Air Florida Flight 90 (1982)
De-icing is an incredibly important part of flying an airplane. This is why, in 1982, the Boeing 737 crash caused engineers to seriously improve de-icing procedures. Miraculously, only a few survived. For starters, “Though the outside temperature was well below freezing and snow was falling, the crew did not activate the engine anti-ice system that prevents sensors in the engines from freezing and giving incorrect engine power readings.” Those who did survive woke up in the icy waters of a river (Safety Compass).