The STENDEC mystery

A recent blog post from Nick Redfern About That "STENDEC" Puzzle reminded me of this fascinating mystery from 1947, two years after the end of the Second World War. A British Lancastrian airliner—a civilian version of the legendary Lancaster bomber—crashed in the Andes in poor weather shortly after sending a message in Morse code to the air traffic controller at the flight’s destination in Santiago, Chile. The message was routine except for its final word: STENDEC. And that’s the start and the end of the mystery: what on Earth does STENDEC mean?

I find the STENDEC mystery fascinating... but equally fascinating are the different approaches taken by the huge number of armchair mystery solvers who have turned their attention to it. Some people clearly want their unsolved mysteries to remain unsolved forever, so any new piece of evidence is described as “deepening the STENDEC mystery” rather than helping to elucidate it. Other people approach the problem as if it was deliberately contrived by the radio operator to be a puzzle for future generations. In reality, aircraft radio operators don’t suddenly start talking in anagrams or cryptograms as if they were characters in a Mensa brain teaser! It’s not beyond the bounds of possibility, as many people have suggested, that the aircraft came under attack from a hostile UFO. What is beyond the bounds of possibility is that the radio operator would signal this fact to the world using the single, unknown, word STENDEC. Even if he could see the word stencilled on the fuselage of the UFO, it’s difficult to believe he would imagine it was the most effective way to get his last, desperate message across.

Except in very unusual circumstances, a professional radio operator will always be trying to get factual information across to the recipient as clearly and concisely as possible. This was even more true in the days of low bandwidth, low signal-to-noise Morse telegraphy. In the case of “STENDEC”, the operator knew the Santiago controller was having difficulty understanding him, because he was asked to repeat the word—which he did, twice, using exactly the same Morse code. He didn’t repeat the message in a less cryptic form, as might be expected, or more slowly—it’s described as being sent “very fast”. So why might the operator have persisted in sending a message he knew the person at the other end was having difficulty understanding?

One possibility is that the operator was deliberately winding up the air traffic controller with meaningless gibberish, or a Sunday Times style brainteaser. However, it’s highly unlikely the operator would do this with a complete stranger, particularly if he wanted to keep his job. Furthermore, being in a WW2-vintage aircraft over a mountain range in bad weather isn’t the time for fooling around. A second possibility, which has been suggested by some people, is that the crew were in a delirious state due to a fault in their oxygen supply—essentially that the operator thought he was making sense when he wasn’t. But if that was the case, why was the preceding part of the message (confirming the flight’s destination and expected time of arrival) perfectly clear and sober? The only other reason for sending a superficially meaningless message is if it is a codeword—something that would mean nothing to an eavesdropper but would be perfectly understandable to the intended recipient, who would be in possession of the same set of codes as the sender.

This is where the STENDEC story—or rather the story of its armchair puzzle solvers—takes a really bizarre turn. It was “revealed” on the internet about ten years ago that STE–ND–EC was a code signal (or rather the concatenation of three code signals) used by the RAF during WW2 to mean “Severe Turbulence Encountered – Now Descending – Expecting Crash”. The Lancastrian’s radio operator was an ex-RAF man, and WW2 had finished just two years earlier. If STENDEC really was a widely used wartime RAF code, then the operator would have known it. The revelation doesn’t “deepen” the STENDEC mystery or “add a new dimension” to it, as many people would dearly love—it destroys the mystery altogether. The beginning and end of the STENDEC mystery is that the word is meaningless in any known language. If it was a codeword used by the RAF, then it wasn’t meaningless (at least, not to the operator who used it) and so the mystery goes away.

The Chilean air traffic controller didn’t understand the codeword, despite it being repeated three times, for the simple reason that he had never come across it before. Chile wasn’t one of the wartime allies -- it was a neutral country. Presumably the Lancastrian’s operator, in the heat of the moment, forgot that. But it all hinges on whether “Severe Turbulence Encountered – Now Descending – Expecting Crash” was a real RAF code from WW2, or a schoolboy’s internet hoax of the 21st century.

This is a good example of people wanting their mysteries to remain mysteries. It would be easy enough for a serious STENDEC researcher—if there is such a thing—to look through all the old RAF codebooks in the National Archives. Either STENDEC is there or it isn’t. If it is there, the mystery evaporates and nothing else needs to be said about it. If it isn’t there, then the “astonishing internet revelation” was a hoax, and shouldn’t ever be referred to except as a hoax. Personally, I suspect it is a hoax, because a straight acronym of this type strikes me as more in keeping with 21st century texting that wartime Morse code. Also, it defies belief that the operator would send his estimated time of arrival in Santiago seconds before saying he was expecting a crash.

But real mystery lovers don’t want a resolution to the mystery. They want to deepen the mystery and add dimensions to it. They don’t want to know for certain that “Severe Turbulence Encountered – Now Descending – Expecting Crash” was an established WW2 code, or that it was a schoolboy hoax. And I have to say I agree with them!