[3] Om 26 March 1943, Preinfalk claimed a Supermarine Spitfire fighter shot down 10 kilometers (6.2 miles) northeast of El Hamma.

The Gruppe under command of Hauptmann Julius Meimberg was fighting in defense of the Reich and largely staffed by inexperienced young pilots.

The authors state, that particularly Oberstleutnant Johannes Steinhoff, the commander of JG 77 at the time, had a number of pilots transferred for redemption in defense of the Reich combat, this measure included pilots Preinfalk, Major Heinrich Bär, Hauptmann Lutz-Wilhelm Burckhardt, Leutnant Ernst-Wilhelm Reinert, and Oberfeldwebel Herbert Kaiser.

[9] Preinfalk was killed in action on 12 December in aerial combat with a Republic P-47 Thunderbolt fighter 1.5 kilometers (0.93 miles) southwest of Graben-Neudorf.

Although he managed to escape of his Messerschmitt Bf 109 G-14/AS (Werknummer 165741—factory number) at low altitude, his parachute failed to fully deploy and he fell to his death.