The de Havilland Canada DHC-5 Buffalo is a short takeoff and landing (STOL) utility transport turboprop aircraft developed from the earlier piston-powered DHC-4 Caribou.

The Buffalo arose from a 1962 United States Army requirement for a STOL transport capable of carrying the same payload as the CH-47A Chinook helicopter.

No further US orders followed, however, as at the start of 1967 (See the Johnson-McConnell agreement of 1966), inter-service politics led to large fixed-wing transports being transferred to the United States Air Force,[2] who considered themselves adequately equipped with the Fairchild C-123 Provider.

In December 2008, Viking Air indicated their intention to put the Buffalo series back into production at their home factory in Victoria, British Columbia or in Calgary, Alberta.

[9] In late 1965, one of the prototype DHC-5s operated by the U.S. Army was deployed to Bien Hoa Air Base in South Vietnam for a three-month evaluation period, assigned to the 2nd Flight Platoon of the 92nd Aviation Company.

On 9 August 1974, Canadian Forces CC-115 Buffalo 115461 was shot down by a Syrian surface-to-air missile, killing all nine CF personnel on board.

[11] In 1975, the Buffalo dropped its tactical transport role and was converted to domestic search and rescue, except for a few that kept serving on UN missions.

The number of aircraft have been reduced to eight, with six on active service, one in storage (recently dismantled) and one used for battle damage training.

[13] However, after changes in Canada's defence budget as well as accusations of bias from the aerospace industry,[citation needed] the Buffalo replacement program was relaunched as an open competition.

A cooperative NASA/Canadian Government research program on augmentor wing concepts started in 1965 and culminated in the need for a proof-of-concept aircraft.

It also had full-span leading edge slats, blown ailerons and double-surface flaps enclosing a venturi-shaped passage.

The usual turboprop engines were replaced with Rolls-Royce Spey 801 SF (Split Flow) bypass engines with a new bypass duct which separated the hot and cold flows to provide both propulsion and augmentor airflow to the powered lift system.

[17][18][23]: 153 [24][25][26] Boeing designed and installed an experimental swept, supercritical wing incorporating a boundary layer control system.

[25]: 9–10  In 1980, this aircraft participated in carrier trials aboard USS Kitty Hawk, demonstrating STOL performance without the use of catapults or arrestor gear.

[27] After demonstrations by Bell aircraft using a Lake LA-4 light amphibian with Air Cushion Landing Gear the development of this type of gear was pursued in a joint effort between the USAF and the Canadian Government by retrofitting a similar system to a medium cargo transport, a Buffalo.

442 Transport and Rescue Squadron based in Comox, BC, until the type was finally retired in 2022 after 55 years of service.