The Boeing CC-137 is a retired transport and tanker aircraft which served with the Canadian Forces from 1970 to 1997. The Boeing 707-347C aircraft provided long range passenger transport for the military, VIP transport for government and air-to-air refueling for fighters such as the CF-116 Freedom Fighter and CF-18 Hornet. It was replaced by the Airbus CC-150 Polaris in the transport role and much later in the tanker role.
During the 1960s, the Royal Canadian Air Force set out a requirement to replace the aging fleet of Canadair CC-106 Yukons and Canadair CC-109 Cosmopolitan transports. Initially, the Boeing KC-135 was being considered because the versatile design could also fulfill a yet-unspecified aerial refuelling role.[1] Although a "purpose-built" aircraft would have suited the RCAF requirements better, an opportunity to acquire Boeing 707s as an alternative, soon presented itself.[2]
Canada purchased five Boeing 707s in 1970–71 to replace the RCAF's CC-106 Yukons in the long range transport role and the CC-109 Cosmopolitan as an executive or short-range transport.[3] The first four aircraft had been built for Western Airlines, but that order was subsequently cancelled; the fifth was bought separately a year later. To fulfil Canada's requirements for aerial refueling, two aircraft were fitted with Beechcraft made probe and drogue refueling pods in 1972.[4] The two sets of refuelling equipment were moved from aircraft to aircraft to keep fleet utilization even between the airframes.
The CC-137 fleet had a combined total of 191,154 hours, remaining in service in the transport role until 1995, with two aircraft continuing in use as tankers until 1997.[4] [5]
Most of the fleet ended up with the Northrop Grumman E-8 Joint STARS programme either for spare parts or conversion to E-8C standard for the United States Air Force.[6]