On 2 August 1947 a Lancastrian airliner crashed in the Andes. No traces of the aircraft were found in contemporary searches, but 50 years later the mystery was largely solved when bits of Lancastrian, and the remains of most of the passengers and crew were spat out by the Tupungato glacier. All on board had been killed in what (for those days) was a very common type of accident - flying into a hill in cloud.
A mystery remains however: the official record suggests that the last radio transmission from the aircraft (in morse code) was ETA [estimated time of arrival] Santiago 17.45 hrs STENDEC.
This message was clearly odd, because to this day no-one can begin to understand what STENDEC might have meant. It was repeated three times, very fast but apparently clearly. There is however another oddity. The message was received at 17.41, which means that the crew apparently believed themselves to be four minutes from touchdown.
This is however impossible if the crew had the slightest idea of their altitude. Current estimates are that the aircraft hit the ground at about 15,000 feet above sea level. Santiago is around 1,500 feet above sea level. In an unpressurised aircraft, 500 ft a minute is a comfortable rate of descent with passengers on board. Even if they pushed it to 1000 feet a minute the descent alone, quite apart from manoeuvring for landing, would take 15 minutes or so. Either the altimeter readings were way off or the last radio message was transcribed wrongly.
We know from accounts of WWII bomber operations that icing was a serious and sometimes fatal hazard. From contemporary photos, the Lancastrian did not appear to have any de-icing equipment, which would have made airframe icing a grave danger. If severe icing was encountered, the only way out was down - a problem if you are over high terrain in cloud.
If part of the message (the ETA) was wrong, the STENDEC bit could be wrong too. If you look at the morse for STENDEC and the morse for the word ICING with the letter separators changed, there is a lot of similarity:
... - . -. -.. . -.-. (Stendec)
.. - . -. .. -. - -. (Icing)
Futhermore, Icing is the only word that I can think of which could stand on it's own and not need to be part of a longer sentence or phrase like fuel low or engine losing power. If it had happened the radio operator would have understood the peril, which would explain the rapid repetition. It all fits, although we shall never know for sure.