Singapore Airlines flight SQ286 taxied to runway 23L at Auckland’s International Airport and was cleared for takeoff. When the captain rotated the airplane for lift-off the tail struck the runway and scraped for some 490 metres until the airplane became airborne. The tail strike occurred because the rotation speed was 33 knots less than the 163 knots required for the airplane weight. The rotation speed had been mistakenly calculated for an airplane weighing 100 tonnes less than the actual weight of 9V-SMT. A takeoff weight transcription error, which remained undetected, led to the miscalculation of the takeoff data, which in turn resulted in a low thrust setting and excessively slow takeoff reference speeds. The system defences did not ensure the errors were detected, and the airplane flight management system itself did not provide a final defence against mismatched information being programmed into it. During the takeoff the airplane moved close to the runway edge and the pilots did not respond correctly to a stall warning. The final report did not contain a “Probable cause”.