De Havilland Canada

DHC-6 Twin Otter

The DHC-6 Twin Otter is a twin-engine, turboprop short take-off and landing (STOL) passenger / utility aircraft seating up to 20 passengers. It was a twin-engine replacement for the single-engine DHC-3 Otter retaining that type’s excellent short take-off and landing capabilities.

 

The type is designed for operation from unimproved strips and can be configured with wheel, ski, float or amphibious float tricycle landing gear arrangements.

 

Its high rate of climb and descent make it popular with a wide variety of operators ranging from Skydiving Clubs to Medivac Units.

 

 

The prototype (CF-DHC-X) was flown for the first time on 20th May 1965.

 

The Twin Otter was produced in three variants, the Series 100 (two 550shp PT6A-20), Series 200 (with lengthened nose and additional baggage capacity) and the Series 300 (two 620shp PT6A-27A engines). The first six aircraft produced were designated Series 1, indicating that they were prototypes and development aircraft. The initial production run the consisted of Series 100 aircraft (Serial numbers 7 to 115).

 

The Series 200 production began in 1968 (Serial numbers from 116 to 230) and featured an extended nose for extra baggage storage as well as a larger rear baggage door.

 

 

The Series 300 was introduced in 1969 (beginning with serial number 231) and it was this configuration which proved to be the most successful variant. Payload and performance was further improved with the fitting of thePT6A-27 engine. Some 614 Series 300 aircraft were built at Downsville by De Havilland Canada before production ended in 1988. 

 

A total of 6 prototypes and 844 production aircraft were built by De Havilland Canada and the type still continues in service worldwide (literally from the Arctic to the Antarctic) with both civil and military operators. Significant fleets were operated in countries including Norway (Widerøe), the Maldives, United States (several operators including Rocky Mountain Airways, Alaska Airlines, Wien Air Alaska, Ozark, Scenic Airlines), Canada (Wardair, Pacific Western Airlines, Time Air), Mexico and Australia (Ansett and TAA).

 

The Twin Otter has been widely used in Antarctica, Four Twin Otters are used by the British Antarctic Survey and several also provide support the United States Antarctic Program, operated by Kenn Borek Air.

 

 

After De Havlland ceased production in Canada, tooling was acquired by Viking Air of British Columbia who produced replacement parts and components for existing aircraft. 

 

In 2006, Viking Air purchased the type certificate for DHC-6 Twin Otter from Bombardier Aerospace. Subsequently, they also purchased the type certificates for all of the 'out-of-production' De Havilland Canada aircraft (DHC-1 through DHC-7).

 

 

In September 2006, Viking announced its intention to produce a Series 400 aircraft with 27 orders already secured.  By November 2007, this had grown to 40 firm orders and so Viking Air put the Twin Otter back into production as the Twin Otter Series 400 with more powerful PT6A-34/35 engines.

 

A demonstrator (C-FDHT) was flown for the first time on 1st October 2008 and the first production aircraft (serial number 845) followed on February 16th 2010.

 

The 100th Series 400 (serial 944) was displayed at the July 2017 EAA AirVenture Oshkosh.

 

38% of existing aircraft are now operated as Regional Airliners, 31% are in military aviation or special missions, 26% are in industrial support and the remaining 5% are in private air charter.

 

It is reported that, of these, 70 are on regular landing gear wheels, 18 are configured as straight or amphibious floatplanes, 10 have low-pressure over-size ‘tundra’ tyres and 2 aircraft have wheel skis.

 

By July 2017, production of the Series 400 exceeded 125 aircraft.