William Bernhardt Petersen was born on October 17, 1892. He was the son of Peter Ferdinand Petersen and Petra Albine Danielsen Petersen.

Petersen graduated from Central High School and attended the University of Chicago when war was declared. He served in the Aviation Section of the Aero Squadron as a First Lieutenant and a pilot during World War I. Petersen and Benfiel were student aviators at the Gunnery School for Aviation in Cazeaux, France. They both started in single-seat Newport machines with instructions to practice firing at two captive balloons. When Benfiel landed, Petersen was still in the air performing feats seldom seen at the school. He was executing a steep bank when his machine gun jammed. He paid more attention to this than to his ship. He side-slipped and made a futile attempt to right himself and crashed. He died in an air crash on July 3, 1918, and he was buried at a French cemetery and later transferred to Forest Lawn Memorial Park, Omaha, Douglas County, Nebraska, USA. The inscribed unit of his death date on his headstone is July 2, 1918.

Source of information: www.findagrave.com