Support from Below

TLD teamed up with Rexroth to create a machine that would take on the A380.

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Supporting the Airbus A380 — the largest commercial aircraft in the world with room for 555 passengers — from the ground will require a new fleet of equipment. One company, TLD Europe, headquartered near Paris, France, undertook the challenge of developing a towbarless aircraft tractor for the A380.

While staying true to TLD's company philosophy: innovative, simple, reliable, the world-wide specialist in airport ground support introduced the TPX 500 S towbarless aircraft tractor. The machine simplifies the coupling of the plane to the towing tractor, improving safety and efficiency.

The vehicle has a U-shaped tail and drives backward toward the nose landing gear of the Airbus, then encloses the front landing gear. Hatches lock onto the gear's framework. A blade then drives forwards and fixes the wheels to the hatches. The tow tractor then lifts the nose landing gear to move the aircraft around the tarmac. The Airbus can weigh 600 tons fully loaded.

Faster and more secure

The fully automated latching and release of the towbarless technology significantly increases safety and efficiency. Unlike when using towing bars, only one operator is required for the TPX 500 S, who as the driver has a direct line of vision to the aircraft's landing gear. The time-consuming handling process, which was prone to accidents and used heavy towbars and coupling devices, is no longer necesary.

With the "shouldering" technique, TLD has simplified and sped up the process considerably.

Once the airplane is secure, the towing tractor pushes the Airbus backwards into the take-off position (the pushback) or pulls the aircraft to areas of the airport that are further away. This innovative solution guarantees considerably smoother acceleration and breaking maneuvers, which protects the landing gear as well as the passengers.

These requirements place the highest of demands on the hydraulic system. TLD worked in close co-operation with Rexroth on the development and design of the hydraulic power unit.

The hydraulic system supplies the required power for the 600-ton giant by means of two A4VG axial piston double pumps and two A6VM axial piston variable displacement motors with a power rating of 583 kW. The traction drive control design is based on the hydro-mechanic DA traction drive control system which is sensitive but extremely robust and easy to assemble.

"The advantages of Rexroth components lay in the fact that the products were already available in series production. This means we are guaranteed established and reliable equipment with international and uncomplicated customer service," says Hervé Criquillion, CEO of TLD Europe.

Double the service life

Even with this project, TLD and Rexroth set their sights on as simple a solution as possible by reducing the number of lifting cylinders. In this way the TPX 500 S fulfils the constantly increasing demands of end users with regard to improved reliability and longer service life. The volume of air traffic is growing rapidly and the airport service industry is in the grip of this change.

"Our equipment is now used for 3,500 hours instead of 1,500 hours per year," says Criquillion. "At the same time, the product life expectancy has doubled from 10 to 20 years."

World-wide service guaranteed

During development, TLD made use of Rexroth's knowledge of mobile applications. "We are not hydraulics specialists," the CEO of TLD Europe says. "In that respect we rely on our partner company who can offer world-wide technical knowhow and service to our 250 customers in 100 countries."

In collaboration with the French Rexroth specialists, TLD performed the development in under 12 months from project start to delivery. TLD builds around 150 towing tractors per year, all of which are equipped with Rexroth components and systems. In the future, the TPX 500 aircraft tractor will also be supplied for other versions of the A 380, for example for the "Ultimate Freighter", planned for 2008.