 Kroll considered the Pfalz to be the Albatros's inferior in performance; He thought the Pfalz the slower of the two planes, climbed no better, but could be faster in a dive.Whichever aircraft he used, he rounded off 1917 by scoring his 15th victory on 4 December.On 25 January 1918, after he shot down a Bristol F.2b Fighter for number 17, the rear spar of the Pfalz he was flying broke, and the left aileron tore badly, almost separating from the plane.