Originally called the "King Beaver", the de Havilland DHC-3 Otter was designed and built in Canada as a larger brother to the successful de Havilland Beaver. It could be equipped with wheels, floats, skis or low-pressure, overize rough terrain tires. It had excellent Short Takeoff and Landing capabilities and could operate from a 305m (1,000ft) landing strip. It carred twice the payload of the Beaver, its floor was reinforced for heavy cargo and it could carry 14 passengers. A double frieght loading door on one side of the aircraft allowed the handling of awkward loads. The cabin seats could be folded against the cabin walls to accomodate cargo. The prototype flew in 1951 and the first production aircraft was delivered to Hudson Bay Mining & Smelting Ltd. A total of 466 Otters were built before production ended in 1967. The Otter was utilized in over 36 countries. The U.S. Army was the largest operator taking delivery of 227 aircraft starting in 1955. It was used by the US navy, Belgium and Britain for Antarctic exploration. The Royal Canadian Air Force operated 66 Otters in the Transport and SAR role. Many ex-military machines gained a 2nd life with civilian operators around the world. The Otter was extensively used in aerial waterbombing development and STOL expirements.