WEDNESDAY ON "GMA": In 2009, Captain Sully Sullenberger faced the impossible and saved 155 souls in the successful ‘Miracle on the Hudson’ plane landing. Now, 17 years later, he’s facing another battle: Alzheimer’s. In his first broadcast interview since revealing his diagnosis, Sullenberger sits down with ABC News’ Robin Roberts. Watch the full interview Wednesday, only on Good Morning America. ▻