10 Unsolved Airplane Mysteries

What Does STENDEC Mean?
The aftermath of an airplane crash in 1947. Express/Express/Getty Images

In August 1947, a British airliner containing 11 people took off from Buenos Aires on a flight to Santiago, Chile, and vanished, apparently just a few minutes before landing. The only clue it left was a puzzling Morse code message, "STENDEC," which was the final transmission from the plane. The word was transmitted three times.

Fifty-three years later in 2000, an expedition of searchers finally found the missing plane, which had crashed into a mountain about 31 miles (50 kilometers) from its destination. A glacier had entombed it in ice. Examination of the engines showed no mechanical failure, but accident investigators hit upon another possible explanation. They decided that the plane probably had flown high to avoid bad weather and run into a jet stream, a high-speed wind whose existence had not yet been discovered. That wind would have slowed down the aircraft, so that when it started descending it was not as close to the airport as the pilot thought and so headed toward the mountain. But even so, nobody has ever figured out the meaning of the last message sent by the plane, which for years has defied myriad efforts to decipher it [sources: BBC News, BBC News].