Examination of Derived Gust Velocities from a Fleet of Aerial Supervision Module/Lead Aircraft

Abstract

Flight data collected from a fleet of Beechcraft King Air airframes have been analyzed. The data consisted of information from 3094 flights in various missions flown for the U.S. Forest Service. The missions consisted of those in support of aerial firefighting as well as passenger and ferry operations. The 2 s rule for separation of gust and maneuver load factors has been examined and deemed adequate. Gust and maneuver loads spectra for ground–air–ground are shown to correlate better with altitude above ground than with altitude relative to mean sea level. The flights are separated into six specific phases, some of which are unique for firefighting missions. The incremental vertical gust loads are then used to find derived gust velocities for each flight phase and for the entire flight. The derived gust velocity spectra are shown to be independent of the flight phase and depend only on altitude. It is concluded that the development of such spectra for individual flight phases is unnecessary and that a single spectrum, showing altitude dependence, is equally applicable to all phases of flight.