This mod from PieJesu increases the range of the flashlight.
This mod increases the lighting distance of the flashlight to a more realistic setting. It may impact your performance due to the increased NPC and player lighting range but it provides a more realistic experience.
1. In fsgame.ltx in Clear Sky rootdirectory change the first false to true
at the parameter $game_data$, so it looks like this:
$game_data$ = true | true | $fs_root$ | gamedata
2. Put the folder "gamedata" from this mod in Clear Sky rootdirectory.
Example: C:GamesS.T.A.L.K.E.R. - Clear Skygamedata