On April 30, 1967, on their 93rd mission (seven shy of completing their tours), Thorsness and Johnson were shot down by a Mikoyan-Gurevich MiG-21 over North Vietnam while flying aircraft F-105F, AF Ser. No. 62-4447. He had flown the morning mission to the Hanoi area as Wild Weasel leader, then assigned himself as a spare aircraft for the afternoon mission because of a shortage of crews. One of Carbine flight aborted with radio problems, and Thorsness filled in as Carbine 03, leading the second element.