Introductory comparison of agricultural and single-engine air tanker operational loads

Abstract

Flight loads of aircraft flown for agricultural applications have been compared with those flown as single-engine air tankers to assess the dependence of the load factors exerted on these airframes on the type of operation. Recorded flight data from two Air Tractor AT802A aircraft, two PZL-M18 airframes, and one Ayers Thrush S2R-T45 have been used for this analysis. Gust and maneuver loads spectra have been extracted for various phases of flight. It is shown that firefighting aircraft experience relatively large load factors during the drop phases once or twice a mission, while agricultural operations subject the aircraft to less severe load factors, but many more times per mission. It is also shown that the load factor alone may not be the proper indicator of the stresses exerted on the airframe.