The CH-135 Twin Huey was based on the on a enlarged version of the CH-113 Iroquois (which was nicknamed the “Huey”), using two Pratt & Whitney Canada PT6T-2 engines. In 1968, the Government of Canada approved the development of the CH-135. The Canadian Government had helped fund the development of the engines and was hoping to have them used in the Canadian Armed Forces as well as marketing them to other countries. The project was very successful in that it helped improve the CH-113 Iroquois in many ways: it could carry more cargo or troops, it was more powerful and the second engine provided a backup in case one engine was inoperative.

The success of the CH-135 Twin Huey led to the Canadian government placing an order for 50 helicopters, which started service in 1973. The CH-135s were used mainly for the support of army field troops and operations. In many cases, the CH-135s worked in conjunction with the Kiowa helicopters.

The Twin Hueys were retired from the Canadian Forces starting in 1996 and were struck off strength in December 1999. Of the surviving CH-135s, 41 were purchased by the US government in December 1999. These CH-135s where then transferred to the National Army of Colombia and Colombian National Police.

CH-135 Twin Huey helicopters were used primarily on army bases and often took part in United Nations peacekeeping missions. Tail number 135102 served with the 427 “Lion” Squadron, a tactical helicopter squadron based in Petawawa, Ontario. It served with the 427 in Egypt (1987, Multinational Force and Observers), Honduras (UN, 1989) and Haiti (UN, 1995). It is painted in the white colour scheme that it wore during its United Nations missions.

The Twin Hueys were declared surplus in 1995 and, along with the Iroquois (single-engine Hueys), were replaced by CH-146 Griffons. Tail number 135102 was stored at Canadian Forces Station Mountainview before being donated to the Museum. It was loaded onto a flatbed truck to be taken to the Museum on November 5, 1996, but on arrival in Trenton, its tail became entangled in overhead wires while going down Dundas Street West. There was little damage to the wires or the tail, but traffic lights were out for 90 minutes while the situation was sorted out. A new tail rotor blade was donated by Eagle Copters Limited.