Complex sentence: The crew not only survived the crash but also managed to swim ashore and later find their way to the overland rescue convoy with the rest of the survivors, who eventually reached Windhoek on Christmas Eve, 26 days after the original disaster.
Split into simpler sentences: The crew not only survived the crash but also managed to swim ashore and later find their way to the overland rescue convoy. The airmen, together with the original survivors, eventually reached Windhoek on Christmas Eve, 26 days after the original disaster.