Flight Planning and Paperwork
During flight planning, the crew received several items of paperwork for the rescheduling of the service to include Karratha. The first Cabin Management (CM) summary likely contained information about 30 bags that had been offloaded from an earlier flight. The final CM summary provided to the flight crew contained incorrect information regarding the total number and weight of bags loaded onto the aircraft, but it matched the passengers' checked-in baggage.
Baggage Weight Discrepancy
It is likely that when entering data into the electronic load sheet, the crew used the baggage weight from the CM summary annotated "Acceptance not finalised" during the planning stage. The crosscheck of baggage weight entered into the electronic load sheet from the first CM summary (388 kg) against the final CM summary (365 kg) probably led the captain to incorrectly assume that the planned baggage weight was acceptable.
Limitations of the Load Information System
The Load Information System (LIS) displays the total number of bags and their distribution between cargo compartments, but it does not include the weight of baggage. Consequently, the LIS can be used for entering and crosschecking bag numbers but not for entering or crosschecking baggage weight.
Omission of Crosscheck
It is probable that the flight crew did not crosscheck the total number of bags on the LIS against the final CM summary.