I found this webpage:
http://xn--fliegerhorst-strmede-ibc.de/40383.html
and also this one:
https://web.archive.org/web/20170125...lter.de/?p=615
Going into more details about the burial of Weibl (there is a picture, not the same as above, but the same man). Apparently he was supposed to fly a test flight in the area BURG, BRANDENBURG, MAGDEBURG, HALBERSTADT, STENDAL, HALLE. Half of these places are NE of Magdebug but not all. The family believed for years that he crashed in the Harz moutains (SW of Magdeburg) until in 1967 the grave of an "unbekannt Turbojäger" was opened in Geseke and the ID disc of Weibl was found in it. So the loss location was wrong, and the guy buried in Geseke is the right Weibl.
As for his first name, the first link above is using August, and is supposed to come in part from his son, so I guess it should be taken into account. Still half of the sources use Gustav and the other August, so maybe one first name was the official one and the other the one he used in daily life.
Thanks to those who replied. By the way, René, what is the FPN you used on the Deutsches Rotes Kreuz website ?