Executive summary
On Wednesday 12 March 2003, at 1547, flight SQ286, a Boeing 747-412 registered 9V-SMT, started its take off at Auckland International Airport for a direct 9 hour flight to Singapore. On board were 369 passengers, 17 cabin crew and 3 pilots.
When the captain rotated the aeroplane for lift off the tail struck the runway and scraped for some 490 metres until the aeroplane became airborne. The tail strike occurred because the rotation speed was 33 knots less than the 163 knots required for the aeroplane weight. The rotation speed had been mistakenly calculated for an aeroplane weighing 100 tonnes less than the actual weight of 9V SMT.
A take off weight transcription error, which remained undetected, led to the miscalculation of the take off data, which in turn resulted in a low thrust setting and excessively slow take off reference speeds. The system defences did not ensure the errors were detected, and the aeroplane flight management system itself did not provide a final defence against mismatched information being programmed into it.
During the take-off the aeroplane moved close to the runway edge and the pilots did not respond correctly to a stall warning. Had the aeroplane moved off the runway or stalled a more serious accident could have occurred.
The aeroplane take off performance was degraded by the inappropriately low thrust and reference speed settings, which compromised the ability of the aeroplane to cope with an engine failure and hence compromised the safety of the aeroplane and its occupants.
Safety recommendations addressing operating procedures and training were made to the operator, and a recommendation concerning the flight management system was made to the aeroplane manufacturer.
Related Recommendations
Develop guidelines for the use of the third pilot, for the times one is carried.
Establish procedures that ensure comprehensive, independent verification of all essential take off data, such as the TOW, reference speeds and thrust setting, is accomplished at key points before engines are started.
Implement a FMS software change on all various Boeing aircraft models that ensures any entries (such as V speeds and gross weight) that are mismatched by a small percentage are either challenged or prevented.
Use this accident scenario as a topic for pilot re-currency training or LOFT in simulators to enhance pilot awareness and CRM skills. The training should introduce similar errors for pilots to discover. The training should also ensure pilots treat all warnings, such as a stick shaker, as real warnings and make sure they respond appropriately until the threat has passed.
Reaffirm to all company pilots that, when faced with delays, safety should not be compromised in an attempt to minimise any time loss.