Eleven lives were folded into that aircraft. The captain, Reginald Cook, had flown bombers through the Second World War and wore the Distinguished Service Order and Distinguished Flying Cross; his crew were RAF veterans too, men who had survived a war only to disappear on a peacetime crossing. Iris Evans, the flight attendant, had served as a chief petty officer in the Women's Royal Naval Service. The six passengers were ordinary travelers with ordinary errands: a British diplomatic courier carrying official papers, businessmen, a representative for the tire-maker Dunlop. One woman, Marta Limpert, was said to be bringing home the ashes of her late husband. They were not adventurers chasing a dangerous summit. They were people on the last leg of a long flight from London, expecting dinner in Santiago.

To reach Chile, Star Dust had to climb above 24,000 feet and thread the highest wall of the Andes in thick winter cloud, with no sight of the ground below. The crew navigated by dead reckoning - time, speed, and heading - and they were confident they had cleared the peaks. They were wrong. The aircraft had flown into the jet stream, a band of high-altitude wind that in 1947 was barely understood. Blowing hard from the west, it became a fierce headwind, slowing the plane's progress over the ground while the crew believed they were racing ahead. Thinking the mountains were behind them, they began their descent into a sky that was still full of mountain.

Star Dust struck a near-vertical snowfield high on the Tupungato Glacier at almost cruising speed, its landing gear still tucked away - a plane flying confidently into terrain it could not see. The impact triggered an avalanche that buried the wreckage in seconds. Within days the compacted snow had hardened into ice, and the airliner became part of the glacier itself. Air Vice Marshal Don Bennett, who led British South American Airways, personally directed a five-day search and found nothing. The mountain had swallowed the evidence so completely that whispers of sabotage and stranger things filled the silence. The plain truth was colder: the dead lay frozen inside a moving river of ice.

Glaciers do not keep what they take forever. Between 1998 and 2000, Argentine climbers near Tupungato began finding pieces of Star Dust emerging far down the mountain - a wheel, an engine, fragments of the past delivered by decades of glacial creep. Investigators could finally reconstruct what had happened, and clear Captain Cook's name of any blame. As for STENDEC, the explanations never stop coming. It is an anagram of DESCENT; perhaps a hypoxic, oxygen-starved operator garbled the word. Perhaps it was an abbreviation no one recorded. The most haunting answer may be that there is no answer - just seven letters tapped out above the clouds, moments before a young man and ten others slipped beyond reach.