For DLR’s own aircraft fleet, additional flight certification was necessary when structural changes were made to the aircraft within the scope of the research activities. The Institute of Aeroelasticity carries out flutter tests to determine the static and dynamic aeroelastic stability to obtain certification from the Federal Aviation Office (Luftfahrt Bundesamt - LBA). These approval tasks are generally carried out on behalf of and in close cooperation withDLR’s Development Centre (Entwicklungsbetrieb - EB). The validation of the flutter stability of an aircraft design is requested by the internationally applicable design regulations in order to obtain a type certificate. Depending on the category, the regulations CS25, CS23 and CS22 are to be observed, in which paragraphs 629 and 251 specify the contents and scope of the verification process to determine the aeroelastic stability and vibrations. Both the aircraft Antares H2, used for fuel cell research, and the Gulfstream G550 HALO aircraft, used for atmospheric research, are examples of the verification of flutter safety and the required aircraft certification.