Ironically enough, that exact ship was flown on the search for the Era S76 on the night it went down. It was fairly well equipped, with dual radar altimeters which provided both aural and visual warnings of descent below the set DH, and digital altitude display at the bottom of the ADI. What you failed to mention was that the PIC hadn't flown in the GOM in several years, the SIC was brand new, both put in that cockpit to fill in for striking pilots, and that they were flying visually in poor weather. With only the two pilots aboard, it wouldn't have been that difficult to fly the trip IFR, but I doubt it was even considered.