On board for these tests is what is known as the Water Ballast Transfer System, with which up to 4,000 litres of water can be transferred between ten tanks.

FERCHAU's AVIATION specialists in the technical office in Bremen have developed the system from FEM analysis through the design phase using CATIA V5 to coordination with the production department.

So how does the new A400M military cargo aircraft behave in flight under various load conditions? The answer to this question is provided by the Water Ballast Transfer System (WBTS), which is installed in the aircraft during flight tests. At the heart of the system are ten aluminium water tanks each with a capacity of up to 4,000 litres, which corresponds exactly to the maximum permissible load of a cargo pallet. Secured in pallet holders at the front and rear of the A400M's cargo hold, the tanks of the WBTS are filled to different levels in order to simulate different centres of gravity.

The assignment given to the design specialists at the technical office in Bremen was clearly defined: to base the design of the WBTS on the existing A380 system. However, it soon became apparent that it would take more than just a few modifications to achieve this: the base area for pallets in the A400M is smaller than in the A380, so FERCHAU's team had to make the tank for the A400M taller to arrive at the specified volume, and differing load parameters demanded a re-design of the pallet holders in the floor of the aircraft.

Reliable base data for the design work in CATIA V5 was supplied by the FEM analysis. In addition to linear stress analysis, the work involved analysing deformation and stress conditions as well as examining the effects on the load caused by the acceleration that occurs during an emergency landing. After several calculation loops, a version was finally found that satisfied the requirements of both the customer, Airbus, and the production department. Ongoing coordination with all the other partners involved ensured that the project ran smoothly.