The thirty passengers were twenty-two Dutch, six German, one British, and one Irish. Among the Dutch was Bert Sas, the diplomat and former military attache to Berlin who in October 1939 had warned the Allies that Germany was preparing to invade France and the Low Countries - intelligence largely ignored at the time, vindicated months later when the Wehrmacht swept west. He had spent the war years in service to the Dutch government in exile and was returning to international duty when his flight ended on a hillside near Prestwick. The aircraft itself, named Nijmegen for the Dutch city, was a four-engine Constellation of the type that defined transatlantic luxury travel in the late 1940s - polished aluminium, triple-tail, the most distinctive airliner of its era. Forty people, two of them children. None survived.

The Nijmegen had been scheduled to depart Schiphol at 8:00 p.m. CET but was delayed loading extra cargo for Iceland, the next stop after Prestwick. She finally lifted off at 9:11 p.m. The forecast Parmentier had been given by the Royal Dutch Meteorological Institute indicated some cloud at Prestwick, likely to dissipate before he arrived. That forecast was wrong. The weather at Prestwick was steadily deteriorating, and no updated bulletin reached the aircraft. Earlier that same evening, two airliners belonging to Scandinavian Airlines System had turned back rather than attempt landings there. Parmentier did not know. The Constellation crossed the English coast at Flamborough Head, tracked northwest, then turned south-southwest fifteen miles east-southeast of Kilmarnock and began its approach to runway 32 - Prestwick's longest and at the time only runway equipped with ground-controlled approach radar.

Inland of the runway the ground rises to over four hundred feet, and three miles to the northeast a set of wireless masts climbs above six hundred. Three miles inland from the runway, electricity pylons carry the main 132,000-volt national grid line for South Scotland. The KLM approach charts the crew were using did not show any of this. They had been copied, the subsequent enquiry discovered to its astonishment, from war-era United States Air Force charts which themselves contained serious errors - in the immediate vicinity the KLM chart gave a spot height of forty-five feet where the actual terrain was over four hundred. Detailed and correct Ordnance Survey maps had been available the whole time. KLM had simply not used them. Parmentier, executing what should have been a routine overshoot and circle to runway 26, climbed to four hundred and fifty feet, lowered the gear, and entered what he believed was an isolated patch of cloud at about 23:32 UTC. It was not isolated. The actual cloud base in places was as low as three hundred feet. He had no way of knowing he was already below the high ground.

The court of enquiry into the crash named several causes. The ground authorities at Prestwick had failed to broadcast updated weather information that would have warned the crew of the falling ceiling. The crew had failed to time their downwind leg correctly for the alternate runway. And the KLM approach chart, copied from a foreign authority's faulty wartime maps when accurate British charts were sitting on a shelf, had hidden from one of the world's most experienced pilots the very obstacles he flew into. The reckoning that followed reshaped airline procedure - approach charts across the industry were rebuilt against national mapping authorities rather than copied from secondhand sources, and weather reporting standards for transatlantic gateways were tightened. None of that brought back the forty people on the Nijmegen. Bert Sas, who had tried to warn the world about a coming catastrophe and watched the world ignore him, died because someone else had decided that an out-of-date chart was good enough.