By the end of July, Airbus’ flagship, the A380, had completed 178 hours in the sky over 52 flights and had already moved into a more detailed phase of flight testing after an initial evaluation of the aircraft’s flight behaviour and handling.
This initial evaluation of the A380 in flight was successfully concluded on 1st July after 37 flights and involved four main activities: the opening of the flight envelope, preliminary cruise performance assessment, low speed performance for aerodynamic configuration optimisation and early systems’ screening. This phase was achieved well within the anticipated timescale and provided a good indication of the maturity of the A380’s flight characteristics and flight control system.
This maturity was particularly evident by its flight demonstrations at Le Bourget Air Show as well as the successful accomplishment of the A380’s first autoland during flight 17, a mere 35 days after its maiden flight. This is the first time that an Airbus programme has undertaken this significant test at such an early stage of a flight test campaign.
Equally important was the indication that the aircraft’s cruise performance is on-target. Carried out during the preliminary performance tests three weeks after the first flight, the flight operations teams measured the A380’s specific air range, a parameter that dictates the amount of fuel in kilogrammes necessary to cover a distance of one nautical mile (1.85 kilometres) and therefore governs the overall range of the aircraft.
The flaps and slats configurations have already been frozen, to measure take-off and landing performances and continue the development of the systems depending on these configurations.
To prepare for more detailed flight tests, including the flutter campaign, the A380 returned to the flight-line hangar for the installation of certain systems’ upgrades and a six-metre mini-cabin. The latter will allow A380 maintenance staff to accompany the aircraft when it undertakes external missions (e.g. for extreme temperature testing) as well as permitting preliminary checks of cabin systems such as the emergency oxygen supply.
Less than a week after this upgrade, the A380 successfully undertook preliminary VMU (Vitesse Minimum Unstick) tests at Istres air base in Southern France after being fitted with its innovative tailbumper (see Airbus Letter, March edition) to prevent serious damage to its rear fuselage. Since then, the A380 has successfully begun flight vibration tests, known as the flutter campaign. This involves an analysis of the aircraft’s structure and aerodynamics at velocities of up to 375Kts and 0.96 Mach while also being subjected to vibrations.
The tests reproduce vibrations that can be caused by wind, turbulence or flight control movements, by intentionally introducing sharp deflections of the A380’s control surfaces (ailerons, rudders and elevators).
After completion of the flutter campaign, there will be a shift of focus to autoland development and identification flights. Identification flights help determine the parameters of the models used to represent the flight- and ground- handling behaviour of the aircraft. These flight simulation models will then be used for A380 full-flight simulators and for fine-tuning its fly-by-wire control laws.
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A380 Completes Nearly 180 Flight Hours In First Three Months Of Its Flight Test Campaign
