Qantas Airways has upgraded warning systems on its Airbus A380s after an incident last year where the take-off speeds were not displayed on an aircraft's flight instruments, as a result of a failure by the flight crew to follow proper procedures.
The incident involved the crew of an Airbus A380-800, registration VH-OQE, on 8 October 2011. The aircraft, bound for Melbourne Airport, was preparing to take off from Los Angeles International Airport.
Prior to departure, the crew, consisting of the captain, a first officer and two second officers, decided to take off from the longer runway 25L instead of the planned runway 24L because of strong tailwinds.
The Australian Transport Safety Bureau (ATSB) found that when the captain was about to amend the runway number on the flight management system, they were alerted to a problem with a passenger cabin door. This caused him to forget the initial runway change he needed to make on the system.
He subsequently made the adjustment at a much later time. The error was only detected when the aircraft was near the runway as the flight crew was focused on the taxi to the runway.
The crew then noticed the lack of flight mode annunciations during the aircraft's acceleration on the runway. These included the manual take-off thrust and speed reference, which should have been shown on the primary flight displays.
When the aircraft reached 100kt (185 km/h), the captain realised they did not have the take-off speeds displayed on the flight displays. The crew decided to call out speeds from their notes instead and proceeded with the take-off.
The flight continued to Melbourne without incident.
The ATSB found that although the captain had changed the departure runway in the aircraft's flight management system, the procedure for completing the task was not followed exactly. This led to the take-off speeds not being displayed on the flight instruments.
It added that twice before take-off, the aircraft systems had displayed a message to check take-off information. The first officer cleared the first message on the understanding that the data would be checked, and again on the second instance, "believing that it had been checked".
"There were no other warnings in place to alert the crew that they were commencing take-off without the take-off speeds in the aircraft's navigation systems," says ATSB.
ATSB added that the subsequent complexity of the taxi, and repeated need to change the take-off performance calculations further increased the crew's workload.
In response to the incident, Qantas has worked with the aircraft manufacturer to introduce a new electronic centralised aircraft monitor on its fleet of A380s. A warning will be triggered by the monitor if take-off commences without take-off speeds being entered into the systems.
The flight crew operating manuals have also been amended to avoid misinterpretation of required actions in the event of a runway change.