3.06 Weight & Balance

1. Ground School 3.06 Weight & Balance

2. 3.06 Importance of Weight Almost every aspect of performance is influenced by the weight of the aircraft and its contents. An overweight airplanewill has : • longer takeoff run • higher takeoff speed • lower angle and rate of climb • lower cruising speed • shorter range • higher stalling speed • longer landing roll

3. 3.06 Importance of Weight • Loading an airplane too heavy can dangerously decrease its performance, and increase the risk of structural damage. • Airplane manufacturers do extensive testing to establish safe limits for airplane loading. Most common limits are maximum takeoff and landing weights.

4. 3.06 Importance of Balance • Center of gravity (CG) : the imaginary point where the aircraft would balance if suspended • CG is critical to an airplane’s stability and elevator effectiveness. • CG limits are the forward and aft center of gravity locations within which the aircraft must be operated at a given weight.

5. 3.06 Weight And Balance TermsEmpty Airplane • Center of Gravity • CG Limits • Reference datum • Arm and Moment

6. 3.06 Weight And Balance Terms • Reference datum : the location from which all horizontal distances are measured for weight and balance purposes • Arm : distance from the datum, measurements aft of the datum are generally positive numbers, while those forward of the datum are generally negative numbers ( Fuselage station ; F.S. is another term for the arm) • Moment : a weight multiplied by an arm

7. 1 in. 2 in. 10 lbs 5 lbs 3.06 Aircraft Weight and Balance WEIGHT X ARM = MOMENT

8. 3.06 Weight And Balance TermsEmpty Airplane • Center of Gravity • CG Limits • Reference datum • Arm and Moment • Basic empty weight • Licensed empty weight • Unusable fuel

9. 3.06 Weight And Balance TermsEmpty Airplane • Basic empty weight : weight of airplane + equipment + unusable fuel + full engine oil • Licensed empty weight : weight of airplane + equipment + unusable fuel + full engine oil + undrainable oil • Unusable fuel : small amount of fuel in tanks that cannot be used in flight or drained on ground

10. 3.06 Weight And Balance TermsLoaded Airplane • Ramp Weight • Takeoff Weight • Landing Weight • Total Weight • Payload • Useful Load

11. 3.06 Weight And Balance TermsLoaded Airplane • Ramp Weight : airplane loaded for flight prior to engine start • Takeoff Weight : Ramp Weight – fuel burned during start & runup & taxi • Landing Weight : Takeoff Weight – fuel burned enroute

12. 3.06 Weight And Balance TermsLoaded Airplane • Total Weight : (Gross Wight) weight of airplane and everything carried in it • Payload : weight of only passengers, baggage and cargo • Useful Load : Payload + weight of flight crew and useable fuel

13. 3.06 Methods For Calculating Total Weight And CG • Table • Graph Computation

14. 3.06 Calculating the position of the CG - + 5 in. Ref Line 10 lbs 10 lbs 5 in. 15 in. W X A = M 10 lbs. X - 5 in = - 50 in lbs. 10 lbs. X + 15 in = +150 in lbs. 20 lbs. (W) +100 in lbs. Average Arm = +100/20 + 5 in

15. 3.06 Calculating the position of the CG - + 10 in. Reference Line 10 lbs 10 lbs 20 in. 30 in. W X A = M 10 lbs. X 10 in = +100 in lbs. 10 lbs. X 30 in = +300 in lbs. 20 lbs. (W) +400 in lbs. Average Arm = +400/20 + 20 in

16. 3.06 Calculating the position of the CG on an airplane Reference Datum - + 23 in. 10 in. 50 10 100 9 in. 10.18 in. 100 lbs. X 9 in = 900 in lbs 50 lbs. X 10 in = 500 in lbs. 10 lbs. X 23 in = 230 in lbs. 160 lbs. (W) 1630 in lbs. Average Arm = 1630/160 10.18 in

17. Empty Airplane: Arm: 70 inches Weight: 1,150 pounds Pilot: Arm: 73 inches Weight: 135 pounds Weight Arm Moment Empty Airplane 1,150 pounds X 70 inches = 80,850 pounds - inches Pilot 135 pounds X 73 inches = 9,855 pounds - inches Total 1,285 pounds 90,355 pounds - inches Total Moment Total Weight 90,355 pounds - inches 1285 pounds = 70.3 inches = CG Arm 3.06 Calculating the position of the CG on an airplane

18. 3.06 Methods For Calculating Total Weight and CG • Computation • Graph Table

20. 3.06 Methods For Calculating Total Weight and CG • Computation • Table Graph

21. Fuel Pilot and Passenger Rear Passenger(s) Baggage 3.06 Methods For Calculating Total Weight And CG Add all the amounts to obtain ramp moment.

22. Ramp Weight Ramp Moment 3.06 Center Of Gravity Moment Envelope Now what?

23. Ramp Weight Ramp CG 3.06 CG Limits Divide total moment by total weight to get CG.

24. 3.06 Weight Shift Formula Can be used to calculate the amount of weight that must be moved a specific distance or to determine the distance a specific weight would need to move to bring the CG within approved limits

25. 162 Pounds GROSS WEIGHT MOMENT LIMITS 3500 2600 2700 2800 2900 82.1 86.7 3400 2500 3300 F33A & F33C UTILITY CATEGORY LIMITS 2400 3200 3100 2300 3000 2200 2900 2100 2800 MOMENT / 100 - in. lbs Distance CG Moved Distance Between CG Arms Weight Moved Weight of Airplane 2000 = WEIGHT - POUNDS 2700 1900 2600 162 pounds 2,500 Pounds X 36 inches 2500 = 1800 2400 1700 2300 162 x 36 2,500 X = 1600 2200 2100 F33C ACROBATIC CATEGORY LIMITS X = 2.3 inches 2000 3.06 Weight Shift Formula Weight MovedDistance CG Move Weight of A/C Distance Between Arms

26. 3.06 Effects of increasing weights • Takeoff Distance • Landing Distance • Climbouts • True Airspeed Longer distance required Longer distance required Angle reduced Performance reduced Reduced

27. 3.06 Effects Of Moving CG Aft • Rotation • Flare • Stability • True Airspeed Too quick Too quick Less stable Faster

29. This could be you.