Take-off from Schiphol was planned at 20:00 on 20 October 1948 for a flight to New York via Prestwick, with as alternative Shannon, Ireland. The Constellation PH-TEN Nijmegen, with thirty passengers aboard, carried enough fuel to return to Amsterdam after such a diversion. Weather for Prestwick was bad, but improving, according to the forecast; in actual fact, conditions were deteriorating. Take-off was delayed to 21:10 while additional cargo was loaded for Iceland, with an extra stop planned. Because of this delay, the wireless operator missed (by five minutes) a Prestwick radio message advising of rain and a 600 feet cloud base.
Under these conditions, in combination with a 20 knot cross-wind on the main runway, KLM-pilots were forbidden to land at Prestwick, instructions drafted by chief pilot Parmentier himself.