[1] Kaldrack is credited with at least 24 aerial victories, 3 of which claimed during the Spanish Civil War flying with Aufklärungsgruppe 88 of the Condor Legion.

[2] Kaldrack was born on 25 June 1913 in Stargard, at the time in the Province of Pomerania of the German Empire, present-day in northwestern Poland.

Kaldrack volunteered for military service in the Kriegsmarine of Nazi Germany in 1934 and transferred to the Luftwaffe a year later.

[7] After he returned from Spain, Kaldrack served on the staff of Generaloberst Erhard Milch in the Reichsluftfahrtministerium (RLM—Ministry of Aviation).

[4] In early 1939, Kaldrack, together with Wilhelm Balthasar and Anhäuser, flew a Siebel Fh 104 Hallore twin-engined transport aircraft on one of the longest flights to Africa, covering 40,000 kilometers (25,000 miles).

[4][10] World War II in Europe began on Friday 1 September 1939 when German forces invaded Poland.

[13] During the aerial battle, his Messerschmitt Bf 109 E-1 (Werknummer 3397—factory number) sustained combat damage, resulting in a forced landing at Westerland on the island of Sylt.

During the landing attempt at Trier-Euren Airfield, the aircraft overturned injuring Kaldrack and his radio operator Feldwebel Eich Hermanski.

Gruppe of ZG 76 supported Junkers Ju 87 dive bombers in their attack on enemy shipping.

[16] In preparation of Operation Barbarossa, the German invasion of the Soviet Union in June 1941, SKG 210 was ordered to airfields close to the German-Soviet demarcation line.

[24] Attacking a Soviet airfield at Kozova on 30 June, Kaldrack claimed a Polikarpov I-16 fighter aircraft shot down.

[25] Kaldrack and his aerial gunner Unteroffizier Martin Enke were killed in action on 3 February 1942 south of Toropets during the Toropets–Kholm offensive.

[26][27] According to Heaton, Lewis, Olds and Schulze, Kaldrack was credited with 24 aerial victories, including three during the Spanish Civil War.