Emirates changes procedures after Melbourne A340-500 near-loss
By Kieran Daly
Emirates has begun using a second cockpit laptop computer to cross-check crews' take-off calculations following the near-catastrophe to an Airbus A340-500 at Melbourne in March.
The move was revealed by the lead Australian investigator in a briefing to release the preliminary report on the incident, in which the aircraft overrun the runway end before lifting off following a crew error in inputting the take-off weight.
Australian Transport Safety Bureau director of aviation safety investigations Julian Walsh says: "Emirates has advised the ATSB that although there are a number of layers that are required to provide physical cross-checks during these calculations, in the interests of prudence, and until the circumstances are better understood, they have introduced a further level of independent cross-checking through the use of a second laptop computer."
The pilots in the incident, who each had more than 8,000h total time, controversially "resigned" immediately after the incident, which ended without further problems, but Walsh says: "What we need to understand, and is the difficult part, is how the system allowed that to happen. And this is going to be quite a complex thing, to look at the operating environment and what was going on in the cockpit at the time. What sort of environmental issues there were with noise and distractions - that's where the hard work is."
The ATSB details how the crew entered via the electronic flight bag a take-off weight that was 100t below the correct figure of around 362t. As a result the selected thrust-setting and take-off reference speeds were too low. The first officer flying the aircraft unsuccessfully tried to rotate in accordance with the calculations and, when the aircraft did not respond, the captain applied take-off/go-around (TOGA) power to lift off in the grass area beyond the runway, striking a light and antenna. Investigators identified three tailstrikes on the runway and two more contacts during the overrun.
Walsh says the ATSB at this stage does not think pilot fatigue was a factor, and he defended the use of reduced-power take-offs, which are widely used in the industry to save long-term engine-wear.
The ATSB says the investigation, providing one of the first in-depth examinations of electronic flight bag use, is expected to continue for several months and will examine:
- Human performance and organisational risk controls, including data entry - a review of similar accidents and incidents, organisational risk controls, systems and processes relating to performance calculations.
- Computer-based flight performance planning, including the effectiveness of the human interface of computer based planning tools.
- Reduced power take-offs, including the risks associated with reduced power take-offs and how they are managed, crew ability to reconcile aircraft performance with required take-off performance, the associated decision making of the flightcrew, and preventative methods, especially technological advancements.
