Clean Sky project wins Innovation Award

07/11/2011

TaxiBot, Clean Sky "Dispatch Towing Vehicle (DTV)" project won the Innovation Award at Inter Airport Europe in Munich.

The DTV is a towbarless aircraft tractor dedicated to dispatch towing of single aisle aircrafts (e.g. A320, B737), allowing the aircraft to stop the engines during taxiing in and out.

Even though the idea of dispatch towing exists for decades, past attempts using existing tractors - dedicated to push back and maintenance towing - faced several problems:

  • Insufficient installed power to achieve acceptable taxiing speeds for a transparent integration on taxiways, and taxiway traffic jams avoidance.
  • Excessive loads on nose landing gear (NLG) when accelerating and braking (aircraft at maximum take-off weight, average max taxiing speed 20 knots), creating fatigue and reducing life time of the NLG.
  • Responsibility: as taxiing out and taxiing in are considered as flight phases, pilot has to be responsible of the taxiing operation, and must be in control of the convoy at all time.

The DTV concept provides a comprehensive answer to the main drawbacks of classical dispatch towing, protecting airplane landing gears from excessive allowed fatigue limits at all times and allowing the pilot to stay "in control". The basic rules governing the DTV design are:

  • The DTV has sufficient power to achieve taxiing speeds compatible with a transparent integration into taxiing traffic.
  • Taxiing with DTV will be by pilot commands: steering behaviour will be "transparent to the Pilot"
  • Loads induced to NLG do not reduce its life time (fatigue considerations)
  • As a design goal, there will be no (or minor) change, alteration or modification in the towed airplane
  • Braking and speed adjustment are performed by the pilot, applying the brakes, as today, on the main landing gear

Technical details of the solution

By measuring in real time the load on the nose landing gear thanks to a unique clamping device, and by adapting its tractive effort in accordance, the DTV does not impact the structure life of the aircraft nose landing gear.

It also offers full operational transparency for the aircraft pilot, as the braking is performed by the aircraft main landing gear, on pilot demand. The clamping device allows the rotation of the nose landing gear, so the steering could be performed by the pilot using his tiller such as today. In case of aircraft limitation on steering capability with no engine running, the DTV has a "Steer-By-Wire" mode using tiller signal. The DTV will integrate embedded systems exclusively developed for this application and certified through STC certification (aerospace requirements), which will communicate with the airport environment. These systems include several control, command and communication features to allow the DTV to receive environment data (slope, wing, aircraft data) in order to adapt its tractive effort and target speed depending on its position on the air field. No modification of the aircraft is needed, communication from DTV driver to pilot is done via Intercom as today, and pilot could have additional DTV information and target speed control via electronic flight bag.

Minor changes on airport are needed, such as return roads. The DTV will be able to perform standard pushback and maintenance towing operations, as existing aircraft tractors, but with a more accurate load monitoring system, in order to limit induced fatigue loads. 

Conclusion

"The DTV project will deliver one amongst many innovative technologies developed within the Management of Trajectory part of Clean Sky, led by Thales Avionics. The semi-autonomous towbarless towing vehicle will allow a direct reduction of CO2 emissions on the airport surface by avoiding the use of engines for the taxi phase. With the involvement of Airbus in the supervision of the project, specification of the aircraft interfaces, as well as TLD Europe's role in developing the prototype, the project has the perfect partnership to deliver a solution with a high maturity level in 2012" concluded Gilles Poussin, Project Manager Clean Sky at Thales Avionics.


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