Data input errors continue to be a problem in aviation, with three recent incidents highlighting the need for greater attention to detail.
In two instances, involving a Boeing 737 and an Airbus A330, the correct loading weight was not supplied to the flight crews, prior to departure.
Incident No.1
Handlers in Bali miscalculated the number of bags loaded onto a commercial Boeing 737 flight to Melbourne. The total number of bags loaded was 189, instead of 93, with an estimated additional weight of about 1,600 kg.
The load control team leader assessed the additional baggage weight was acceptable, that adequate fuel had been uploaded to cater for the extra weight and elected not to advise the flight crew of the discrepancy.
At the time of the occurrence there was no formal procedure to advise flight crew of a loadsheet discrepancy. However, if the flight crew were advised of loadsheet discrepancy in-flight, it is envisaged the additional weight figure would have been used to modify the approach speeds that had been generated, based on the weight entered into the flight management computer prior to departure. For an extra weight of 1,600 kg, the captain reported the approach speeds would normally increase by about 1-2 kt.
The flight arrived safely.
Second incident
In the second incident, involving an Airbus A330 flying from Perth to Brisbane, ground staff at Brisbane discovered an unlisted cargo weighing 1,467 kg that was supposed to have been offloaded in Perth.
As a result of both these incidents, the airline took several steps, including refresher training, to remedy the situation.
Incident No. 3
Loading of freight caused the pilot of a Fairchild SA227 to reject a take-off at Rockhampton.
Passing the take-off safety speed (V1), as the pilot increased the back pressure on the control yoke to rotate the aircraft for take-off, the control column felt heavy and the aircraft nose wheel did not lift off the ground. The pilot continued to increase the back trim and back pressure on the control yoke and the ‘out of trim’ warning sounded.
After taxiing the aircraft back to the bay, the pilot requested the freight be re-weighed. He recalculated the aircraft weight and balance with the actual freight distribution and found the centre of gravity slightly more forward than the original load sheet position.
Overall, the actual freight loaded weighed about 30 kg more than that stated on the load plan. One of the aircraft’s freight ‘zones’ was loaded with 72 kg more than the placard maximum weight for that zone. A revised trim sheet was prepared using the re-weigh information and found that the aircraft was within the centre of gravity limits for the proposed flight with a centre of gravity slightly forward of the original calculated position.
Following the incident, the operator advised the ATSB it was taking several safety actions, including investigating the management of ground handling and the manner in which aircraft are loaded at all ports.
All three incidents highlight the ATSB’s broad safety concerns about data input errors, such as incorrect loading figures. The consequences of these errors can include a range of aircraft handling and performance issues.
- Read the investigation reports in the ATSB’s latest short investigation bulletin issue 36.
- More information about data input errors and the ATSB’s other transport safety priorities can be found on the ATSB’s SafetyWatch page.
- Data input errors video