On May 18, 1944, Eloise was on a routine C-40 flight between the western coast of Bougainville and Guadalcanal. The plane was carrying wounded men including officers and parcels of mail. The plane never arrived at its destination.  No evidence of wreckage or remains was ever discovered.
Eloise's fellow nurse, Helen Hunter, had been angling to catch that flight to get to Guadalcanal where her boyfriend, Bob Weant, was stationed as a pilot.  There was a dance that night and they had a date.  Alas she missed the flight and Eloise was destined to take her place.

The Story of Eloise Richardson
 http://userpages.aug.com/captbarb/mia.html