In the wake of the fall of Rabaul , the Catalinas of Nos. 11 and 20 Squadrons became the RAAF 's only offensive weapon against the Japanese . Their raids on Rabaul did little to stem the Japanese advance , and in the following months Port Moresby itself was subjected to increasingly frequent attacks , which destroyed aircraft , facilities , and squadron records . In February 1942 , the Short Empires operated by Nos. 11 and 20 Squadrons were transferred to the newly formed No. 33 ( Transport ) Squadron . No. 20 Squadron lost two Catalinas during patrols on 4 and 6 May ; the nine crewmen of the first were later found to have been captured and beheaded ; the crew of the second were also captured and subsequently disappeared without trace .