At 22:31 local time, an Airbus A340-500 aircraft, registered A6-ERG, commenced the takeoff roll on runway 16 at Melbourne Airport (MEL) on a scheduled, passenger flight (EK407) to Dubai (DXB), United Arab Emirates. The takeoff was planned as a reduced-power takeoff and the first officer was the handling pilot for the departure. At 22:31:53, the captain called for the first officer to rotate. The first officer attempted to rotate the aircraft, but it did not respond immediately with a nose-up pitch. The captain again called ‘rotate’ and the first officer applied a greater nose-up command. The nose of the aircraft was raised and the tail made contact with the runway surface, but the aircraft did not begin to climb. The captain then selected TOGA on the thrust levers, the engines responded immediately, and the aircraft commenced a climb. The crew notified air traffic control of the tail strike and that they would be returning to Melbourne. While reviewing the aircraft’s performance documentation in preparation for landing, the crew noticed that a takeoff weight, which was 100 tonnes below the actual takeoff weight of the aircraft, had inadvertently been used when completing the takeoff performance calculation. The result of that incorrect takeoff weight was to produce a thrust setting and takeoff reference speeds that were lower than those required for the actual aircraft weight. The aircraft subsequently landed at Melbourne with no reported injuries. The tail strike resulted in substantial damage to the tail of the aircraft and damaged some airport lighting and the instrument landing system. As a result of the accident, the aircraft operator has advised the Australian Transport Safety Bureau that it is reviewing a number of procedures including human factors involved in takeoff performance data entry. CONTRIBUTING SAFETY FACTORS: – The first officer inadvertently entered the incorrect take-off weight into the electronic flight bag to calculate the take-off performance parameters for the flight. – The captain was distracted while checking the take-off performance figures in the electronic flight bag, which resulted in him not detecting the incorrect take-off weight. – During the pre-departure phase, the flight crew did not complete all of the tasks in the standard operating procedures, which contributed to them not detecting the error. – When conducting the loadsheet confirmation procedure, the first officer called out 362.9 tonnes as the FLEX take-off weight, rather than the 262.9 tonnes that was recorded on the master flight plan, which removed an opportunity for the captain to detect the error. – The first officer changed the first digit of the FLEX take-off weight on the master flight plan during the loadsheet confirmation procedure, believing it had been transcribed incorrectly, which removed an opportunity for the flight crew to detect the error. – The lack of a designated position in the pre-flight documentation to record the green dot speed precipitated a number of informal methods of recording that value, lessening the effectiveness of the green dot check within the loadsheet confirmation procedure. [Minor safety issue] – The flight crew’s mixed fleet flying routinely exposed them to large variations in take-off weights and take-off performance parameters, which adversely influenced their ability to form an expectation of the ‘reasonableness’ of the calculated take-off performance parameters CONTRIBUTING SAFETY FACTORS: – The first officer inadvertently entered the incorrect take-off weight into the electronic flight bag to calculate the take-off performance parameters for the flight. – The captain was distracted while checking the take-off performance figures in the electronic flight bag, which resulted in him not detecting the incorrect take-off weight. – During the pre-departure phase, the flight crew did not complete all of the tasks in the standard operating procedures, which contributed to them not detecting the error. – When conducting the loadsheet confirmation procedure, the first officer called out 362.9 tonnes as the FLEX take-off weight, rather than the 262.9 tonnes that was recorded on the master flight plan, which removed an opportunity for the captain to detect the error. – The first officer changed the first digit of the FLEX take-off weight on the master flight plan during the loadsheet confirmation procedure, believing it had been transcribed incorrectly, which removed an opportunity for the flight crew to detect the error. – The lack of a designated position in the pre-flight documentation to record the green dot speed precipitated a number of informal methods of recording that value, lessening the effectiveness of the green dot check within the loadsheet confirmation procedure. [Minor safety issue] – The flight crew’s mixed fleet flying routinely exposed them to large variations in take-off weights and take-off performance parameters, which adversely influenced their ability to form an expectation of the ‘reasonableness’ of the calculated take-off performance parameters