Japan Air Lines flight 2 "Shiga"
Japan Air Lines's DC-8 named the "Shiga" was perhaps the unintentional precursor to the "Miracle on the Hudson" landing of US Airways Flight 1549. The DC-8 made an amazing, but accidental, splashdown in San Francisco Bay on November 22, 1968.
The NTSB cited "improper application of prescribed procedures to execute an automatic-coupled ILS approach" as the probable cause. The contributing factors included a lack of familiarity of the flight director and autopilot systems. Amazingly, no one was hurt, and the airplane was removed from the water. It went on to serve successfully with Japan Air Lines for many years afterward.
Image credit: Ken Fielding / CC-BY-SA-3.0