During the late 1920s and early 1930s, the Air Corps intended to buy several aircraft specially designed for aeromedical evacuation and crash rescue & recovery missions. Unfortunately, the very limited procurement budgets delayed these plans so the Army settled for conversion of existing aircraft. In the spring of 1931, one Y1C-14 (S/N 31-389) was refitted for duty as an air ambulance.

The passenger compartment was converted to handle three basket litter patients. Additionally, the plane carried a flight surgeon and a medical attendant to handle patient care in flight. Finally, the forwar area of the compartment was fitted with several medical supply cabinets, medical emergency kits, and miscellaneous supplies (e.g. food and hot coffee).

The Y1C-15 was very effective in the aeromedical evacuation mission when flying from one air field to another; however, it was to big and heavy to fly from small unimproved fields. Because of this, the plane could not be used for emergency recovery of air crash victims or battlefield casualties.

The Y1C-15 was one of a series of cargo-series aircraft converted for air ambulance duties - others include in the Douglas C-1, Ford C-3/C-9 and later the American C-24.