Arguably neither accident had anything to do with the fact that it was a rooftop operation (did I say this before?). Still the events had such a traumatic effect that not only did they factually put an end to New York City rooftop ops, but also created the urban legend that the Pan Am Helipad was closed down after the 1977 ground accident (both stated with authority here by some posters, as well as in the Bloomberg video). While we now learned that others airlines revived operations in the 1980s.