TURBOPROP AIRCRAFT PERFORMANCE RESPONSE TO VARIOUS ENVIRONMENTAL-CONDITIONS

This study evaluated aircraft performance response to various environm ental conditions encountered during night. These conditions included c lear air, ice only, mixed phase, and supercooled drops, Supercooled dr ops consisting of cloud, drizzle, and rain sizes were the main focus o f this study, Aircraft response was quantified by rates of change in a ircraft climb capability, drag coefficient, and lift ol er drag ratio, The aircraft performance parameters were compared to an environmental hydrometeor parameter quantifying the environmental conditions, Resul ts show that encounters with supercooled drizzle drops (SCDD) resulted in maximum rates of performance degradation, Encounters with supercoo led cloud and rain-sized drops resulted in minor to low rates of perfo rmance degradation, whereas encounters with supercooled drops in low i ce particle concentrations resulted in only minor rates of degradation , In addition, aircraft response to high ice particle concentrations, in low liquid water, following an SCDD encounter, resulted in rapid pe rformance recovery, The results presented herein show a strong relatio nship between aircraft response and an environmental parameter utilizi ng a weighted volume diameter and liquid water content, The results su ggest that the most severe icing is actually caused by SCDD as opposed to freezing rain.