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Weight and Balance. 2 3 Lesson Objectives At the conclusion of this lesson you will…  Understand why weight and balance is critical to safety of flight.

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Presentation on theme: "Weight and Balance. 2 3 Lesson Objectives At the conclusion of this lesson you will…  Understand why weight and balance is critical to safety of flight."— Presentation transcript:

1 Weight and Balance

2 2

3 3 Lesson Objectives At the conclusion of this lesson you will…  Understand why weight and balance is critical to safety of flight  Be familiar with the terms associated with weight and balance  Be familiar with the methods of calculating weight and balance  Understand the effect weight and balance has on aircraft performance

4 4

5 5 Importance of Weight and Balance  Aircraft are designed to be operated within specific Center of Gravity limits.  Wings can only produce so much lift. Weight in excess of what the wing is designed to carry is hazardous.  Increases in weight also effect the general performance.

6 6 Weight Terms  Empty Aircraft –Standard Empty Weight – weight of a standard airplane including unusable fuel, full operating fluids and full oil –Basic Empty Weight – Standard Empty Weight plus optional equipment  Starting Point of Weight and Balance

7 7

8 8 Weight Terms  Fuel –Usable Fuel – fuel which can be used for flight planning –Unusable Fuel – fuel which cannot be use in flight due to fuel tank design –6 lbs per gallon

9 9 Weight Terms  Useful Load – total usable fuel, passengers, and cargo –Maximum Ramp Weight – Basic Empty Weight = Useful Load  Payload – passengers and cargo –What essentially could be revenue generating

10 10 Weight Terms  Loaded Aircraft –Maximum Ramp Weight  Maximum allowable mass for ground operations  Assures ground maneuverability  Includes fuel for taxi, run-up and start –Maximum Takeoff Weight  Maximum allowable mass for initiation of takeoff roll  Failure to meet weight… –Maximum Landing Weight  Maximum allowable mass at touchdown  Generally limitation of landing gear –Baggage Compartment Limits  Could cause structural failure in floor

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12 12 Balance Terms  Weight –Force that acts straight down to the center of the Earth –Not always constant  Decreases with fuel burn

13 13 Balance Terms  Reference Datum –Reference base for location of components –Imaginary vertical plane –Location specified from manufacturer –Lies on longitudinal axis –Ex inches from wing leading edge

14 14 Balance Terms  Arm –Distance from the datum measured along the longitudinal axis  If located in front of datum, negative  If located in back of datum, positive

15 15 Balance Terms  Moment –Weight multiplied by its arm –Tendency of a mass to cause a rotation about the Center of Gravity –Force acting at that point

16 16 Balance Terms  Center of Gravity (CG) –Point of a mass through which gravity acts –Point where aircraft would balance if suspended –Point where all three axis intercept –Divide total moment of aircraft by weight of aircraft

17 17 Basic W&B Relationships 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, equipment, passengers, etc…The people are synonymous with the weight of fuel, equipment, passengers, etc… The fulcrum can be thought of as lift, supporting the entire mass.The fulcrum can be thought of as lift, supporting the entire mass. The datum can be considered the nose of the aircraft.The datum can be considered the nose of the aircraft.

18 18 Basic W&B Math  Moment = Weight X Arm  Center of Gravity =  Basic Empty Weight  + Payload  + Usable Fuel  =Ramp Weight  - Fuel used for start, taxi and run-up  = Takeoff Weight  - Fuel used for flight  = Landing Weight Sum of All Moments Gross Weight

19 19 Basic W&B Relationships  Balanced Condition

20 20 Basic W&B Relationships  Unbalanced Condition

21 21 Basic W&B Relationships  Forces Acting on an Aircraft in Flight   Center of Gravity forward of Center of Pressure  Downward force produced at tail to stabilize interaction of lift and weight

22 22 Basic W&B Relationships  Center of Gravity Limits

23 23 Results of Aircraft Overloading  Stall Speed  Increases  Takeoff and Landing Distance  Increases  Climb Rate  Reduced  Cruise Speed  Reduced  Fuel Consumption  Greater  Range and Endurance  Reduced  Stability  Increased

24 24 Results of a Forward CG  Longitudinal Stability becomes excessive –Rotation and Flare are more difficult  Takeoff Roll  Increased  Cruise Speed  Decreased –A greater tail down force must be produced. This is done aerodynamically, increasing drag.  Climb Rate  Reduced  Range and Endurance  Reduced  Stall Speed  Increased

25 25 Effects of an Aft CG Takeoff Roll  Reduced –Tendency to Over-Rotate  Cruise Speeds  Increased –Less tail down force, is less drag  Climb Rates  Increased  Fuel Consumption  Decreased  Range and Endurance  Increased  Stall Speeds  Reduced –Recovery hindered due to nose up tendency

26 Weight and Balance Documentation

27 27 POH Section 6  Section 6 contains… –Weight and Balance Calculation procedure for the aircraft –Basic Empty Weight and Moment of the aircraft –Changes to the Weight and Balance

28 28 Weight & Balance - Equipment List Revision

29 29 Weight & Balance - Equipment List Revision

30 30 Weight & Balance - Equipment List Revision

31 Weight and Balance Calculation

32 32 Weight & Balance Computations  Weight and balance information  Weight and balance formulas  Weight shift formulas  Weight and balance problem set up  Weight and balance information  Weight and balance formulas  Weight shift formulas  Weight and balance problem set up

33 33 Weight & Balance Computations Weight Shift Formulas

34 34 Miscellaneous W&B Solutions  Weight Shift Weight to be MovedDistance CG Moves Gross Weight Distance Weight Moves  Weight Addition / Deletion Weight to be Added/RemovedDistance CG Moves New Aircraft Gross Weight Distance Weight Moves = =

35 35 Weight & Balance Problem Set Up  Computation - - Piper Warrior  Computation - - Cessna P210  Graph - - Piper Arrow  Table - - Beech B33 Debonair  Computation - - Piper Warrior  Computation - - Cessna P210  Graph - - Piper Arrow  Table - - Beech B33 Debonair

36 36 Computation Method  This method uses the basic weight and balance formula to determine center of gravity.  This method can be used for most aircraft.  Extremely accurate, less arithmetic errors.

37 37 Computation Method  Procedure 1.Determine the Basic Empty Weight of the aircraft. 2.Find the moment of each weight to be carried. 3.Add all moments and all weights. 4.Divide the total moment by the total weight. This number is your Center of Gravity 5.Compare this number to the CG limits for the aircraft.

38 38 Weight & Balance - Piper Warrior For our first problem, we use a weight and balance form for a Piper Warrior. For our first problem, we use a weight and balance form for a Piper Warrior.

39 39 Step 1 –find the zero fuel condition Step 1 –find the zero fuel condition Weight & Balance - Piper Warrior

40 40 Piper Warrior Weight Arm Moment (lbs.) (in.) (lbs.-in.) Weight Arm Moment (lbs.) (in.) (lbs.-in.) Basic Empty Weight 1, ,850 Weight Arm Moment (lbs.) (in.) (lbs.-in.) Weight Arm Moment (lbs.) (in.) (lbs.-in.) Basic Empty Weight 1, ,850

41 41 Piper Warrior Weight Arm Moment Weight Arm Moment (lbs.) (in.) (lbs.-in.) (lbs.) (in.) (lbs.-in.) Basic Empty Weight 1, ,850 Pilot, Front Passengers ,370 Rear Passengers ,154 Weight Arm Moment Weight Arm Moment (lbs.) (in.) (lbs.-in.) (lbs.) (in.) (lbs.-in.) Basic Empty Weight 1, ,850 Pilot, Front Passengers ,370 Rear Passengers ,154

42 42 Piper Warrior Weight Arm Moment Weight Arm Moment (lbs.) (in.) (lbs.-in.) (lbs.) (in.) (lbs.-in.) Basic Empty Weight 1, ,850 Pilot, Front Passengers ,370 Rear Passengers ,154 Baggage (200 lb. Max) Zero Fuel Condition 2, ,374 Weight Arm Moment Weight Arm Moment (lbs.) (in.) (lbs.-in.) (lbs.) (in.) (lbs.-in.) Basic Empty Weight 1, ,850 Pilot, Front Passengers ,370 Rear Passengers ,154 Baggage (200 lb. Max) Zero Fuel Condition 2, ,374

43 43 Step 2 –find the ramp condition and takeoff condition –determine that it is within limits Step 2 –find the ramp condition and takeoff condition –determine that it is within limits Weight & Balance - Piper Warrior

44 44 Piper Warrior Weight Arm Moment Weight Arm Moment (lbs.) (in.) (lbs.-in.) (lbs.) (in.) (lbs.-in.) Zero Fuel Condition 2, ,374 Fuel (48 gallons max) ,365 Ramp Condition 2, ,739 Taxi, start, runup fuel Takeoff condition 2, ,074 Weight Arm Moment Weight Arm Moment (lbs.) (in.) (lbs.-in.) (lbs.) (in.) (lbs.-in.) Zero Fuel Condition 2, ,374 Fuel (48 gallons max) ,365 Ramp Condition 2, ,739 Taxi, start, runup fuel Takeoff condition 2, ,074

45 45

46 46 Step 3 –find the landing condition Step 3 –find the landing condition Weight & Balance - Piper Warrior

47 47 Piper Warrior Weight Arm Moment Weight Arm Moment (lbs.) (in.) (lbs.-in.) (lbs.) (in.) (lbs.-in.) Takeoff condition 2, ,074 Cruise fuel (30 gallons) ,100 Landing condition 2, ,974 Weight Arm Moment Weight Arm Moment (lbs.) (in.) (lbs.-in.) (lbs.) (in.) (lbs.-in.) Takeoff condition 2, ,074 Cruise fuel (30 gallons) ,100 Landing condition 2, ,974

48 48 Step 4 –confirm that landing weight & C.G. fall within limits Step 4 –confirm that landing weight & C.G. fall within limits Weight & Balance - Piper Warrior

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50 50 Weight & Balance - Cessna P210 Computation Method

51 51 Cessna P210  BEW: 2,632 lbs. (Moment 109,000)  Front Seat (170 lbs.)  Center Seat (160 and 150 lbs)  Aft Seat (200 and 170 lbs)  Baggage Area A (150 lbs)  Baggage Area B (0)

52 52 102

53 53 Zero Fuel Condition ItemWeightArmMoment BEW Front Seat Center Seat Aft Seat Baggage A Zero-Fuel

54 54 Ramp Condition  Add 64 gallons of fuel ItemWeightArmMoment Zero-Fuel Fuel Ramp Weight

55 55 Takeoff Condition  Run-up minus 16 lbs of fuel ItemWeightArmMoment Ramp Weight Run-up Takeoff

56 56

57 57

58 58 Shift a Passenger  Move the 200 pound passenger from the aft seat to the front seat.  Equation –Weight MovedDistance CG Moves –Total Weight Distance between CG Location

59 59 –Weight MovedDistance CG Moves –Total Weight Distance between CG Location  200 lbs???????????????????  4000 lbs(102-37) 65’  (65 x 200)/4000  13000/4000 = 3.25  – 3.25 = 49.64

60 60

61 61 Fuel Burn  2.5 hour flight at 20 gallons per hour ItemWeightArmMoment Takeoff Fuel Burn (2.5 x 20 x 6) Landing

62 62

63 63 Example  BEW  Front Seat  Center Seat190  Aft Seat  Baggage A10  Baggage B25

64 64 Chart Method  This method depends on charts provided by the manufacturer to determine the moments.  Accuracy of the chart method tends to decrease as the size of the aircraft increases.  Accuracy in general is generally within a few hundred pound – inches.  The procedure may vary from aircraft to aircraft.

65 65 Chart Method  Procedure (General) 1.Find the charts provided by the manufacturer in Section 6 of the POH. (These may or may not be provided) 2.Correlate the weights to the appropriate chart to determine the moment. 3.Add the moments determined from the charts and correlate them to the CG Limit chart.

66 66 Weight & Balance - Piper Arrow  Graph Method

67 67 PA28-R-201 ARROW  BEW lbs. (moment 147,695.8)  Pilot and Front Passenger lbs.  Rear passenger lbs.  Baggage lbs.

68 68

69 69  Moment –BEW - 147,695.8 –Front Seat - 30,000 –Back Seat - 25,000 –Baggage - 14,200 ItemWeightArmMoment BEW Front Pas Rear Pas Baggage Zero Fuel

70 70  Fuel (72 gallon maximum) –50 gallons  300 lbs.  Moment –29000

71 71 ItemWeightArmMoment Zero Fuel Fuel Ramp Weight Run-up Takeoff

72 72

73 73  Fuel used in flight –3 hours at 11.6 gallons per hour  34.8 gallons –208.8 lbs. –Moment - 20,000

74 74 ItemWeightArmMoment Takeoff Fuel Landing

75 75

76 76 Problem!  BEW  Front Pax400  Rear Pax150  Fuel200

77 Weight and Balance Computation Table Method Beech Debonair

78 78 Table Method  This method depends on tables provided by the manufacturer.  Moment data is provided for specific weights only.  Interpolation will be necessary to determine weights not specifically listed.  Accuracy is generally within a few hundred pound – inches.  This procedure may vary from aircraft to aircraft.

79 79 Table Method  Procedure 1.Find the tabular data provided in Section 6 of the POH. (These may or may not be provided) 2.Correlate the weight to the appropriate tables to determine the moment. 3.Add the moments determined from the tables and correlate them to the CG Limit chart.

80 80 Beech B33 Debonair  BEW lbs. (Moment 1584)  Front Seat ( Forward 170 lbs. and 200 lbs.)  Rear Seat (120 lbs. And 130 lbs)  Baggage (50 lbs.)

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84 84 Calculations ItemWeightArmMoment BEW Front Pax Rear Pax Baggage5070 Zero Fuel

85 85

86 86 Adding Fuel  Fuel (64 gallons maximum) –60 gallons  360 lbs.

87 87 Ramp Condition ItemWeightArmMoment Zero Fuel Fuel Ramp Weight Run-up-10-8 Takeoff Weight

88 88

89 89 Fuel Burn  3 hour flight (14.7 gallons per hour)  44.1 gallons –264 lbs.

90 90 Landing Condition ItemWeightArmMoment Takeoff Weight Fuel flight Landing Weight

91 91

92 92 Problem!!  BEW 1980 lbs. (Moment 1584)  Front Pax (Aft)190 And160  Rear Pax150  Baggage200  30 gallons of fuel


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