Scaling of Lift Degradation Due to Antiicing Fluids

Abstract

In recent years, North American civil airworthiness authorities have conducted research to develop the allowance times for aircraft operations in ice-pellet precipitation. These allowance times are critical to ensure the safety and efficient operation of commercial and cargo flights. Wind-tunnel testing with uncontaminated antiicing fluids and fluids contaminated with simulated ice pellets has been carried out to better understand the flowoff characteristics and resulting aerodynamic effects. The percent lift loss was determined at an 8 deg angle of attack and used as one of the evaluation criteria in determining the allowance times. This paper describes how the lift loss was related to the loss in the maximum lift of a Boeing 737-200ADV airplane through the aerodynamic acceptance test performed for fluids qualification. A loss in the maximum lift coefficient of 5.24% on the B737-200ADV airplane (which was adopted as the threshold in the aerodynamic acceptance test) corresponds to a lift loss of 7.3% on the test model at an 8 deg angle of attack. A statistical analysis was performed to account for data scatter in the correlation and indicated that the upper limit of lift loss on the test model was 9.2%. Therefore, for cases resulting in lift loss from 7.3 to 9.2%, extra scrutiny of the visual observations is required for evaluating fluid performance with contamination and establishing appropriate allowance times.