say they flew for two hours to Ascension, dumped fuel, and then prepared to land. Whist circling around, say our good friends from the RAF land and have a serious malfunction that closes the runway. Well, it would be too late for the Delta flight to pursue a course to another airport and thus the problematic nature of the planning.
Uncle Fred: This statement intrigued me. I assume you are assuming that because so much fuel was dumped, heading for an alternate would have become impossible. Is this reasonable? Under what conditions would a pilot choose to dump so much fuel that reaching an alternate would be impossible? Indeed, this scenario seems to raise the question of whether it is safer for a two-holer with one out ever to choose a dodgy land-ASAP location rather than continuing on on one engine to a far more assured airport.