20 March 2009

Conditions and Environment

YMML ATIS U 1050Z 25004KT CAVOK 17°C Q1015N

• Night, no moonlight, otherwise good conditions.
• No aircraft deficiencies.
• Experienced and fully qualified crew (fully enlarged).
• Take-off on runway 16, 3657×60 meters.

Incident/Accident

• Take-off mass in performance calculation was 100 tons less than actual (264 tons instead of 364 tons, as intended).
• This resulted in incorrect take-off speeds, thrust and flap settings (Vr of 145 knots and Flex 74° for Flaps 1+F instead of Vr 161 knots and Flex 43° with Flaps 3).
• At the calculated Vr and with configuration 1+F, the aircraft was unable to become airborne.
• The CM1 applied maximum thrust.
• The aircraft continued the take-off run on soft ground past the end of the runway and became airborne with a tailstrike.

Outcome

• Damage to localizer antenna and approach lights.
• Tailstrike, unable to pressurize aircraft, overweight relanding after partial fuel jettison.
• Fatigue not considered a contributing factor.
• Crew qualified on different Airbus variants (A340-200/-300/-500) with a wide range of operating weights considered a possible contributing factor.
• Event is likely to have ended catastrophically if the aircraft would have been judged “unable to fly” and an RTO conducted.
• The official report by the Australian TSB lists 12 similar incidents and accidents between 1991 and 2008.