There was an accident years ago on a night approach to one of Hawaiian airports, crew of a business jet lost sight of PAPI but interpreted this that a small cloud got between them and the PAPI, in fact they were wrong, there was no cloud, they were too low. Everyone perished.
olasek, it's been unusually rainy around Birmingham this summer, and 5 in the morning is prime time for fog. Your example may very well have happened in this crash. The pilots thinking the lights were obscured by a low lying cloud or bank of fog, not realizing it was a hill. There's also a chance of light refracting over the crest of the hill, as sometimes happens in moist conditions, making it seem like they had straight line of sight to the runway, when actually, the light was "bent" over the crest of the hill by refraction.