de Havilland Canada DHC-6 Twin Otter

de Havilland Canada DHC-6 Twin Otter
Name	de Havilland Canada DHC-6 Twin Otter
Caption	A Twin Otter in flight
Type	Utility aircraft, STOL
National origin	Canada
Manufacturer	de Havilland Canada
First flight	20 May 1965
Introduction	1966
Status	In service
Primary user	Various civil and military operators worldwide
Produced	1965–1988, 2008–present
Number built	844 (original production) + new production
Developed from	de Havilland Canada DHC-3 Otter

de Havilland Canada DHC-6 Twin Otter is a Canadian STOL utility aircraft developed by de Havilland Canada and renowned for its ruggedness and versatility. It is a twin-engine, high-wing, unpressurized turboprop aircraft capable of operating from short, unprepared airstrips. Since its introduction, it has become a workhorse for operators in remote regions, serving roles in scheduled air transport, bush flying, skydiving, and scientific research.

Development and design

The aircraft was conceived in the early 1960s as a twin-engine development of the successful single-engine de Havilland Canada DHC-3 Otter, intended to offer improved performance and safety for operators in demanding environments. The design team at de Havilland Canada in Downsview, Ontario, focused on creating an aircraft with exceptional short takeoff and landing (STOL) capabilities. Key features included a robust, fixed tricycle landing gear, a large double-slotted Fowler flap system, and initially, Pratt & Whitney Canada PT6A turboprop engines. The prototype, designated the DHC-6-100, first flew from the company's facility at Toronto's Downsview Airport on 20 May 1965. The design emphasized simplicity, durability, and ease of maintenance, making it ideal for operations in areas with limited infrastructure, such as the Canadian Arctic, the Andes, and Southeast Asia.

Operational history

Entering service in 1966 with Airwest (later Harbour Air) and NorOntair, the aircraft quickly proved its worth. It became indispensable for regional airlines serving remote communities, notably for carriers like Air Inuit, First Air, and Kenn Borek Air in Canada. Its global footprint expanded rapidly, with significant use in Antarctica by organizations such as the British Antarctic Survey and the United States Antarctic Program. Military operators, including the Canadian Forces and the United States Army, have used it for transport and paratrooper training. The aircraft's reliability in extreme conditions has led to continuous demand, prompting the restart of production in 2008 by Viking Air (now De Havilland Aircraft of Canada Limited) in Calgary, Alberta.

Variants

Three main series were produced during the original production run. The initial Series 100 featured a shorter fuselage and less powerful engines. The improved Series 200, introduced in 1968, offered more powerful Pratt & Whitney Canada PT6A-27 engines and increased maximum takeoff weight. The definitive Series 300, launched in 1969, incorporated a longer fuselage, greater fuel capacity, and more powerful engine options, becoming the most produced variant. The modernized Series 400, produced since 2008 by De Havilland Aircraft of Canada Limited, features advanced avionics such as the Garmin G1000 glass cockpit, upgraded Pratt & Whitney Canada PT6A-34 engines, and improved interior configurations.

Operators

The aircraft has been operated by a vast array of civil and military entities across six continents. Major civil operators have included Air Greenland, Buffalo Airways, Trans Maldivian Airways, and Widerøe. Military and government operators span the Royal Canadian Air Force (designated the CC-138), the United States Army (as the UV-18), the Swedish Air Force, the Botswana Defence Force, and the Philippine Air Force. It is also widely used by parachute clubs and scientific organizations globally.

Specifications (DHC-6 Series 400)

* **Crew:** 1–2 * **Capacity:** 19 passengers * **Length:** 15.77 m (51 ft 9 in) * **Wingspan:** 19.81 m (65 ft 0 in) * **Height:** 5.94 m (19 ft 6 in) * **Empty weight:** 3,660 kg (8,069 lb) * **Max takeoff weight:** 5,670 kg (12,500 lb) * **Powerplant:** 2 × Pratt & Whitney Canada PT6A-34 turboprop engines * **Maximum speed:** 338 km/h (210 mph, 182 kn) * **Range:** 1,297 km (806 mi, 700 nmi) * **Service ceiling:** 8,140 m (26,700 ft) * **Takeoff distance:** 335 m (1,100 ft)

Accidents and incidents

Despite its rugged design, the aircraft has been involved in numerous accidents over its long service life. Notable incidents include the 1991 crash of LADE Flight 508 in Argentina, the 2013 crash of a Kenn Borek Air flight in Antarctica, and the 2019 crash of a Mountain Air Service aircraft in Nepal. Causes have ranged from controlled flight into terrain and severe weather to mechanical failures. Its extensive use in challenging environments inherently exposes it to higher operational risks compared to aircraft operating primarily from major airports like Heathrow Airport or O'Hare International Airport.

Category:Aircraft manufactured in Canada Category:STOL aircraft Category:Twin-turboprop aircraft