The A13 Oxygen mask was developed by the US Army Air Force for use by high altitude photo reconnaissance pilots and crew.
During WWII, the US Army Air Force relied on converted fighter and bomber aircraft to fly photo reconnaissance missions over enemy territory.
Stripped of armament and modified with higher performance engines, these planes operated at high altitudes (over 40,000 ft.) to avoid ground defenses and interception by enemy aircraft. Two of the most popular American photo reconnaissance aircraft were the F-4/F-5 and F-6. The F-4 was a factory modified Lockheed P-38 lightning that had its four .50 caliber machine guns and one 20mm cannon replaced with four K-17 cameras. About 120 F-4 and F-4A’s began operating in Australia by April of 1942. The F-4’s were so successful that hundreds of gun equipped P-38 Lightning’s were field modified into photo reconnaissance aircraft and given the designation F-5.
P-51C-5-NT Mustang (F-6C) from the 15th Tactical Reconnaissance Squadron. The plane was flown by Captain John H. Hoefker
When the P-51 Mustang became widely available in early 1944, the Army Air Force converted some for photo reconnaissance use, designating the plane F-6. By the end of the war in Europe, the F-6 was the dominant reconnaissance plane operating in the European Theater of Operations (ETO).
Due to the high altitude that reconnaissance missions were required to be flown at, the Army Air Force needed an oxygen mask that would not leak or freeze at altitudes above 40,000 feet. In January 1944, they developed a pressure-demand mask that would hold positive pressure without oxygen leaks until the wearer exhaled. The mask was designated the A13 oxygen mask.
Although developments of the A13 Mask were generally successful, pilots complained about the mask’s lack of comfort and of having difficulty while speaking at high altitudes due to the mask’s high internal pressure.
Today, A13 Oxygen Masks are sought after collectibles and a reminder of the gallant service of the Army Air Force Photo Reconnaissance Groups.