It seems there is some article by Daniel Orme and Thomas Hyatt ( 2 neuropsychologists) is going to be published in "Human Factors and Aerospace Safety" that claims it was the Barons head wound (from a .303 round fired by a 2 seater) that he sustained in July 1917 that was responsible for his "target fixation" that got him killed in April 1918.
I find this rather questionable, since he shot down another 22 a/c after this head wound occured (more kills than 90 percent of all WW1 aces), not to mention he led JG1 on top of that, doing admin work as well...
Victory's post "wound":
58 Aug. 16, 1917 Nieuport 17 Houthulster Wald
59 Aug. 26, 1917 Spad VII Poelcapelle
60 Sept. 2, 1917 RE 8 Zonebeke
61 Sept. 3, 1917 Sopwith Pup Bousbecque
62 Nov. 23, 1917 DH 5 Bourlon Wood
63 Nov. 30, 1917 SE 5a Moevres
64 Mar. 12, 1918 Bristol Fighter F 2b Nauroy
65 Mar. 13, 1918 Sopwith Camel Gonnelieu
66 Mar. 18, 1918 Sopwith Camel Andigny
67 Mar. 24, 1918 SE 5a Combles
68 Mar. 25, 1918 Sopwith Camel Contalmaison
69 Mar. 26, 1918 Sopwith Camel Contalmaison
70 Mar. 26, 1918 RE 8 Albert
71 Mar. 27, 1918 Sopwith Camel Aveluy
72 Mar. 27, 1918 Bristol Fighter F 2b Foucacourt
73 Mar. 27, 1918 Bristol Fighter F 2b Chuignolles
74 Mar. 28, 1918 Armstrong Whitworth FK 8 Mericourt
75 April 2, 1918 FE 8 Moreuil
76 April 6, 1918 Sopwith Camel Villers-Bretonneux
77 April 7, 1918 SE 5a Hangard
78 April 7, 1918 Spad VII Villers-Bretonneux
79 April 20, 1918 Sopwith Camel Bois-de-Hamel
80 April 20, 1918 Sopwith Camel Villers-Bretonneux
He wasnt the only ace to get fixated on an enemy fighter in WW1, he made a tactical mistake yes, but there seems to be little evidence that the head wound was a decisive factor in his final combat. He was tired to be sure, and his wound did give him trouble, but thats a far cry from calling him unfit to fly in combat. That being said, in WW2 and after, he probably would have been grounded after sustaining a wound like he did, in most air forces.
Anyways, interesting stuff.