The Boeing 747 departed Cairns with a load sheet showing its take-off weight as 316,500 kg and its landing weight at Narita as 241,500 kg. During descent, company staff at Narita advised the crew to amend the aircraft's landing weight to 243,200 kg, the difference being due to 1,850 kg of cargo stowed in position 11 that had been recorded incorrectly.
Company staff identified a unit load device (ULD) weighing 950 kg, which had been packed in Sydney and transported to Cairns. At Cairns, the weight of the ULD was wrongly recorded as 1,850 kg. The reason for the error was not established, but it was possible that loading staff at Cairns may have pulled an old weight tag from the ULD tag pouch and noted the weight written on it.
The incorrect weight of 1,850 kg was then transcribed as 185 kg onto a `deadweight statement' (baggage and cargo weight) which was sent to Load Control three hours before scheduled departure. Coincidentally, 185 kg was the weight of an empty ULD. The load controller used 185 kg as the ULD weight in preparing the Load Instruction Report (LIR) for the Cairns loading staff, but they did not detect the discrepancy between the ULD tag weight (1,850 kg) and the LIR weight (185 kg). As the load controller had used 185 kg in the load calculations, both the Provisional Load sheet and the Final Load sheet understated the aircraft gross weight.
While the aircraft was in transit, company staff at Narita queried the ULD weight with the load controller, who then contacted the Cairns freight staff. Three hours before the aircraft was due to land, the freight staff sent a revised deadweight statement to the load controller, showing the ULD weight as 1,850 kg. The load controller then recalculated the load weight and passed this to the company staff at Narita, who in turn advised the crew to increase the aircraft landing weight by 1,700 kg. As the actual weight of the ULD was 950 kg, the revised landing weight overstated the true landing weight by 750 kg.
Since the occurrence, the company Freight Branch has issued a reminder to freight terminal staff to remove old weight tags from ULDs and has asked the Cairns freight staff to take action to prevent incorrect completion of deadweight statement forms. In addition, the Ramp Training and Safety Co-ordinator at Cairns has issued a notice to loading staff to check all weights on ULD tags against the weights stated on the LIR.