Section 21 (2) of the Transport Safety Investigation Act 2003 (TSI Act) empowers the Australian Transport Safety Bureau (ATSB) to discontinue an investigation into a transport safety matter at any time. Section 21 (3) of the TSI Act requires the ATSB to publish a statement setting out the reasons for discontinuing an investigation.

On 15 February 2011, the ATSB commenced an investigation into a pre-flight planning event that occurred at about 0017 Eastern Daylight-saving Time on 11 February 2011 and involved an Airbus A320-232 aircraft, registered VH-VNB. The initial report from the operating crew was that, prior to departure on the scheduled high capacity flight from Melbourne, Victoria to Perth, Western Australia, incorrect data was entered into the aircraft's flight management computer. The suspected 'error' was not detected by one of the flight crew until the aircraft was in the take-off roll. Subsequently, the second member of the flight crew reported that the speeds that were used were correct and were logical for the aircraft's weight and ambient conditions.

An initial examination of the available recorded data showed a consistent acceleration, rotation and climb with no abnormalities. The recorded speed at rotation correlated with that used for the flight and noted on the aircraft's data card. No equipment anomaly was recorded in the aircraft's technical log after the flight.

The ATSB's primary focus is on enhancing safety with respect to fare-paying passengers and, in particular, those transport safety matters that may present a significant threat to public safety or are the subject of significant public concern. In this instance, the contrasting flight crew recollections of the 'event' and the available data suggest that a transport safety matter as defined in Section 23 of the TSI Act may not have taken place.

The ATSB therefore considered there was limited potential to enhance transport safety by continuing this investigation, and has elected to discontinue it. However, the data already collected may be used by the ATSB for future statistical analysis and safety research purposes.