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de Havilland Canada DHC-6 Twin Otter

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DHC-6 Twin Otter
Winair DHC-6 Twin Otter landing at Gustaf III Airport
Role Utility aircraft
Manufacturer de Havilland Canada
Viking Air
First flight 20 May 1965
Introduction 1966
Status In production[1]
Produced 1965–1988 (Series 100–300)
2008–present (Series 400)
2023–present (Series 300-G)
Number built December 2019: 985
(844 DHC, 141 Viking)[2]
Developed from de Havilland Canada DHC-3 Otter

The de Havilland Canada DHC-6 Twin Otter is a Canadian STOL (Short Takeoff and Landing) utility aircraft developed by de Havilland Canada in the mid-1960s and still in production today. De Havilland Canada produced it from 1965 to 1988; Viking Air purchased the type certificate, then restarted production in 2008 before re-adopting the DHC name in 2022. In 2023 DHC restarted production of the 300 series, in addition to the Series 400 produced by Viking. The aircraft's fixed tricycle undercarriage, STOL capabilities, twin turboprop engines and high rate of climb have made it a successful commuter airliner, typically seating 18–20 passengers, as well as a cargo and medical evacuation aircraft. In addition, the Twin Otter has been popular with commercial skydiving operations, and is used by the United States Army Parachute Team and the 98th Flying Training Squadron of the United States Air Force.

Design and development

[edit]
Aerovías DAP DHC-6 Series 300 at Puerto Williams
A Twin Otter making a normal landing approach in Queensland
First flight of the Series 400 technical demonstrator by Viking Air at Victoria Airport, 1 October 2008

Development of the aircraft began in 1964, with the first flight on 20 May 1965. A twin-engine replacement for the single-engine DHC-3 Otter retaining DHC's STOL qualities, its design features included double-slotted trailing-edge flaps and ailerons that work in unison with the flaps to boost STOL performance. The availability of the 550 shaft horsepower (410 kW) Pratt & Whitney Canada PT6A-20 turboprop in the early 1960s made the concept of a twin more feasible. A DHC-3 Otter with its piston engine replaced with two PT6A-4[3] engines had already flown in 1963. It had been extensively modified for STOL research.[4] To bush plane operators, the improved reliability of turboprop power and the improved performance of a twin-engine configuration made it an immediately popular alternative to the piston-powered Otter which had been flying since 1951.

The first six aircraft produced were designated Series 1, indicating that they were prototype aircraft. The initial production run consisted of Series 100 aircraft, serial numbers seven to 115 inclusive. In 1968, Series 200 production began with serial number 116. Changes made at the beginning of Series 200 production included improving the STOL performance, adding a longer nose that was equipped with a larger baggage compartment (except for aircraft fitted with floats), and fitting a larger door to the rear baggage compartment. All Series 1, 100, and 200 aircraft and their variants (110, 210) were fitted with the 550 shp (410 kW) PT6A-20 engines.

In 1969, the Series 300 was introduced, beginning with serial number 231. Both aircraft performance and payload were improved by fitting more powerful PT6A-27 engines. This was a 680 hp (510 kW) engine that was flat rated to 620 hp (460 kW) for use in the Series 300 Twin Otter. The Series 300 proved to be the most successful variant by far, with 614 Series 300 aircraft and their subvariants (Series 310 for United Kingdom operators, Series 320 for Australian operators, etc.) sold before production in Toronto by de Havilland Canada ended in 1988.

In 1972, its unit cost was US$680,000,[5] In 1976, a new -300 would have cost $700,000 ($3 million 31 years later) and is still worth more than $2.5 million in 2018 despite the -400 introduction, many years after the -300 production ceased.[6] 844 had been produced by the time the first production end run ended in 1988.[7][8]

New production

[edit]

After Series 300 production ended, the remaining tooling was purchased by Viking Air of Victoria, British Columbia, which manufactures replacement parts for all of the out-of-production de Havilland Canada aircraft. On 24 February 2006, Viking purchased the type certificates from Bombardier Aviation for all the out-of-production de Havilland Canada aircraft (DHC-1 through DHC-7).[9] The ownership of the certificates gives Viking the exclusive right to manufacture new aircraft.

On 17 July 2006, at the Farnborough Airshow, Viking Air announced its intention to offer a Series 400 Twin Otter. On 2 April 2007, Viking announced that with 27 orders and options in hand, it was restarting production of the Twin Otter, equipped with more powerful Pratt & Whitney Canada PT6A-34 engines.[10] As of November 2007, 40 firm orders and 10 options had been taken and a new final assembly plant was established in Calgary, Alberta.[11][12] Zimex Aviation of Switzerland received the first new production aircraft, serial number 845, in July 2010.[13][14] By mid-2014, Viking had built 55 new aircraft at its Calgary facility. The production rate as of summer 2014 was about 24 aircraft per year. In April 2015, Viking announced a reduction of the production rate to 18 aircraft per year.[15] On 17 June 2015, Viking further announced a partnership with a Chinese firm, Reignwood Aviation Group. The group will purchase 50 aircraft and become the exclusive representatives for new Series 400 Twin Otters in China.

Major changes introduced with the Series 400 include Honeywell Primus Apex fully integrated avionics, deletion of the AC electrical system, deletion of the beta backup system, modernization of the electrical and lighting systems, and use of composites for non load-bearing structures such as doors.[16]

The 100th Series 400 Twin Otter (MSN 944) was displayed at the July 2017 EAA AirVenture Oshkosh. Currently, 38% are operated as regional airliners, 31% in military aviation or special missions, 26% in industrial support and 5% in private air charter. Additionally, 70 are on regular landing gear wheels, 18 are configured as straight or amphibious floatplanes, 10 have tundra tires and 2 have wheel skis.[17]

In 2019, Viking started making plastic components for the Twin Otter by 3D printer to help reduce cost.[18] Twin Otter production was suspended in 2019 during the COVID-19 pandemic. In July 2022, DHC announced that it was reviewing the program and supply chain, with a decision on when to resume production expected "in the near future".[19] In 2023, its equipped price was $7.25M.[20]

In June 2023 Viking, now operating as De Haviland Canada started production of new DHC-6 Classic 300-G.[8]

Operational history

[edit]
A Trans Maldivian Airways Twin Otter at Velana International Airport
Maldivian DHC-6 Twin Otter water landing
De Havilland Canada DHC-6 Twin Otter on Beechey Island at the graves of seamen who were part of Franklin's lost expedition (Nunavut, Canada) circa 1997. Note the tundra tires.
Twin Otter daily scheduled service between Glasgow (Scotland) and Barra Airport's sandy beach runway

Twin Otters could be delivered directly from the factory with floats, skis, or tricycle landing gear fittings, making them adaptable bush planes for remote and northern areas. Areas including Canada and the United States, (specifically Alaska) had much of the demand. Many Twin Otters still serve in the Arctic and subarctic, but they can also be found in Africa, Australia, Asia, Antarctica, and other regions where bush planes are the optimum means of travel. Their versatility and manoeuvrability have made them popular in areas with difficult flying environments such as Papua New Guinea. In Norway, the Twin Otter paved the way for the network of short-field airports, connecting rural areas with larger towns. The Twin Otter showed outstanding reliability, and remained in service until 2000 on certain routes. Widerøe of Norway was, at one time, the world's largest operator of Twin Otters. During one period of its tenure in Norway, the Twin Otter fleet achieved over 96,000 cycles (take-off, flight, and landing) per year.[citation needed]

A number of commuter airlines in the United States got their start by operating Twin Otters in scheduled passenger operations. Houston Metro Airlines (which later changed its name to Metro Airlines) constructed their own STOLport airstrip with a passenger terminal and maintenance hangar in Clear Lake City, Texas, near the Johnson Space Center. The Clear Lake City STOLport was specifically designed for Twin Otter operations. According to the February 1976 edition of the Official Airline Guide, Houston Metro operated 22 round-trip flights every weekday at this time between Clear Lake City (CLC) and Houston Intercontinental Airport, now George Bush Intercontinental Airport, in a scheduled passenger airline shuttle operation.[21] Houston Metro had agreements in place for connecting passenger feed services with Continental Airlines and Eastern Air Lines at Houston Intercontinental, with this major airport having a dedicated STOL landing area at the time specifically for Twin Otter flight operations. The Clear Lake City STOLport is no longer in existence.

The Walt Disney World resort in Florida was also served with scheduled airline flights operated with Twin Otter aircraft. The Walt Disney World Airport, also known as the Lake Buena Vista STOLport, was a private airfield constructed by The Walt Disney Company with Twin Otter operations in mind. In the early 1970s, Shawnee Airlines operated scheduled Twin Otter flights between the Disney resort and nearby Orlando Jetport, now Orlando International Airport, as well as to Tampa International Airport. This service by Shawnee Airlines is mentioned in the "Air Commuter Section" of the 6 September 1972 Eastern Air Lines system timetable as a connecting service to and from Eastern flights.[22] This STOL airfield is no longer in use.

Another commuter airline in the United States, Rocky Mountain Airways, operated Twin Otters from the Lake County Airport in Leadville, Colorado. At an elevation of 3,026 m (9,927 ft) above mean sea level, this airport is the highest airfield in the United States ever to have received scheduled passenger airline service, thus demonstrating the wide-ranging flight capabilities of the Twin Otter. Rocky Mountain Airways went on to become the worldwide launch customer for the larger, four-engine de Havilland Canada Dash 7 STOL turboprop, but continued to operate the Twin Otter, as well.

Larger scheduled passenger airlines based in the United States, Canada, Mexico, the Caribbean and Australia, particularly jetliner operators, also flew Twin Otters, with the aircraft providing connecting feeder service for these airlines. Jet aircraft operators which also flew the Twin Otter included Aeronaves de Mexico, Air BC, Alaska Airlines, ALM Antillean Airlines, Ansett Airlines, Cayman Airways, Frontier Airlines, LIAT, Norcanair, Nordair, Ozark Air Lines, Pacific Western Airlines, Quebecair, South Pacific Island Airways, Time Air, Transair, Trans Australia Airlines (TAA), Wardair and Wien Air Alaska.[23][24] In many cases, the excellent operating economics of the Twin Otter allowed airlines large and small to provide scheduled passenger flights to communities that most likely would otherwise never have received air service.

Twin Otters are also a staple of Antarctic transportation.[25] Four Twin Otters are employed by the British Antarctic Survey on research and supply flights, and several are employed by the United States Antarctic Program via contract with Kenn Borek Air. On 24–25 April 2001, two Twin Otters performed the first winter flight to Amundsen–Scott South Pole Station to perform a medical evacuation.[26][27][28][29]

On 21–22 June 2016, Kenn Borek Air's Twin Otters performed the third winter evacuation flight to Amundsen–Scott South Pole Station to remove two people for medical reasons.[30]

The Argentine Air Force has used the Twin Otter in Antarctica[31] since the 1970s, with at least one of them deployed year-round at Marambio Base.[32] The Chilean Air Force has operated the type since 1980, usually having an example based at Presidente Frei Antarctic base of the South Shetland Islands.

Alfredo Stroessner, Paraguayan head of state from 1954 until 1989, used a Twin Otter as a presidential aircraft; although the Twin Otter remained in the Paraguayan Air Force inventory after he was deposed, subsequent presidents switched to other, private aircraft for official duties.[33]

An Air Greenland Twin Otter at Kangerlussuaq Airport

As of August 2006, a total of 584 Twin Otter aircraft (all variants) remained in service worldwide. Major operators at the time included: Libyan Arab Airlines, Maldivian Air Taxi, Trans Maldivian Airways, Kenn Borek Air, and Grand Canyon Scenic Airlines. Some 115 airlines operated smaller numbers of the aircraft including Yeti Airlines in Nepal, Malaysia Airlines (which used the Twin Otter exclusively for passenger and freight transportation to the Kelabit Highlands region in Sarawak), and in the United Kingdom, the Scottish airline, Loganair which uses the aircraft to service the island of Barra in the Outer Hebrides. This daily scheduled service is unique as the aircraft lands on the beach and the schedule is partly influenced by the tide tables. Trials at Barra Airport with heavier planes than the Twin Otter, like the Short 360, failed because they sank in the sand. The Twin Otter is also used for landing at Juancho E. Yrausquin Airport, the world's shortest commercial runway, on the Caribbean island of Saba, Netherlands Antilles.

The Twin Otter has been popular with commercial skydiving operations. It can carry up to 22 skydivers to over 5,200 m (17,000 ft) (a large load compared to most other aircraft in the industry); presently, the Twin Otter is used in skydiving operations in many countries. The United States Air Force operates three Twin Otters for the United States Air Force Academy's skydiving team.

On 26 April 2001, the first ever air rescue during polar winter from the South Pole occurred with a ski-equipped Twin Otter operated by Kenn Borek Air.[34][35][36]

On 25 September 2008, the Series 400 Technology Demonstrator achieved "power on" status in advance of an official rollout.[37][38] The first flight of the Series 400 technical demonstrator, C-FDHT, took place 1 October 2008, at Victoria International Airport.[39][40]

Two days later, the aircraft departed Victoria, British Columbia for a ferry flight to Orlando, Florida, site of the 2008 National Business Aviation Association (NBAA) Conference and exhibition. The first new build Series 400 Twin Otter (SN 845) made its first flight on 16 February 2010, in Calgary, Alberta.[41] Transport Canada presented Viking Air Limited with an amended DHC-6 Type Certificate including the Series 400 on 21 July 2010.[12] Six years after, in July 2016, 100 series 400 have been delivered to 34 customers operating in 29 countries.[42]

In June 2017, 125 have been made since restarting production in 2010.[43]

Variants

[edit]
Air Seychelles de Havilland Canada DHC-6-300 Twin Otter on Bird Island, Seychelles
A Seaborne Airlines DHC-6-300 fitted with floats makes a water landing at Saint Thomas, U.S. Virgin Islands
DHC-6 Series 100
Twin-engine STOL utility transport aircraft, powered by two 550 shp (410 kW) Pratt & Whitney PT6A-20 turboprop engines.
DHC-6 Series 110
Variant of the Series 100 built to conform to BCAR (British Civil Air Regulations).
DHC-6 Series 200
Improved version.
DHC-6 Series 300
Twin-engine STOL utility transport aircraft, powered by two 680 shp (510 kW) (715 ESHP) Pratt & Whitney Canada PT6A-27 turboprop engines.
DHC-6 Series 300M
Multi-role military transport aircraft. Two of these were produced as "proof-of-concept" demonstrators. Both have since been reverted to Series 300 conformity.
DHC-6 Series 310
Variant of the Series 300 built to conform to BCAR (British Civil Air Regulations).
DHC-6 Series 320
Variant of the Series 300 built to conform to Australian Civil Air Regulations.
DHC-6 Series 300S
Six demonstrator aircraft fitted with eleven seats, wing spoilers and an anti-skid braking system. All have since been reverted to Series 300 conformity.
Viking Air DHC-6 Series 400
Viking Air production, first delivered in July 2010, powered by two Pratt & Whitney Canada PT6A-34 engines, and available on standard landing gear, straight floats, amphibious floats, skis, wheel skis, or intermediate flotation landing gear ("tundra tires").
Viking Air DHC-6 Series 400S Seaplane - never produced
Viking Air seventeen-seat seaplane version of the Series 400 with twin floats and corrosion-resistance measures for the airframe, engines and fuels system. Customer deliveries planned from early 2017.[44] 500 lb (230 kg) lighter than the 400.[45]
DHC-6 Classic 300-G
Updated DHC-6 Series 400, with an all-new interior and new flight deck featuring a glass cockpit.[46]
CC-138
Twin-engine STOL utility transport, search and rescue aircraft for the Canadian Armed Forces Search and Rescue operations. Based on the Series 300 aircraft.
UV-18A
Twin-engine STOL utility transport aircraft for the Alaska National Guard. Six built. It has been replaced by the Short C-23 Sherpa in United States Army service. In 2019 the United States Naval Research Laboratory added a UV-18A to the Scientific Development Squadron One (VXS-1) inventory.[47]
UV-18B
Parachute training aircraft for the United States Air Force Academy. The United States Air Force Academy's 98th Flying Training Squadron maintains three[48] UV-18s in its inventory as free-fall parachuting training aircraft,[49] and by the Academy Parachute Team, the Wings of Blue, for year-round parachuting operations. Based on the Series 300 aircraft.
UV-18C
United States Army designation for three Viking Air Series 400s delivered in 2013.[50]

Operators

[edit]
Main article: List of de Havilland Canada DHC-6 Twin Otter operators

In 2016, there were 281 Twin Otters in airline service with 26 new aircraft on order: 112 in North/South America, 106 in Asia Pacific and Middle East (16 orders), 38 in Europe (10 orders) and 25 in Africa.[51]

In 2018, a total of 270 Twin Otters were in airline service, and 14 on order: 111 in North/South America, 117 in the Asia Pacific and Middle East (14 orders), 26 in Europe and 13 in Africa.[52]

In 2020, there were a total of 315 Twin Otters worldwide with 220 in service, 95 in storage and 8 on order. By region there were 22 in Africa, 142 in Asia Pacific (8 orders), 37 in Europe, 4 in the Middle East and 110 in the Americas.[53]

The Twin Otter has been popular not only with bush operators as a replacement for the single-engine de Havilland Canada DHC-3 Otter but also with other civil and military customers, with over 890 aircraft built. Many commuter airlines in the United States got their start by flying the Twin Otter in scheduled passenger operations.

Airlines with six aircraft or more (2020)[53]
Operator Total In service Storage Country
Trans Maldivian Airways 56 21 35 Maldives
Kenn Borek Air 15 11 4 Canada
Grand Canyon Airlines 13 6 7 United States
Maldivian 11 10 1 Maldives
Transwest Air 9 9 0 Canada
Zimex Aviation 9 7 2 Switzerland
AeroGeo 8 0 8 Russia
Air Borealis (PAL Airlines) 8 8 0 Canada
Air Adelphi 7 6 1 Saint Vincent and the Grenadines
Air Inuit 7 7 0 Canada
LADE 7 5 2 Argentina
AIRFAST Indonesia 6 6 0 Indonesia
Aviastar Mandiri 6 5 1 Indonesia
Manta Air 6 5 1 Maldives
MASwings 6 2 4 Malaysia
Merpati 6 0 6 Indonesia
Air Tuvalu 1 0 1 Tuvalu

Accidents and incidents

[edit]
Accidents with fatalities[54]
Date Flight Fat. Location Country Event Surv.
23 November 1968 Cable Commuter Airlines 9 Santa Ana,
California		 United States While landing, impacted light pole in fog, 1.8 mi (2.9 km) short of John Wayne Airport.[55]
29 June 1972 Air Wisconsin Flight 671 5 Lake Winnebago,
Wisconsin		 United States Collided mid-air with a North Central Airlines Convair 580 carrying five, killing all.[56]
5 January 1975 Argentine Army Aviation 13 Tucumán Province Argentina Crashed due to bad weather and lack of a flight plan.[57]
9 January 1975 Golden West Airlines Flight 261 12 Whittier,
California		 United States Collided with a Cessna 150, also killing its two occupants
3 May 1976 Demonstration 11 Monze Air Force Base,
Monze		 Zambia Crashed on take off[58]
12 December 1976 Allegheny Commuter Flight 977 3 Cape May Airport,
Erma, New Jersey		 United States Crashed short of the runway
18 January 1978 Frontier Airlines 3 Pueblo, Colorado United States Crashed during a training flight[59]
2 September 1978 Airwest Airlines 11 Coal Harbour,
Vancouver,
British Columbia		 Canada Approach loss of control after a corroded rod failed and a flap retracted[60] 2
18 November 1978 Jonestown cult rescue Port Kaituma Guyana Attacked by cultists while rescuing people; aircraft managed to successfully escape. Another aircraft did not leave and the occupants were shot dead[61][62]
4 December 1978 Rocky Mountain Airways Flight 217 2 Buffalo Pass,
Colorado		 United States Survivable impact on snow, severe icing and mountain-wave downdraft[63]
30 May 1979 Downeast Airlines Flight 46 17 Rockland,
Maine		 United States Departed from Boston, crashed 1.2 mi (1.9 km) away from Knox County Regional Airport 1
24 July 1981 Air Madagascar Flight 112 19 Maroantsetra Madagascar Controlled flight into terrain (CFIT) into a mountain in cloudy conditions[64]
31 July 1981 Panamanian Air Force FAP-205 7 Coclé Province Panama Killed President Omar Torrijos,[65] cause disputed
21 February 1982 Pilgrim Airlines Flight 458 1 Scituate Reservoir
Rhode Island		 United States Emergency landing after a fire broke out on board[66] 10
11 March 1982 Widerøe Flight 933 15 Barents Sea near Gamvik Norway A mechanical fault in the elevator control system caused the pilots to lose control of pitch
18 June 1986 Grand Canyon Airlines Flight 6 20 Grand Canyon,
Arizona		 United States Collided with a Helitech Bell 206, also killing its five occupants
4 August 1986 LIAT Flight 319 13 St. Vincent St. Vincent and the Grenadines Crashed into the Caribbean Sea. The aircraft was en route between St. Lucia and St. Vincent when it crashed due to poor weather conditions, while on approach.
28 October 1989 Aloha Island Air Flight 1712 20 Molokai,
Hawaii		 United States Crashed into a mountain on approach to Molokai Airport.[67]
12 April 1990 Widerøe Flight 839 5 outside Værøy Norway Crashed in the ocean due to wind
22 April 1992 Perris Valley Aviation 16 Perris Valley Airport,
Perris, California		 United States Fuel contamination, lost power and crashed near the runway end[68] 6
27 October 1993 Widerøe Flight 744 6 east of Namsos Norway Controlled flight into terrain into forest on a hill during approach at night in bad weather 13
17 December 1994 Mission Aviation Fellowship 28 Papua New Guinea Crashed en route,[69] striking a mountain at 6,400 ft (2,000 m).[70]
10 January 1995 Merpati Nusantara Airlines Flight 6715 14 Molo Strait Indonesia Disappeared in bad weather from Sultan Muhammad Salahudin Airport to Frans Sales Lega Airport, Ruteng.[71]
30 November 1996 ACES Colombia Flight 148 15 near Medellín Colombia Crashed 8 km (5.0 mi) from Olaya Herrera Airport[72]
7 January 1997 Polynesian Airlines Flight 211 3 Mount Vaea Samoa Controlled flight into terrain in bad weather while diverting to Faleolo International Airport from Pago Pago to Apia 2
24 March 2001 Air Caraïbes Flight 1501 19 Saint Barthélemy French West Indies Crashed near Gustaf III Airport, killing one on ground.[73]
26 May 2006 Air São Tomé and Príncipe training flight 4 Ana Chaves Bay,
São Tomé Island		 São Tomé and Príncipe Airline's sole aircraft, registered S9-BAL, crashed during training flight.[74]
9 August 2007 Air Moorea Flight 1121 20 Mo'orea French Polynesia Bound for Tahiti, crashed shortly after takeoff near Moorea Airport[75]
6 May 2007 French Air and Space Force 9 Sinai Peninsula Egypt Crashed while supporting the Multinational Force and Observers[76]
8 October 2008 Yeti Airlines Flight 101 18 Lukla Nepal Destroyed on landing at Tenzing-Hillary Airport[77] 1
2 August 2009 Merpati Nusantara Airlines Flight 9760D 16 near Oksibil Indonesia Crashed about 22 km (14 mi) north of Oksibil.[78]
11 August 2009 Airlines PNG Flight 4684 13 Kokoda Valley Papua New Guinea Crashed on a mountain whilst en route from Port Moresby to Kokoda.[79]
15 December 2010 2010 Tara Air Twin Otter crash 22 Bilandu Forest Nepal A Tara Air Twin Otter crashed after take-off on a domestic flight from Lamidanda to Kathmandu, Nepal[80]
20 January 2011 Ecuadorian Air Force 6 El Capricho Ecuador En route from Río Amazonas Airport to Mayor Galo de la Torre Airport[81]
22 September 2011 Arctic Sunwest Charters 2 Yellowknife,
Northwest Territories		 Canada Float plane crashed in the street, injuring seven.[82]
23 January 2013 Kenn Borek Air 3 Mount Elizabeth Antarctica Skiplane lost en route from the South Pole to Terra Nova Bay.[83][84][85][86]
10 October 2013 MASwings Flight 3002 2 Kudat Malaysia Crashed on landing at Kudat Airport[87] 14
16 February 2014 Nepal Airlines Flight 183 18 Arghakhanchi District Nepal En route to Jumla from Pokhara.[88]
20 September 2014 Hevilift 4 near Port Moresby Papua New Guinea Crashed on landing[89] 5
24 February 2016 Tara Air Flight 193 23 Pokhara Nepal Tara Air crashed after takeoff[90]
2 October 2015 Aviastar Flight 7503 10 Luwu Regency Indonesia Aviastar pilot deviated from his route to Makassar
30 August 2018 Ethiopian Air Force 18 near Mojo Ethiopia From Dire Dawa, crashed at a place called Nannawa[91]
18 September 2019 PT Carpediem Aviasi Mandiri 4 Papua Indonesia From Timika, crashed at Hoeya district[92]
29 May 2022 Tara Air Flight 197 22 Mustang District Nepal Crashed after takeoff from Pokhara Airport
20 May 2023 [not listed] 2 Half Moon Bay, CA United States Crashed into Half Moon Bay, California
27 December 2023 Air Tindi Flight 0 Northwest Territories Canada Crashed 300 km NE of Yellowknife[93]

Specifications

[edit]
de Havilland Canada DHC-6 Twin Otter 3-view drawing
Series 100[94] 300[94] 400[95]
Cockpit crew 1–2
Seating 20 19
Length 49 ft 6 in (15.09m) 51 ft 9 in (15.77 m)
Height 19 ft 6 in / 5.94 m
Wing 65 ft 0 in (19.81 m) span, 420 sq ft (39 m2) area (10.05 AR)
Empty weight 5,850l lb / 2,653 kg 7,415  lb / 3,363 kg 7,100 lb / 3,221 kg (no accommodation)
MTOW 10,500 lb / 4763 kg 12,500 lb / 5,670 kg[a]
Payload 975 kg (2150 lb) over 1344 km (727 nm) 1135 kg (2500 lb) over 1297 km (700 nm)
860 kg (1900 lb) over 1705 km (920 nm)[b] 		1842 kg (4061 lb) over 185 km (100 nm)
1375 kg (3031 lb) over 741 km (400 nm)
Fuel capacity 378 US gal / 1466 L,[b] 2,590 lb / 1,175 kg
Turboprops (×2) P&WC PT6A-20 PT6A-27 PT6A-34
Unit Power 431 kW / 578shp 460 kW / 620shp 559 kW (750 hp)
Max. Cruise 297 km/h / 160kn 338 km/h / 182kn 337 km/h (182 kn) (FL100)
Takeoff to 50 ft STOL 1,200 ft / 366 m; CTOL 1,490 ft / 454 m; [96]
Landing from 50 ft STOL 1,050 ft / 320 m; CTOL 1,510 ft / 460 m; [96]
Stall Speed 65 mph
Ferry Range 771 nmi / 1,427 km 799 nmi / 1480 km[c]
Endurance 6.94 h[c]
Ceiling 25,000 ft / 7,620 m
Climb rate 1,600 ft/min (8.1 m/s)
FL100 fuel burn
146 kn (270 km/h) 		468.2 lb (212.4 kg)/hour
0.311 nmi/lb (1.27 km/kg)
Power/mass 0.11 hp/lb (0.18 kW/kg) 0.1 hp/lb (0.16 kW/kg) 0.12 hp/lb (0.20 kW/kg)

Table notes

[edit]
  1. ^ military -400: 14,000 lb / 6350 kg
  2. ^ a b 89 US Gal / 336 L optional wingtip tank for 3,190 lb 1,447 kg of fuel
  3. ^ a b 989 nmi / 1832 km ferry range or 8.76 h of endurance with optional wingtip tanks

See also

[edit]

Related development

Aircraft of comparable role, configuration, and era

References

[edit]

Notes

[edit]
  1. ^ "Viking restarts Twin Otter production". flightglobal.com. 2 April 2007. Retrieved 25 January 2015.
  2. ^ Mike Ody; Erik Johannesson; Ian Macintosh; Neil Aird (August 2019). "Twin Otter Archive".
  3. ^ Power – The Pratt & Whitney Canada Story, Kenneth H. Sullivan and Larry Milberry, CANAV Books 1989, ISBN 0-921022-01-8, p.146
  4. ^ "De havilland | 1963 | 0071 | Flight Archive".
  5. ^ "Airliner price index". Flight International. 10 August 1972. p. 183.
  6. ^ Aircraft Value News (26 November 2018). "Dash8-400 Values Face Some Uncertainty as Viking Takes Over".
  7. ^ "UV-18A Twin Otter - Military Aircraft". man.fas.org. Retrieved 1 November 2023.
  8. ^ a b Hemmerdinger, Jon. "De Havilland resumes Twin Otter 300 production with new variant". Flight Global. Retrieved 1 November 2023.
  9. ^ "Viking Acquires De Havilland Type Certificates." Archived 24 August 2006 at the Wayback Machine aiabc.com, 24 February 2006. Retrieved: 15 May 2010.
  10. ^ "Viking restarts Twin Otter production." flightglobal.com, 2 April 2007. Retrieved: 15 May 2010.
  11. ^ Sarsfield, Kate. "Viking Twin Otter Series 400 certification approaches." Flightglobal, 3 February 2010. Retrieved: 15 May 2010.
  12. ^ a b "News releases." Archived 8 September 2010 at the Wayback Machine Viking Air. Retrieved: 15 May 2010.
  13. ^ "Twin Otter – Zimex Aviation." Archived 1 May 2008 at the Wayback Machine zimex.ch. Retrieved: 15 May 2010.
  14. ^ Jang, Brent (14 May 2010). "The rebirth of a Canadian icon". The Globe and Mail. Retrieved 8 August 2012.
  15. ^ "Viking Air Slashes Twin Otter Production, Lays Off 116". Aviation International News. Retrieved 3 July 2015.
  16. ^ Phelps, Mark. "Updated Twin Otter Takes Off." Archived 24 October 2008 at the Wayback Machine flyingmag.com, 16 October 2008. Retrieved: 15 May 2010.
  17. ^ "100th Viking Production Series 400 Twin Otter on Display at EAA Airventure 2017" (Press release). Viking Air. 21 July 2017. Archived from the original on 28 July 2017.
  18. ^ Ballah, Brett (28 August 2019). "De Havilland owner believes renewed focus will increase Dash 8 market share". Western Aviation News. Archived from the original on 19 December 2019. Retrieved 19 December 2019.
  19. ^ Hemmerdinger, Jon (19 July 2022). "De Havilland reviewing Twin Otter and Dash 8 programmes, considering updates". Flight Global.
  20. ^ "Purchase planning handbook – turboprops table". Business & Commercial Aviation. Second Quarter 2023.
  21. ^ North American Official Airline Guide (OAG), February 1976 edition
  22. ^ "index". Departedflights.com. 14 April 2017. Retrieved 26 April 2017.
  23. ^ [1] airline system timetables
  24. ^ [2] airline system timetables & OAG flight guides
  25. ^ "NSF PR 01-29 — Civilian Aircraft to Evacuate South Pole Patient" nsf.gov. Retrieved: 15 May 2010.
  26. ^ "2001—Doctor Evacuated from the South Pole." Archived 15 March 2006 at archive.today www.70south.com. Retrieved: 15 May 2010.
  27. ^ Williams, Jeff. "Pilot says pole flight wasn't his most challenging." usatoday.com.
  28. ^ "Pilots return after historic South Pole rescue."cbc.ca/news. Retrieved: 15 May 2010. Archived 18 October 2007 at the Wayback Machine
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Bibliography

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  • Harding, Stephen (November–December 1999). "Canadian Connection: US Army Aviation's Penchant for Canadian Types". Air Enthusiast (84): 72–74. ISSN 0143-5450.
  • Hotson, Fred W. The de Havilland Canada Story. Toronto: CANAV Books, 1983. ISBN 0-07-549483-3.
  • Rossiter, Sean. Otter & Twin Otter: The Universal Airplanes. Vancouver: Douglas & McIntyre, 1998. ISBN 1-55054-637-6.
[edit]
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