Originally Posted by
ampan
One encountered bad weather and took the alternate route.
Was that before or after they switched to INS rather than ground-based navigation? It's an important distinction to make because the flights were planned, briefed and handled very differently in the first (pre-INS) year compared to the second.
I don't believe every other flight had "gin clear" conditions either - CAVOK possibly, but you can still have CAVOK with significant cloud cover.