In DCS World:
C:\Program Files\Eagle Dynamics\DCS World\Scripts\Aircrafts\_Common
at line 31 by add the -- red lines
purposes = {--render_purpose.GENERAL,
render_purpose.HUD_ONLY_VIEW,
render_purpose.SCREENSPACE_OUTSIDE_COCKPIT,
render_purpose.SCREENSPACE_INSIDE_COCKPIT} -- set purposes to draw it always
render_target_always = true end