In their drive to open up a transcontinental flyway, postal officials were constantly seeking better, faster aircraft for their pilots to use. The airmail service had tested several airplanes besides the JN-4 and de Havilland 4, but no real alternative aircraft had been found. When a determination was made to reconfigure the de Havilland aircraft by adding a a second engine, postal officials believed they had found their airplane.
The first test flights of this aircraft were positive, and 15 twin de Havillands were ordered. Unfortunately for pilots and officials, the test flights did not reflect the problems the airplane would develop when used by postal aviators.
Twin engine de Havilland in snowstorm.