FWIW, as a layperson, I would read "light" as "not heavy" - in the sense of the plane not being heavily loaded with weight AND/OR carrying only a minimal crew
I afraid the other interpretation, a light, non-challenging mission, seems possible to me too, though.
Is there something in the context to tell you what was making the situation grow more dangerous? Might there be a clue there? My understanding, for instance, is that heavier planes actually do better in bad weather... that would argue against the first interpretation, right?
Edit, oops, too slow again, hadn't seen #6. Also hadn't realized that it was always one and the same landing area. That does seem to argue against challenging, as Harald (dede) pointed out.