

Weight and Balance
Weight and Balance LimitationsWeight LimitationsHBIWF (the occurrence aircraft) was to be operated within the following weight limits: Table: HBIWF Weight Limits
Balance LimitationsThe C of G limits given in the load index below are valid up to the maximum TOW with landing gear extended. (See chart of "Actual loaded index ZFW  loaded index TOW.") Lateral loading is restricted by a maximum unsymmetrical fuel load of 1 800 kg. Cargo Compartment LimitsThe MD11 has five cargo compartments. The configuration used for SR 111 is Swissair unit load version 260, depicted below. (See illustration of "MD11 cargo compartments.") Table: Cargo Compartments and Unit Load Version 260
Aircraft Empty WeightsStructure WeightSwissair defines the structure weight as the weight of the aircraft including furnishings and loose equipment. Basic Empty WeightSwissair defines the basic empty weight as the combined structure weight and standard fluid weights. The basic empty weight for HBIWF (the occurrence aircraft) was as follows: Table: HBIWF Empty Weight
Basic WeightSwissair's weight control system uses average basic weights for groups of the same aircraft type and configuration. HBIWF was in the 131 925 kg basic weight group. Dry Operating WeightSwissair defines the dry operating weight as the basic weight plus operational items, including crew members, their baggage, and pantry items (e.g., galley, bar, food, and beverages). Swissair uses standard weights for crew members (90 kg each); the pantry weight is based on the style of pantry. SR 111 had 14 crew members and pantry code M. The dry operating weight for HBIWF was as follows: Table: HBIWF Dry Operating Weight
Cargo Weight and AllocationThe following cargo weights and allocations for SR 111 were provided by Swissair and verified during the investigation based on collected waybills. Table: SR 111 Cargo Weights and Allocations
Passenger Weight and Allocation(See illustration of "Passenger sections.") The tables below detail the number of passengers assigned seats in each section, the distribution of passengers by gender and age, and standard passenger weights used in load calculations. Table: Passenger Summary from Passenger Manifest
Table: Passenger Summary from Postaccident Review
Table: Swissair Standard Passenger Weights
Fuel Weight and AllocationAllied Fuels fuelled the aircraft with JetA fuel while it was parked at the gate at 2340. The total fuel weight was as follows: Table: SR 111 Total Fuel Weight
The flight plan indicated that SR 111 would use 1 000 kg of fuel for taxi and 49 600 kg for the trip. The actual taxi fuel used, as recorded on the FDR, was 720 kg. The takeoff fuel was estimated at 64 300 kg. The aircraft taxied with a total fuel load of 65 300 kg. A fuel density of 0.812 kg/L was used for SR 111 weight and balance calculations. Aircraft Loading ProcedurePassenger Boarding Procedure
Cargo Loading Procedure
Load Sheets
HBIWF Weight and Balance Calculations SummaryWeight CalculationThe information provided by Swissair indicated that the actual dry operating weight was 137 713 kg. The cargo weight was calculated by Swissair as 21 125 kg. Calculations performed during the investigation indicated that the total weight of the cargo, including passenger baggage as determined by waybills and standard weights, was 20 927 kg. While the 198 kg difference in cargo weight could not be resolved using the waybills provided, this difference represents less than 0.1% of the TOW. From an aircraft loading standpoint, this difference is negligible. Swissair calculated the passenger weight by multiplying the standard weight of 84 kg by the total number of passengers, excluding infants. Calculations performed during the investigation determined the following weights: Table: Weights
The load control computer calculated the estimated TOW of SR 111 to be 241 147 kg. A detailed calculation performed after the occurrence revealed that the actual TOW was 241 112 kg. The 35 kg difference is negligible. Both weights are within the maximum structural limits. Balance CalculationThe load control computer calculated the C of G to be 19.8% MAC. Using the balance table, the C of G was manually calculated to be 20.0% MAC. Both of these figures are well within the balance limits. Final Load Sheet(See copy of "Final load sheet.") [1] Limitation to prevent flaps from being overstressed when selecting landing flaps in flight at weights in excess of normal landing weights. [2] There is a difference between the Passenger Manifest and the Postaccident Review of the passengers by gender. This is attributed to the ticketing information. The passenger names were correct, but the gender was incorrect on the manifest. Gender information is used for weight calculations. Swissair used the same standard weight for males and females; therefore, the difference in the gender was inconsequential. [3] There were two infants who were not ticketed or assigned a seat, but who were included in the load control. 
