Lt. Heiss was pilot of one of six brand new B-25Cs that marked the 3rd Attack Group’s flying debut against Japanese forces. That occurred on April 6, 1942, in a raid on the Japanese airdrome at Gasmata on New Britain. The B-25s dropped nine tons of bombs on the area, setting fuel dumps afire, destroying grounded Japanese aircraft, and blowing up airdrome installations. The group staged through Port Moresby and returned to Charters Towers on April 7 via Horn Island and Cooktown.
Only three days later, Lt. Heiss was one of ten B-25C pilots on the Royce Mission to the Philippines in April, 1942. His co-pilot was Lt. Ed Townsend. Their aircraft was #41-12442. The plane has been on static display as a war memorial on the north coast of New Guinea at a technical training school at Aitape since 1974 and is the only surviving plane that participated in the Royce Mission.
The Royce Mission was a remarkable feat in that Japanese aerial and land-based forces were engaged over the southern Philippines, yet not one of the ten B-25s was lost. All returned safely to Australia at the end of the mission. In addition, the 3rd Attack Group had been flying the B-25s for only two weeks---it was an entirely new plane to them---and yet the Group acquired flying proficiency quickly. Finally, the Royce Mission stretched the outer limits of the range of the B-25C between the Group’s refueling stop at Batchelor Field, NT, and the American base at DelMonte, Mindanao.
Lt. Heiss received the Silver Star for his valor during the Royce Mission. He was awarded an Oak Leaf Cluster for his role in a reconnaissance mission on May 6, 1942, that sighted Japanese naval forces in the Louisiade Archipelago immediately before the Battle of the Coral Sea.