On this date,
Bernard Henri Barny de Romanet claimed a Rumpler shot down in flames in the area of Villers-Cotterets. CGAS shows a crew of FA 264(A)s lost at Vierzy which is near Villers Cotterets. Barny de Romanet claimed his victory went down in flames which would argue they were killed. I know that SPA15 claimed a DFW CV in the same area on the same date.
NB FA264(A) recorded casualties at Villers-Cotterets on 31 May 1918.
Is this a possible match?