges to the Weight and Balance
28. 2828
Equipment ListEquipment List
Contains all of the equipment installed inContains all of the equipment installed in
the aircraft, its location, and it’s weightthe aircraft, its location, and it’s weight
Format of Equipment Lists may varyFormat of Equipment Lists may vary
Located in the back of the POHLocated in the back of the POH
30. 3030
Weight &Weight &
Balance -Balance -
Equipment ListEquipment List
RevisionRevision
CENTER FOR AEROSPACE SCIENCES
UNIVERSITY OF NORTH DAKOTA
WEIGHT AND BALANCE, AND EQUIPMENT LIST REVISION
AIRCRAFT MODEL
N
SERIAL NO.
DATE
AMOUNT
NAME
CERTIFICATE NO.
E.W.
PREVIOUS EMPTYAIRPLANE
TOTAL ADDED OR SUBTRACTED
REVISED EMPTYAIRPLANE
USEFUL LOAD
DESCRIPTION WEIGHT
(LB)
ARM
(IN)
MOMENT
C.G. MOMENT
Jim Gilstad
OGSR092N
PA 28-161
142 ND
2841229
5-1-94
1 Fire Extinguisher +2.7 57.9 +156
1464.4
+2.7
1467.1
85.0
804.9
85.0
124469.5
+156.0
124625.5
31. 3131
Weight & Balance -Weight & Balance -
Equipment List RevisionEquipment List Revision
NAME
CERTIFICATE NO.
E.W. C.G. MOMENT
PREVIOUS EMPTY AIRPLANE
TOTALADDED OR SUBTRACTED
REVISED EMPTY AIRPLANE
USEFUL LOAD Jim Gilstad
OGSR092N
1464.4
+2.7
1467.1
85.0
804.9
85.0
124469.5
+156.0
124625.5
32. 3232
CENTER FORAEROSPACE SCIENCES
UNIVERSITY OF NORTH DAKOTA
WEIGHTAND BALANCE,AND EQUIPMENTLIST REVISION
AIRCRAFTMODEL
N
SERIAL NO.
DATE
AMOUNT
NAME
CERTIFICATE NO.
E.W.
PREVIOUS EMPTYAIRPLANE
TOTALADDED OR SUBTRACTED
REVISED EMPTYAIRPLANE
USEFUL LOAD
DESCRIPTION WEIGHT
(LB)
ARM
(IN)
MOMENT
C.G. MOMENT
JimGilstad
OGSR092N
PA 28-161
142 ND
2841229
5-1-94
1 Fire Extinguisher -2.7 57.9 -156
1467.1
-2.7
1464.4
84.9
867.6
1
124625.5
-156.0
124469.5
SUPERCEDED
5-1-94
Weight &Weight &
Balance -Balance -
Equipment ListEquipment List
RevisionRevision
34. 3434
Weight & BalanceWeight & Balance
ComputationsComputations
Weight and balance informationWeight and balance information
Weight and balance formulasWeight and balance formulas
Weight shift formulasWeight shift formulas
Weight and balance problem set upWeight and balance problem set up
38. 3838
Computation MethodComputation Method
This method uses the basic weight andThis method uses the basic weight and
balance formula to determine center ofbalance formula to determine center of
gravity.gravity.
This method can be used for most aircraft.This method can be used for most aircraft.
Extremely accurate, less arithmetic errors.Extremely accurate, less arithmetic errors.
39. 3939
Computation MethodComputation Method
ProcedureProcedure
1.1. Determine the Basic Empty Weight of theDetermine the Basic Empty Weight of the
aircraft.aircraft.
2.2. Find the moment of each weight to beFind the moment of each weight to be
carried.carried.
3.3. Add all moments and all weights.Add all moments and all weights.
4.4. Divide the total moment by the total weight.Divide the total moment by the total weight.
This number is your Center of GravityThis number is your Center of Gravity
5.5. Compare this number to the CG limits for theCompare this number to the CG limits for the
aircraft.aircraft.
40. 4040
Weight & Balance -Weight & Balance -
Piper WarriorPiper Warrior
For our firstFor our first
problem, weproblem, we
use a weightuse a weight
and balanceand balance
form for aform for a
PiperPiper
Warrior.Warrior.
41. 4141
Step 1Step 1
find the zero fuel conditionfind the zero fuel condition
Weight & Balance -Weight & Balance -
Piper WarriorPiper Warrior
42. 4242
Piper WarriorPiper Warrior
Weight Arm MomentWeight Arm Moment
(lbs.) (in.) (lbs.-(lbs.) (in.) (lbs.-
in.)in.)
Basic Empty WeightBasic Empty Weight 1,5001,500
128,850128,850
43. 4343
Piper WarriorPiper Warrior
Weight Arm MomentWeight Arm Moment
(lbs.)(lbs.) (in.) (lbs.-in.)(in.) (lbs.-in.)
Basic Empty WeightBasic Empty Weight 1,5001,500 128,850128,850
Pilot, Front Passengers 340Pilot, Front Passengers 340 80.5 27,37080.5 27,370
Rear PassengersRear Passengers 340340 118.1 40,154118.1 40,154
44. 4444
Piper WarriorPiper Warrior
Weight Arm MomentWeight Arm Moment
(lbs.)(lbs.) (in.) (lbs.-in.)(in.) (lbs.-in.)
Basic Empty WeightBasic Empty Weight 1,5001,500 128,850128,850
Pilot, Front Passengers 340Pilot, Front Passengers 340 80.5 27,37080.5 27,370
Rear PassengersRear Passengers 340340 118.1 40,154118.1 40,154
Baggage (200 lb. Max)Baggage (200 lb. Max)
Zero Fuel ConditionZero Fuel Condition 2,1802,180 196,374196,374
45. 4545
Step 2Step 2
find the ramp condition andfind the ramp condition and
takeoff conditiontakeoff condition
determine that it is within limitsdetermine that it is within limits
Weight & Balance -Weight & Balance -
Piper WarriorPiper Warrior
53. 5353
Cessna P210Cessna P210
BEW: 2,632 lbs. (Moment 109,000)BEW: 2,632 lbs. (Moment 109,000)
Front Seat (170 lbs.)Front Seat (170 lbs.)
Center Seat (160 and 150 lbs)Center Seat (160 and 150 lbs)
Aft Seat (200 and 170 lbs)Aft Seat (200 and 170 lbs)
Baggage Area A (150 lbs)Baggage Area A (150 lbs)
Baggage Area B (0)Baggage Area B (0)
60. 6060
Shift a PassengerShift a Passenger
Move the 200 pound passenger from theMove the 200 pound passenger from the
aft seat to the front seat.aft seat to the front seat.
EquationEquation
Weight MovedWeight Moved Distance CG MovesDistance CG Moves
Total WeightTotal Weight Distance between CG LocationDistance between CG Location
61. 6161
Weight MovedWeight Moved Distance CG MovesDistance CG Moves
Total WeightTotal Weight Distance between CG LocationDistance between CG Location
200 lbs200 lbs ??????????????????????????????????????
4000 lbs4000 lbs (102-37) 65’(102-37) 65’
(65 x 200)/4000(65 x 200)/4000
13000/4000 = 3.2513000/4000 = 3.25
52.89 – 3.25 = 49.6452.89 – 3.25 = 49.64
65. 6565
ExampleExample
BEWBEW 26322632 109000109000
Front SeatFront Seat 150 + 210150 + 210
Center SeatCenter Seat 190190
Aft SeatAft Seat 150 + 190150 + 190
Baggage ABaggage A 1010
Baggage BBaggage B 2525
66. 6666
Chart MethodChart Method
This method depends on charts provided by theThis method depends on charts provided by the
manufacturer to determine the moments.manufacturer to determine the moments.
Accuracy of the chart method tends to decreaseAccuracy of the chart method tends to decrease
as the size of the aircraft increases.as the size of the aircraft increases.
Accuracy in general is generally within a fewAccuracy in general is generally within a few
hundred pound – inches.hundred pound – inches.
The procedure may vary from aircraft to aircraft.The procedure may vary from aircraft to aircraft.
67. 6767
Chart MethodChart Method
Procedure (General)Procedure (General)
1.1. Find the charts provided by the manufacturerFind the charts provided by the manufacturer
in Section 6 of the POH. (These may or mayin Section 6 of the POH. (These may or may
not be provided)not be provided)
2.2. Correlate the weights to the appropriateCorrelate the weights to the appropriate
chart to determine the moment.chart to determine the moment.
3.3. Add the moments determined from theAdd the moments determined from the
charts and correlate them to the CG Limitcharts and correlate them to the CG Limit
chart.chart.
75. 7575
Fuel used in flightFuel used in flight
3 hours at 11.6 gallons per hour3 hours at 11.6 gallons per hour
• 34.8 gallons34.8 gallons
208.8 lbs.208.8 lbs.
Moment - 20,000Moment - 20,000
79. Weight and BalanceWeight and Balance
ComputationComputation
Table MethodTable Method
Beech DebonairBeech Debonair
80. 8080
Table MethodTable Method
This method depends on tables provided by theThis method depends on tables provided by the
manufacturer.manufacturer.
Moment data is provided for specific weightsMoment data is provided for specific weights
only.only.
Interpolation will be necessary to determineInterpolation will be necessary to determine
weights not specifically listed.weights not specifically listed.
Accuracy is generally within a few hundredAccuracy is generally within a few hundred
pound – inches.pound – inches.
This procedure may vary from aircraft to aircraft.This procedure may vary from aircraft to aircraft.
81. 8181
Table MethodTable Method
ProcedureProcedure
1.1. Find the tabular data provided in Section 6 ofFind the tabular data provided in Section 6 of
the POH. (These may or may not bethe POH. (These may or may not be
provided)provided)
2.2. Correlate the weight to the appropriate tablesCorrelate the weight to the appropriate tables
to determine the moment.to determine the moment.
3.3. Add the moments determined from theAdd the moments determined from the
tables and correlate them to the CG Limittables and correlate them to the CG Limit
chart.chart.