<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by kb0fhp:
I suspect that this is the case. There is a large ridge immediately prior to the airport. Perhaps that this is what set it off.... as I said, I would be interested in seeing the approach plate.</font>
It depends on whether the approach is from the west (the usual one used) or from the east (requires much higher minimums). The ILS 10 approach comes in from the west over the ocean at Pacific Grove and there is no ridge anywhere along the approach. The approach to runway 28 from the east does have a ridge south of and parallel to the final approach course. You have to cross this ridge coming from the south (Big Sur), but this approach is usually only used in good weather conditions.
This event is also surprising, since approach control monitors all approaches and gets a warning if an aircraft drops below the glide slope.