The PZL.23 Karaś was a Polish light bomber and reconnaissance aircraft, designed in the mid-1930s by PZL in Warsaw. It was the main light bomber in the Invasion of Poland.
In 1939, the plane was not a modern one. Its main fault was low speed, its manoeuvreability was not high as well. At the outbreak of the World War II, on September 1, 1939, Poland had 118 PZL.23B in combat units (further 50 PZL.23B and 35 PZL.23A were in air schools or under repairs). PZL.23B were used in 5 bomber squadrons of the Bomber Brigade and 7 Army reconnaissance squadrons, each with 10 aircraft (other squadrons of the Bomber Brigade were equipped with PZL.37 Los). They actively took part in the Invasion of Poland. Some planes were also used in a wartime improvised units.
On September 2, 1939, one PZL.23B of the 21st escadre bombed a factory in Olawa as the first bomb attack on the German territory. The bomber squadrons attacked German armoured columns, while the main mission of Army squadrons was reconnaissance. All PZL.23 suffered high losses due to low speed, lack of armour and fighter protection. Many were shot down by the German fighter planes, but they also shot down a few in return. Some 20 aircraft crashed on rough field airfields. The five squadrons of the Bomber Brigade delivered about 52-60 tons of bombs during the campaign, the Army squadrons added about a dozen tons of bombs as well. About 90% of PZL.23 were destroyed in 1939. In addition two PZL.43A from the Bulgarian order were impressed into Polish service in the 41st Squadron.
11 PZL.23B and about 20 PZL.23A were withdrawn in 1939 to Romania and then used by the Romanian air force against the USSR. 50 PZL.43 and PZL.43A (2 were delivered by the Germans) were used in Bulgaria for training until 1946, with a name "Chaika". No PZL.23's were left in Poland after the war.
