When the Japanese invaded northern Malaya on 8 December 1941, the B-339E initially performed adequately. Against the Nakajima Ki-27 "Nate", the overloaded Brewsters could at least hold their own if given time to get to altitude, and at first achieved a respectable number of kills. However, the appearance of ever greater numbers of Japanese fighters, including markedly superior types such as the Nakajima Ki-43 "Oscar" soon overwhelmed the Buffalo pilots, both in the air and on the ground. Another significant factor was the Brewster engine's tendency to overheat in the tropical climate, which caused oil to spray over the windscreen, usually forcing an aborted mission and greatly complicating attempts to intercept and destroy enemy aircraft. In the end, more than 60 Brewster Mk I (B-339E) aircraft were shot down in combat, 40 destroyed on the ground, and approximately 20 more destroyed in accidents. Only about 20 Buffalos survived to reach India or the Dutch East Indies. The last airworthy Buffalo in Singapore flew out on 10 February, five days before the island fell.