The new generation of high performance fighter aircraft rely upon digital controls, which improve their handling and manoeuvering capabilities, and allow unstable aeroplanes to fly. The development of these advanced digital flight control systems for a modern military aircraft is strongly influenced by aeroservoelastic effects (ASE), which, therefore, play a very important role in the qualification of aircraft with digital controls. The recognition of ASE as a serious design issue evolved as a result of advancements within independent technical disciplines, all aimed at improving the performance of flight vehicles. For example in the technical disciplines of structures and materials, structural efficiency and weight minimization resulted in very flexible structures which satisfied aeroelastic and strength requirements. There were also advancements in fly-by-wire and digital flight control system technologies that further increased their performance and capability. As a result of these advancements, large magnitude adverse aeroservoelastic responses and instabilities had the potential to, and at times did, couple to produce the phenomenon known as flutter. Flight flutter testing should be viewed as involving an inherent element of danger. The flight test procedures must be first and foremost concerned with flight safety. During the initial stages of flight flutter testing a new type of aircraft, the flight envelope is opened progressively in terms of Mach number and airspeed. Most of the tests could be improved. The conclusions of the AGARD Specialists' Meeting on 'Aeroservoelastic Testing and Data Analysis' are that most of the tests need improvements, some tests should be better exploited and at least one test - the in-flight measurement of unsteady airloads - should become standard practice to close a gap in the logic of flutter certification.

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