Guten Tag,
Peter Supf mentioned Rubin Wecsler "bei einem Probeflug am 17.07.15 in Valenciennes tödlich abgestürzt" in his book "Lexikon der Luftfahrt Bd. 2". He also describe an accident caused by Wecsler in Johannisthal 14.05.1912. Hauptmann Jucker, Chefpilot of LVG and a pupil lost lives, after their Aircraft rammed Weclers Harlan.