IF the pilot had taken the same route as he did in the morning
IF they'd flown from Sukarno-hata and not Halim......
Actually I would replace those with something a lot more basic - something not connected with a mere 'chance':
If the crew had a map of terrain they were flying over. There was a navigator aboard and he did not even bother to have an aeronautical chart of the area, makes you wonder what he was paid for.