The standard Polish light bomber and reconnaissance aircraft, the PZL.23 Karaś could not be exported because of licence restrictions on the use of the Polish-built (PZL) Bristol Pegasus engine.

The PZL was more successful in Bulgaria, then reforming their airforce after a period of post-World War I treaty constraints.

The differences between the two types derived chiefly from use of the heavier and longer (two rows of seven cylinders) Gnome-Rhône engine.

To maintain the centre of gravity the fuselage was lengthened by adding one central section which moved the bombardier's gondola rearwards.

In March 1938, Bulgaria ordered a further 42 aircraft powered by the new Gnome-Rhône 14N-01 engine, an improved 14K design that delivered 950 to 1,020 hp (708 to 761 kW).

After the German invasion of Czechoslovakia in March 1939, in an increasingly tense political situation, the Polish Air Force proposed to requisition from the Bulgarian order of PZL.43As.

At the time of the German invasion of Poland, nine[2] PLZ.43As of the Bulgarian order were crated ready for delivery or were incomplete, two lacking propellers.

Five were moved to the airfield at Bielany and taken over by the Polish Air Force for use by 41 Eskadra Rozpoznawcza (41st Reconnaissance Squadron)[2] which was mostly equipped with PZL.23 Karaś.

Another three complete aircraft from the Bulgarian order were left at Okęcie and these were damaged during an air raid on 4 September and later captured by the Germans in a factory in Warszawa-Okęcie.

Data from Polish Aircraft 1893–1939[4]General characteristics Performance Armament Avionics RH-32 bomb-sight