On the night of 20 March 2009, an Airbus A340-541, registered A6-ERG and operating as Emirates EK407, with 18 crew and 257 passengers, sustained a tailstrike and overran the end of the runway on departure from Melbourne Airport, Victoria. The investigation found that the accident resulted from the use of erroneous take-off performance parameters. Those erroneous parameters were themselves a result of an incorrect take-off weight being inadvertently entered into the electronic flight bag during the pre-departure preparation. Due to a number of factors, the incorrect data entry passed through the subsequent checks without detection.
As part of its investigation of the accident, the ATSB undertook a research study titled Take-off performance calculation and entry errors: A global perspective to review the factors involved in a number of incidents and accidents in the 20 years leading to 2009. That report indicated that this accident was just one of many occurrences involving the use of erroneous take-off performance parameters across a range of aircraft types, operators, locations and types of operation.
As in the accident under investigation, a consistent aspect of these occurrences was the apparent inability of flight crew to perform 'reasonableness checks' to determine when parameters were inappropriate for the flight. Equally significant was that degraded take-off performance was generally not detected by the flight crew until well into the take-off run, if at all. The investigation found that the take-off performance philosophy used in civil transport aircraft did not require the flight crew to monitor the acceleration of the aircraft or provide a reference acceleration that must be achieved.
As a result of the accident, the operator and aircraft manufacturer have taken, or are taking, a number of safety actions. In addition, the Australian Transport Safety Bureau (ATSB) has issued a safety recommendation to the United States Federal Aviation Administration and a safety advisory notice to the International Air Transport Association and the Flight Safety Foundation in an effort to minimise the likelihood of future similar events.
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Interim Factual report released 18 December 2009
On 20 March 2009, at 2230:49 Eastern Daylight-saving Time (1130:49 UTC), an Airbus A340-541 aircraft, registered A6-ERG, commenced the take-off roll on runway 16 at Melbourne Airport, Vic. on a scheduled 14-hour passenger flight to Dubai, United Arab Emirates (UAE). Onboard the aircraft (operating as flight number EK407) were 257 passengers, 14 cabin crew and 4 flight crew.
During the reduced thrust takeoff, the aircraft's tail made contact with the runway surface, but the aircraft did not begin to climb. The captain commanded and selected take-off and go-around engine thrust and the aircraft commenced a climb. After jettisoning fuel to reduce the landing weight, the flight crew returned the aircraft to Melbourne for landing.
The investigation has determined that the pre-flight take-off performance calculations were based on an incorrect take-off weight that was inadvertently entered into the take-off performance software on a laptop computer used by the flight crew. Subsequent crosschecks did not detect the incorrect entry and its effect on performance planning.
As a result of this accident, the aircraft operator has undertaken a number of procedural, training and technical initiatives across its fleet and operations with a view to minimising the risk of a recurrence. In addition, the aircraft manufacturer has released a modified version of its performance-planning tool and is developing a software package that automatically checks the consistency of the flight data being entered into the aircraft's flight computers by flight crews.
The investigation has found a number of similar take-off performance-related incidents and accidents around the world. As a result, the Australian Transport Safety Bureau (ATSB) has initiated a safety research project to examine those events. The findings of that project will be released by the ATSB once completed. In the interim, the ATSB has drawn this interim report to the attention of relevant Australian operators to highlight the risks when calculating and checking take-off performance information.
Preliminary report released 30 April 2009.
At 2231 Eastern Daylight-saving Time, an Airbus A340-500 aircraft, registered A6-ERG, commenced the take-off roll on runway 16 at Melbourne Airport on a scheduled, passenger flight to Dubai, United Arab Emirates with 257 passengers, 14 cabin crew and four flight crew. The takeoff was planned as a reduced-power takeoff and the first officer was the handling pilot for the departure.
At 2231:53, 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 take-off weight, which was 100 tonnes below the actual take-off weight of the aircraft, had inadvertently been used when completing the take-off performance calculation. The result of that incorrect take-off weight was to produce a thrust setting and take-off 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
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 take-off performance data entry.
The existing take-off certification standards, which were based on the attainment of the take-off reference speeds, and flight crew training that was based on monitoring of and responding to those speeds, did not provide crews a means to detect degraded take-off acceleration.
|Who it affects:||Flight crews|
|Status:||Safety action pending|
The available Cross Crew Qualification and Mixed Fleet Flying guidance did not address how flight crew might form an expectation, or conduct a ‘reasonableness' check, of the speed/weight relationship for their aircraft during takeoff.
|Who it affects:||Flight crews|
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.
|Who it affects:||The operator’s flight crew|
The operator’s training and processes in place to enable flight crew to manage distractions during the pre-departure phase did not minimise the effect of distraction during safety critical tasks.
|Who it affects:||The operator’s flight crew|
The failure of the digital flight data recorder (DFDR) rack during the tail strike prevented the DFDR from recording subsequent flight parameters.
|Who it affects:||Operators of A340 aircraft|
|Date:||20 March 2009||Investigation status:||Completed|
|Time:||22:32 ESuT||Investigation level:||Complex - click for an explanation of investigation levels|
|State:||Victoria||Occurrence type:||Ground strike|
|Release date:||16 December 2011||Occurrence category:||Accident|
|Report status:||Final||Highest injury level:||None|
|Aircraft manufacturer||Airbus Industrie|
|Type of operation||Air Transport High Capacity|
|Damage to aircraft||Substantial|
|Departure point||Melbourne, Vic.|
|Departure time||2232 ESuT|
|Destination||Dubai, United Arab Emirates|