Flight Test Assessment of Lateral Activity

During a developmental flight test of the F/A-18E/F Super Hornet, uncommanded rolling motion was experienced while conducting maneuvers at transonic speeds. Abrupt, large-amplitude lateral events, referred to as wing drop, impaired the pilot’s ability to effectively perform air-to-air tracking tasks at these flight conditions. A modified leading-edge flap schedule and the addition of porosity in the wing fold area eliminated the problem. However, finding the solution was slowed by the lack of a validated figure of merit to correlate with computational fluid dynamics, wind-tunnel, or flight-test analysis. A method has been developed to assess lateral activity using flighttest data. The lateral activity assessment involves both qualitative and quantitative evaluations. The pilot performs the qualitative evaluation, and the quantitative evaluation is based on analysis of roll rate, roll acceleration, lateral stick position, and bank angle. This technique provides a reliable approach to assessing lateral activity levels from flight test. An excellent correlation was attained between the pilots qualitative evaluation and the quantitative flight-test data assessment.