Hemet Valley Flying Service was a pioneer in the field of aerial firefighting, having converted many aircraft types to airtankers. N13744 / 86 (ex USAF 49-199) was one of four Flying Boxcars this company operated out of their base in southern California. It was acquired by the Castle Air Museum in 1993, and placed on display at Castle AFB, CA. In the early 2000s it was painted in full USAF markings as 49-199.