Avia B-534-IV Bulgarian users

In the summer of 1939 the Bulgarian Air Force bought 78 B-534 from Germany. These were initially assigned to the 2. Istrebitelen Orlyak (2nd Fighter Air Regiment) and to the training squadron.

The last batch of this airplanes to arrive to Bulgaria was in March 1942 when 6. Istrebitelen Orlyak received some B-534-IV.
On 1st August 1943 they took part on the biggest operation this airplane would take part on when seven of them made two passes at American Consolidated B-24 Liberator bombers which were coming back from bombing Ploesti, in Romania. Even if they hit some B-24, not a single one of them were shot down due to the small calibre of their machine guns.
Some of the B-534-IV were damaged and crecked up on landing.
After Bulgaria switched sides on 9th September 1944, the B-534-IV were oftenly used in the ground attack role against German units and it's known that some B-534-IV were involved in a brief melee with six German Bf-109 at low altittude. One B-534-IV was lost and the Germans quickly broke off from combat aware of the high maneouvrability of the B-534-IV at low altittudes.

Sources:
1. https://en.wikipedia.org/wiki/Avia_B-534
2. http://surfcity.kund.dalnet.se/avia_bulgaria.htm
3. Salamander Books - The Complete Book of Fighters