Condolences to all. Used to have a lot of involvement with LUX and LG in particular, though on the handling side so do not know flight crew.
I may be in totally the wrong area, but I know on one of the approaches to LUX, if slightly too steep before capturing the glide, you often used to get a 'spurious' GPWS warning due to hills in the area, even though your turn to capture the ILS avoided these. As I said, I may be totally in the wrong area, and the comments above regarding the 'stationery' prop may point to other causes, but could CFIT be an issue?