This aircraft was born for a US Army requirement for a plane to have similar payload as a CH-47 Chinook. The plane would need STOL capabilities and operate on low quality airfields. For this DHC would take thier DHC 4 Caribou, a STOL transport already in use with the army, and gave it a makeover. They enlarged it, added a new wing and the cruciform tail would become a t-tail. The powerplant recieved the biggest change; the outdated PW R2000 radials gave way to the GE T64 Turboprops. Due to these modifications, the plane was able to carry a higher payload while at the same have better STOL performance than the Caribou. The plane has an 18,000 pound payload and can operate on a runway that is only 3,000ft long.