Airbus Military reports on A400M progress

Airbus Military has issued a report on its progress in assembly of the first A400M military cargo aircraft.

Airbus Military (Blagnac cedex, France) in its December newsletter reports steady progress in assembly of the first A400M aircraft (designated MSN001) in Seville, France. In October, the fuselage barrel was joined to the nose fuselage section and equipped with the sponsons and landing gear.

The wing sections were assembled and the four engine pylons installed. In November, the complete 42m-long wing structure was successfully integrated with the fuselage and in early December the fully assembled empennage, (comprising the vertical and horizontal tail plane), and the main landing gear doors were put in place.

In parallel, a development engine was delivered to Marshall Aerospace in the third week of November and installed on a modified C-130 airframe. Engine trials with the flying test bed will begin during the first quarter of 2008.

The structural components of the first production wing were fully assembled in Seville by the end of July and the electrical, hydraulic, pneumatic and fuel systems installations were then completed and tested at the FAL. With the four engine pylons installed, the 42m-long wing has moved to "Station 40,"where the complete wing has been joined to the A400M's fuselage. This delicate maneuver consists of accurately aligning the wing with the center section of the fuselage.

The A400M production line includes a specially designed vacuum lifting system that raises the entire wing to suspend it above the fuselage prior to lowering it into position. Then it is fixed to the 12 attachment points by means of lugs and pins. The whole process takes approximately five days to complete. While still at Station 40, the complete empennage, consisting of the assembled horizontal and vertical tail surfaces, is integrated with the rear fuselage and the landing gear doors are installed. Now structurally complete, work continues on the aircraft's systems with power on by early 2008.

Between completion of the airframe structure and engine installation, the wing must first be equipped with the engine pylons that will carry the four TP-400 D6 turbo-props to power the A400M. The 5m-long pylons, weighing 500 kg each, consist of a titanium primary structure with a carbon composite secondary structure in the "cold"areas. Manufactured by the Airbus specialist facility at St. Eloi, Toulouse, the pylons were delivered first to the EADS facility in Tablada, Spain, for equipping and then shipped to the FAL in September 2007.

The constraints of turboprop engines imply stringent pylon architecture and design; the TP-400s, weighing 2500 kg and delivering 11,000 hp through their 5.8m propellers, provide a very special challenge. The wing-to-pylon fittings consist of two forward, one aft and a middle fitting. These are equipped with a fail-safe system doubling each of the pylon-to-wing fasteners in order to withstand the loads.

The engine attachments, four at the front and two at the back, incorporate the Engine Vibration Insulation System (EVIS), which incorporates elastomeric material designed to absorb the enormous torque and the engine and propeller vibrations generated by the powerful turboprops. As a comparison, the TP-400 engines develop six times more torque than the turbo props on an ATR commercial aircraft.

Integrated with the fuselage in early December, the complete empennage, consisting of the vertical and the horizontal tail plane (VTP and HTP), was pre-assembled before being mated with the fuselage structure.

The A400M empennage has a T-tail configuration, with the 67m2 horizontal tail plane mounted on and supported by the 11m-high fin. This arrangement not only improves the aerodynamic efficiency of the tail plane, but also reduces the risk of foreign object damage as well as providing for unobstructed access to the cargo compartment via the rear-loading ramp.

The fin structure consists primarily of composite materials, except for the removable leading edge, which is made of mixed metal and composite material for improved impact protection. Like the wing, the tail plane is mainly carbon fiber composite structure, the two outboard main planes being joined together at the centerline using titanium alloy plates.