Air raids on Semarang–Salatiga–Ambarawa

On 21 July 1947, the Dutch forces launched Operation Product, a military offensive aimed to capture economically productive areas of the Indonesian Republican-held territories in the islands of Java and Sumatra, in violation of the Linggadjati Agreement previously signed in 1946. As part of the offensive, the Royal Netherlands East Indies Army Air Force (ML-KNIL) launched Operation Pelikaan to attack Indonesian airfields and destroy aircraft belonging to the Indonesian Air Force, and so ensuring that no Indonesian aircraft would disrupt the offensive. 24 Indonesian aircraft were destroyed on 21–23 July period and ground facilities at several Indonesian airfields were disabled. Seeing the firsthand destructive results of Operation Pelikaan, several Indonesian Air Force cadets were determined to take revenge by proposing to launch air strikes against Dutch-held territory. The idea was initially rejected by the Air Force commander Air Commodore Suryadi Suryadarma and one of his deputy then Group Captain Halim Perdanakusuma, although they later reluctantly approved the proposal. == Mission ==

Halim assigned the H-Hour of the raid at 05:00 in the morning of 29 July 1947, with Semarang and Salatiga as the targets. Four surviving aircraft at Maguwo airfield in the outskirts of Yogyakarta were allocated for this mission, which were two Yokosuka K5Y1 "Willow", one Mitsubishi Ki-51 "Sonia", and one Nakajima Ki-43 "Oscar". The two K5Y1s, to be flown by Flight Cadets Sutarjo Sigit and Suharnoko Harbani with Sutarjo and Kaput respectively as rear gunners, were assigned to target Salatiga, while Semarang were assigned to the Ki-51, flown by Flight Cadets Mulyono and rear gunner Dulrachman, and escorted by Ki-43 flown by Flight Cadet Bambang Saptoaji. During the preparation on the early hours of 29 July, it was found that the machine gun synchronization system in the Ki-43 could not be repaired in time, and the raids were to go ahead with three aircraft instead. Problem also hampered Sutarjo Sigit's K5Y1, as the defensive machine gun could not be mounted on the aircraft. == Aftermath ==

As a response to the raids, the No. 120 Squadron of Dutch East Indies Army Air Force launched offensive counter air sorties against Indonesian airfields of Maguwo and Maospati. == In popular culture ==

The air raids is one of the main plot of the 1981 film Serangan Fajar. The 2021 Indonesian film Cadet 1947 was heavily inspired and dramatized retelling of the 29 July 1947 air raids and its participants. == References ==