Flight loads spectra of two business jets

Abstract

Operational flight loads have been analyzed from two business jets, a Global 5000 and a Global Express XRS. It is shown that due to the differing nature of their missions, both airframes were subjected to nearly the same number of ground-air-ground cycles, even though the flight times were much different. Flights have been divided into various phases, and loads and turbulence data have been categorized by altitude bands within each phase. Cumulative occurrences of incremental vertical gust load factors have been compared and shown to be comparable for the two airframes. Maneuver load factors have been shown to spread over a wider range of values for the 5000 in every phase. This has been confirmed through comparison of combined loads with those from a CRJ100 and an ERJ-145XR. Some derived and continuous gust velocities, obtained from the load factors are presented, along with generalized exceedance curves and their comparison with FAA-ADS-53 at various altitudes. These results from both aircraft are shown to agree well, but show significantly lower frequencies of exceedance than expected. It is suggested that the gust alleviation factor used in these calculations should be reexamined for modern more flexible aircraft using a much larger volume of data.