the red and white pentagon (which was supposed to signify Indonesia's national ideology of "Panca Sila", or the "Five Principles", created by Sukarno in 1945). Action against rebellions (1950–1961) Political instability meant that the Indonesian Air Force saw action against several regional rebellions in Indonesia such as PRRI, Permesta, Darul Islam-Tentara Islam Indonesia (DI/TII) and the Republic of South Maluku separatists. Several Indonesian pilots scored their first kills, including Captain Ignatius Dewanto with his North American P-51 Mustang, who in 1958 shot down a Permesta Douglas B-26 Invader over Ambon. Its pilot, Allen Pope, an American CIA agent, was captured and tried in Jakarta, thus revealing the significant involvement of the CIA's "Operation Haik" in the rebellion. The most famous Indonesian fighter pilot in this era was Rusmin Nurjadin, who became Chief of Staff of the Air Force from 1966 to 1969. Nurjadin commanded MiG-21 squadrons in 1962–65 and founded an acrobatic team in 1962 that flew the MiG-17F/PF Fresco over some cities in Indonesia. Small numbers of Indonesian Air Force pilots gained their reputation as aces in this era. Soviet influence (1962–1965) The need to prop up to what became Operation Trikora in Netherlands New Guinea and the rise of the Communist Party of Indonesia drew Indonesia closer to the Eastern Bloc. Several Soviet-built aircraft began to arrive in the early 1960s including the MiG-15UTI from Czechoslovakia, MiG-17F/PF, MiG-19S and MiG-21F-13, in addition to Ilyushin Il-28, Mil Mi-4, Mil Mi-6, Antonov An-12 and Avia 14 also from Czechoslovakia. Indonesia also received Lavochkin La-11, as well as Tupolev Tu-2 from China, intended to replace the B-25, but they never reached operational status. These aircraft served along with the remaining American aircraft such as North American B-25 Mitchell, Douglas A-26 Invader, Douglas C-47 Dakota and North American P-51 Mustang. It was during this period that the Indonesian Air Force became the first Air Force in Southeast Asia which acquired the capability of strategic bombing by acquiring the new Tupolev Tu-16 in 1961, before the acquisition of Ilyushin Il-28 by Vietnam People's Air Force. Around 25 Tu-16KS were delivered complete with AS-1 air-surface missiles. One crashed at the end of 1962. To add with all these purchases was the first ever surface to air air defense missile operated by Southeast Asians, the S-75 Dvina, which were acquired in 1961. This era also marked the last confrontation with the Dutch in Papua, before