CHARGING OF AIRCRAFT - HIGH-VELOCITY COLLISIONS

A laboratory investigation into the charge transferred to a metal target during high-speed collisions with ice crystals has shown that the charge separated at a speed of 25 m s− 1 is greater than the charge separated at higher speeds under the same cloud conditions. It is suggested that the reduction in charge transfer at high speeds is because of the reduced contact time between the interacting particles. The sign of the charging is negative in conditions of zero liquid water content at all temperatures; the charging is positive at warm temperatures in the presence of liquid water. Thus, aircraft may charge negatively at high altitudes and positively at lower levels when they encounter water droplets. © 1989 American Institute of Aeronautics and Astronautics, Inc. All rights reserved.