Lieutenant MacKoul joined the Army in November, 1942, trained at Santa Ana and Lemoore Army Air Fields in California, and received his wings at Williams Field, Arizona. He served in the 723rd Bomber Squadron, 450th Bomber Group, Heavy, 15th Air Force in Italy. He served as the Co-pilot on B-24G “Maiden America” #42-78356 during World War II.

On December 25, 1944, after a raid against a supply depot in Innsbruck, Austria, "Maiden America" was on its way back, severely damaged after being hit by flak over the target. With two engines on fire pilot 1st Lt Vincent F. Fagan tried to reach the airport in Basel, Switzerland. Due to fog the crew headed for the airfield in Duebendorf, a town near Zurich. In the Wuerenlingen area Swiss flak – for unknown reasons - opened fire against the crippled bomber. The crew was unable the lower the landing gear and was afraid of shooting flares because gasoline was leaking out of the damaged tanks.

After the B-24 got a direct hit, pilot Fagan ordered the crew to bail out. Then he increased the power of the two remaining engines. Doing so, he avoided that the aircraft crashed right into the village. 2LT MacKoul came down on the nearby "Aare" river and drowned in the ice cold water. This mission was his fifty-second mission. He was temporarily buried in what was then the American Cemetery in Münsingen, Switzerland. His final resting place is in Epinal American Cemetery, Dinozé, France. Lieutenant MacKoul was awarded the Air Medal with two Oak Leaf Clusters, the European-African Middle Eastern Theater Ribbon (ETO) with five Battle Stars, the Purple Heart Medal (PHM), and the Presidential Unit Citation for his part in the bombing of the Ploesti Oil Fields.

Source of information: https://worldwartwoveterans.org, http://www.450thbg.com