Airbus readies new tools to prevent runway excursions

Washington DC
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Airbus plans to certificate early in 2009 a suite of new safety and efficiency tools designed to help pilots avoid runway excursions as well as increase airport capacity and save brake life.

Available initially on the A380, the optional software upgrade includes Airbus's brake-to-vacate (BTV) system that allows pilots to preset their desired turn-off point on a runway. The system automatically commands the aircraft's auto-braking system to stop in the required distance with a deceleration profile that saves brake life.

Originally developed as a means of reducing runway occupancy time - hence its exposure to a runway incursion - the system has evolved into a more comprehensive tool to prevent runway excursions (aircraft veering off the runway during landing roll or exit).

Speaking at the US Federal Aviation Administration's 5th international aviation safety forum in Washington DC in early December, Airbus experimental test pilot Etienne Tarnowski said Airbus will initially certificate the suite on the A380, and offer the upgrades for the A320, A330 and A340 families.

The BTV system shows pilots two lines on the electronic airport diagram on the A380's navigation display. The first line shows the minimum stopping distance for dry pavement (assuming no reverse thrust). The second line shows the minimum stopping distance for a wet runway. Pilots can then select their desired turn-off point on the display using a cursor, and the system internally computes the required auto-braking deceleration profile. Contaminated runway scenarios will be addressed in later versions of the programme, says Tarnowski.

In addition, the system will issue a caution message on the primary flight display if the runway is too short because of an unstable approach or if weather conditions have changed.

Once the aircraft has landed, the system will also warn pilots visually and audibly if the continually updated stopping point moves past the end of the runway. When that happens, the auto-braking system is then commanded to apply the maximum rejected take-off braking regardless of runway conditions.

Tarnowski says that programme inputs for the A320 and A330/A340 families are likely to have to be entered numerically into the flight management system as those aircraft do not have integrated navigation displays with airport diagrams offered on the A380.