In July 1944, on his second combat tour, he was shot down, evaded capture, and successfully returned to the Allied lines in September 1944.

Later in his life, he would lead the campaign to establish the Commander-in-Chief's Trophy, the annual football competition between the three U.S. service academies.

In June 1965 following an assignment as commander of the Tactical Fighter Weapons Center, Nellis Air Force Base, Nevada, he went to Southeast Asia.

[2] From Southeast Asia, Simler was assigned to Headquarters U.S. Air Force, where he became director of operations in August 1967.

[2] Simler, along with his aide Captain Gil L. Gillespie, was killed in the crash of a T-38 Talon jet trainer on takeoff at Randolph Air Force Base, Texas, on September 9, 1972.