Weight and Balance

weight and balance distribution prior to takeoff are runway Item Weight Arm Moment length, runway surface, runway slope, surface wind, and the Aircraft Empty Weight 2,100 78.3 164,430 presence of obstacles. These factors may require a reduction Front Seat Occupants 340 85.0 28,900 in or redistribution of weight prior to flight. Rear Seat Occupants 350 121.0 42,350 Fuel 450 75.0 33,750 Some aircraft are designed so that it is difficult to load them Baggage Area 1 80 150.0 12,000 in a manner that places the CG out of limits. These are usually small aircraft with the seats, fuel, and baggage areas Total 3,320 281,430 281,430 ÷ 3,320 = 84.8 located near the CG limit. Pilots must be aware that while within CG limits these aircraft can be overloaded in weight. Figure 10-5. Example of weight and balance computations. 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 84.8 is within the 78–86 inch range; therefore, the aircraft is exceeded. Because of the effects of an out-of-balance or loaded within limits. overweight condition, a pilot should always be sure that an aircraft is properly loaded. Graph Method Another method for determining the loaded weight and CG is Determining Loaded Weight and CG the use of graphs provided by the manufacturers. To simplify There are various methods for determining the loaded weight calculations, the moment may sometimes be divided by 100, and CG of an aircraft. There is the computational method as 1,000, or 10,000. [Figures 10-6, 10-7, and 10-8] well as methods that utilize graphs and tables provided by Front seat occupants....................................340 pounds the aircraft manufacturer. Rear seat occupants ......................................300 pounds Computational Method Fuel .................................................................40 gallons The following is an example of the computational method Baggage area 1 ...............................................20 pounds involving the application of basic math functions. Aircraft Allowances: The same steps should be followed in the graph method as Maximum gross weight......................3,400 pounds were used in the computational method except the graphs provided will calculate the moments and allow the pilot to CG range.............................................78–86 inches determine if the aircraft is loaded within limits. To determine Given: the moment using the loading graph, find the weight and draw Weight of front seat occupants.............340 pounds a line straight across until it intercepts the item for which the moment is to be calculated. Then draw a line straight down Weight of rear seat occupants..............350 pounds to determine the moment. (The red line on the loading graph Fuel...........................................................75 gallons in Figure 10-7 represents the moment for the pilot and front Weight of baggage in area 1....................80 pounds passenger. All other moments were determined the same 1. List the weight of the aircraft, occupants, fuel, and baggage. Remember that aviation gas (AVGAS) Sample Loading Problem Weight (lb) Moment (in-lb/1,000) weighs 6 pounds per gallon and is used in this 1. Basic empty weight (Use data pertaining example. to aircraft as it is presently equipped) includes unusable fuel and full oil 1,467 57.3 2. Enter the moment for each item listed. Remember 2. Usable fuel (At 6 lb/gal) “weight x arm = moment.” Standard tanks (40 gal maximum) 240 11.5 Long range tanks (50 gal maximum) 3. Find the total weight and total moment. Integral tanks (62 gal maximum) Integral reduced fuel (42 gal) 4. To determine the CG, divide the total moment by the 3. Pilot and front passenger (Station 34 total weight. to 46) 340 12.7 4. Rear passengers 300 21.8 NOTE: The weight and balance records for a particular 5. Baggage area 1 or passenger on child’s seat (Station 82 to 108, 120 lb maximum) 20 1.9 aircraft provide the empty weight and moment, as well as the 6. Baggage area 2 information on the arm distance. [Figure 10-5] (Station 108 to 142, 50 lb maximum) 7. Weight and moment 2,367 105.2 The total loaded weight of 3,320 pounds does not exceed the maximum gross weight of 3,400 pounds, and the CG of Figure 10-6. Weight and balance data. 10-7