Certification and Performance Determination of a Research Aircraft with External Installations

Kurzfassung

This paper presents a quick and economical method to determine the performance penalties of additional external installations of a transport category research aircraft for certification and mission planning. DLR’s (German Aerospace Center) new HALO (High Altitude Long Range) aircraft is used for meteorological and geophysical research. The basic aircraft, a Gulfstream G550, is equipped with provisions for multiple variable external installations, which degrade the take-off, climb and cruise performance of the aircraft. Typically each scientific campaign requires a unique combination of internal and external installations. Every external installation and all combinations thereof are tested in flight. Abbreviated flight test procedures are used to spot check all installations against the requirements of the certification specification part 25. DLR uses level accelerations and decelerations as primary method to determine the performance decrease. This flight test technique is an economical and conservative way to determine the additional drag of the external installations to obtain the certification for the external installations and to estimate the range penalty in order to plan and execute the scientific mission, thus create value after a minimized flight testing effort.