In PALAST active and passive load alleviation techniques were reviewed together. The passive measures required modification of the primary structure and thus influenced the dynamic response of the wing. An active load alleviation scheme for an aircraft was based on its static and dynamic structural behaviour. Therefore, a significant interaction of passive and active load alleviation technique was expected. Identification, analysis and optimisation of these effects were performed by a coupled flight-dynamic and aeroelastic simulation model with both load alleviation techniques implemented.

A baseline structural model was parameterised over multiple structural parameters, considering the composite layup of wing panels and stringers, which was normally employed for wingbox structural optimisation. This enabled a variable stiffness layout which may frequently be adapted in the analysis procedure. Finally, a structural optimisation task was performed, exploiting maximum efficiency of active and passive load alleviation.

PALAST enabled and developed technology for a multidisciplinary design approach, using combined active and passive load control. Taking into account all advantages of load alleviation, as well as possible detrimental interactions, a reasonable structural design with minimised weight can be achieved. Lightweight structural design takes a key role in reduction of fuel consumption and related CO2 emission, one of the “ACARE Vision 2020” goals.