View source for De Havilland Canada DHC-6 Twin Otter

{{Short description|Utility transport aircraft family by de Havilland Canada}}
{{lowercase title|de Havilland Canada DHC-6 Twin 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. Built by De Havilland Canada from 1965 to 1988, [[Viking Air]] purchased the [[type certificate]] and 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 (aeronautics)|climb]] have made it a successful [[commuter airline]]r, 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==
[[File:De Havilland Canada DHC-6-200 Twin Otter, Fayard Enterprises AN1275854.jpg|left|thumb|DHC-6-200 cockpit]]

Development of the aircraft began in 1964, with the first flight on 20 May 1965. A twin-engine replacement for the single-engine [[de Havilland Canada DHC-3 Otter|DHC-3 Otter]] retaining the DHC-3's [[STOL]] qualities, its design features included double-slotted trailing-edge [[Flap (aeronautics)|flaps]] and [[aileron]]s that work in unison with the flaps to boost STOL performance. The availability of the {{convert|550|shp|lk=in}} [[Pratt & Whitney Canada PT6|Pratt & Whitney Canada PT6A-20]] turboprop in the early 1960s made the concept of a twin feasible. A DHC-3 Otter with its [[Reciprocating engine|piston engine]] replaced with two PT6A-4 engines had already flown in 1963. It had been extensively modified for STOL research. 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.
[[File:Vancouver to Victoria. West Coast Air De Havilland DHC-6 Twin Otter floatplane -2.jpg|thumb|The floatplane version of the DHC-6 enables water landings]]
[[File:De Havilland Canada DHC-6-300 Twin Otter, WinAir AN2097069.jpg|thumb|DHC-6-300 passenger cabin]]
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 {{cvt|550|shp}} 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 {{cvt|680|hp}} engine that was [[flat rated]] to {{cvt|620|hp}} 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,
In 1976, a new -300 would have cost $700,000 and is still worth more than $2.5 million in 2018 despite the -400 introduction, many years after the -300 production ceased. 844 had been produced by the time the first production end run ended in 1988.

===New production===

After Series 300 production ended, the remaining tooling was purchased by [[Viking Air]] of [[Victoria, British Columbia]], which manufactures replacement parts for out-of-production de Havilland Canada aircraft. On 24 February 2006, Viking purchased the [[type certificate]]s from [[Bombardier Aviation]] for all out-of-production de Havilland Canada aircraft ([[de Havilland Canada DHC-1 Chipmunk|DHC-1]] through [[de Havilland Canada Dash 7|DHC-7]]). 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. As of November 2007, 40 firm orders and 10 options had been taken and a new final assembly plant was established in [[Calgary]], [[Alberta]]. [[Zimex Aviation]] of Switzerland received the first new production aircraft, serial number 845, in July 2010. 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. On 17 June 2015, Viking announced a partnership with a Chinese firm, [[Reignwood Group|Reignwood Aviation Group]]; the group would purchase 50 aircraft and become the exclusive supplier of new Series 400 Twin Otters in China.
[[File:First Flight Twin Otter Series 400 C-FDHT (cropped).jpg|thumb|First flight of the Series 400 technical demonstrator by [[Viking Air]] at [[Victoria International Airport|Victoria Airport]], 1 October 2008]]
Major changes introduced with the Series 400 include [[Honeywell Primus]] Apex fully integrated [[avionics]], deletion of the AC electrical system, modernization of the electrical and lighting systems, and use of composites for non load-bearing structures such as doors.

The 100th Series 400 Twin Otter (MSN 944) was displayed at the July 2017 [[EAA AirVenture Oshkosh]]. At the time 38% were operated as [[regional airliner]]s, 31% were in [[military aviation]] use, 26% in industrial support and 5% were in private [[air charter]]. Seventy were on regular [[landing gear]] wheels, 18 were configured as straight or amphibious [[floatplane]]s, 10 had [[tundra tire]]s and two had wheel [[ski]]s.

In 2019, Viking started making plastic components for the Twin Otter by [[3D printing|3D printer]] to help reduce cost.
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".
In 2023, its equipped price was $7.25M.

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

==Operational history==
[[File:Aerovías DAP-TWIN otter (cropped).jpg|thumb|[[Aerovías DAP]] DHC-6 Series 300 at [[Puerto Williams]], Chile]]
[[File:This is a perfectly normal approach for a Twin Otter.jpg|thumb|A Twin Otter making a normal landing approach in [[Queensland]], Australia]]
[[File:TMA DHC-6 Twin Otter at Velana International Airport, May 2017.jpg|thumb|A [[Trans Maldivian Airways]] Twin Otter at [[Velana International Airport, Maldives]]]]
[[File:Maldivian DHC-6 Twin Otter water landing.webm|thumbnail|Maldivian DHC-6 Twin Otter water landing]]
[[File:Twin Otter 4 1997-08-02.jpg|thumb|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 tire]]s.]]
[[File:Plane arrival at Barra Airport.jpg|thumb|Twin Otter daily scheduled service between Glasgow (Scotland) and [[Barra Airport (Scotland)|Barra Airport]]'s sandy beach runway]]

Twin Otters could be delivered directly from the factory with [[Float (nautical)|floats]], [[ski]]s, or [[tricycle landing gear]] fittings, making them adaptable [[bush plane]]s 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.

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 (Greater Houston)|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 ''[[OAG (company)|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. 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. 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 (Colorado)|Lake County Airport]] in [[Leadville, Colorado]]. At an elevation of {{cvt|9,927|ft|order=flip}} 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 [[Aeroméxico|Aeronaves de Mexico]], [[Air BC]], [[Alaska Airlines]], [[ALM Antillean Airlines]], [[Ansett Australia|Ansett Airlines]], [[Cayman Airways]], [[Frontier Airlines (1950–1986)|Frontier Airlines]], [[LIAT]], [[Norcanair]], [[Nordair]], [[Ozark Air Lines]], [[Pacific Western Airlines]], [[Quebecair]], [[South Pacific Island Airways]], [[Time Air]], [[Transair (Canada)|Transair]], [[Trans Australia Airlines]] (TAA), [[Wardair]] and [[Wien Air Alaska]]. 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 [[Antarctica|Antarctic]] transportation. 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.

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.

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

[[File:Kangerlussuaq-airport-air-greenland-dhc6.jpg|thumb|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 Airlines|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 (island)|Saba]], [[Netherlands Antilles]].

The Twin Otter has been popular with commercial skydiving operations. It can carry up to 22 skydivers to over {{cvt|17,000|ft|order=flip}} (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]].

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

Two days later, the aircraft departed [[Victoria, British Columbia]] for a [[Ferry flying|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]]. [[Transport Canada]] presented Viking Air Limited with an amended DHC-6 Type Certificate including the Series 400 on 21 July 2010. Six years after, in July 2016, 100 series 400 have been delivered to 34 customers operating in 29 countries.

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

==Variants==
[[File:De Havilland Canada DHC-6-100 Twin Otter (N24HV, cn 109) (2-3-2024).jpg|thumb|Short-nosed DHC-6-100 Twin Otter at [[DeLand Municipal Airport]]]]
[[File:DHC-300 Twin Otter 300 Air Seychelles.jpg|thumb|[[Air Seychelles]] de Havilland Canada DHC-6-300 Twin Otter on [[Bird Island, Seychelles]]]]
[[File:SeaborneTwinOtterSTT.jpg|thumb|A [[Seaborne Airlines]] DHC-6-300 fitted with floats makes a water landing at [[Saint Thomas, U.S. Virgin Islands]]]]

;{{visible anchor|DHC-6 Series 100}} : Twin-engine STOL utility transport aircraft, powered by two {{cvt|550|shp}} [[Pratt & Whitney Canada PT6|Pratt & Whitney PT6A-20]] turboprop engines.
;DHC-6 Series 110 : Variant of the Series 100 built to conform to BCAR (British Civil Air Regulations).
;{{Visible anchor|DHC-6 Series 200}} : Improved version.
;{{visible anchor|DHC-6 Series 300}} : Twin-engine STOL utility transport aircraft, powered by two {{cvt|680|shp}} (715 ESHP) [[Pratt & Whitney Canada]] PT6A-27 turboprop engines.
;DHC-6 Series 300M : Multi-role [[Military supply-chain management|military transport]] aircraft. Two of these were produced as "proof-of-concept" demonstrators. Both have since been reverted to Series 300 conformity.
;{{visible anchor|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.
;{{visible anchor|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 tire]]s").
;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. {{cvt|500|lb|kg}} lighter than the 400.
;DHC-6 Classic 300-G : Updated DHC-6 Series 400, with an all-new interior and new flight deck featuring a glass cockpit.
;{{visible anchor|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 Department of Military and Veterans Affairs#Alaska National Guard|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.
;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 UV-18s in its inventory as free-fall parachuting training aircraft, 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.

==Operators==
{{Main|List of de Havilland Canada DHC-6 Twin Otter operators}}
[[File:Landing beach side, flying into St Barths, Oct 2014 (15531536397).jpg|thumb|DHC-6 Cockpit view landing at St Barths]]
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.

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.

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.

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.

{| class="wikitable sortable" style="margin: 1em auto;"
|+Airlines with six aircraft or more (2020)
! scope="col" width="140" | Operator
! scope="col" width="2" | Total
! scope="col" width=''2" | In service
! scope="col" width="2" | Stored
! scope="col" width="125" | Country
|-
| [[Trans Maldivian Airways]] || 84 || 75 || 9 ||{{flaglist|Maldives}}
|-
| [[Kenn Borek Air]] || 15 || 11 || 4 || {{flaglist|Canada}}
|-
| [[Grand Canyon Airlines]] || 13 || 6 || 7 || {{flaglist|United States}}
|-
| [[Maldivian (airline)|Maldivian]] || 11 || 10 || 1 || {{flaglist|Maldives}}
|-
| [[Transwest Air]] || 9 || 9 || 0 ||{{flaglist|Canada}}
|-
| [[Zimex Aviation]] || 9 || 7 || 2 || {{flaglist|Switzerland}}
|-
| [[AeroGeo]]|| 8 || 0 || 8 || {{flaglist|Russia}}
|-
| [[PAL Airlines|Air Borealis]] (PAL Airlines) || 8 || 8 || 0 ||{{flaglist|Canada}}
|-
| [[Air Adelphi]]|| 7 || 6 || 1 || {{flaglist|Saint Vincent and the Grenadines|table=yes}}
|-
| [[Air Inuit]] || 7 || 7 || 0 ||{{flaglist|Canada}}
|-
| [[LADE]] || 7 || 5 || 2 || {{flaglist|Argentina}}
|-
| [[Airfast Indonesia]]|| 6 || 6 || 0 || {{flaglist|Indonesia}}
|-
| [[Aviastar (Indonesia)|Aviastar Mandiri]] || 6 || 5 || 1 || {{flaglist|Indonesia}}
|-
| [[Manta Air]] || 6 || 5 || 1 ||{{flaglist|Maldives}}
|-
| [[MASwings]] || 6 || 2 || 4 ||{{flaglist|Malaysia}}
|-
| [[Merpati Nusantara Airlines|Merpati]] || 6 || 0 || 6 || {{flaglist|Indonesia}}
|}

==Accidents and incidents==

{| class="wikitable sortable" style="margin: 1em auto;"
|+ Accidents with fatalities
! scope="col" width="100" | Date 
! scope="col" width="170" | Flight 
! scope="col" width="2" | Fatalities
! scope="col" width="180"  | Location
! scope="col" width="35" | Country
! scope="col" width="400" class="unsortable" | Event
|-
| 23 November 1968 || [[Golden West Airlines#History|Cable Commuter Airlines]] || 9 || [[Santa Ana, California|Santa Ana]], California || United States || While landing, impacted light pole in fog, {{cvt|1.8|mi}} short of [[John Wayne Airport]].
|-
| 29 June 1972 || [[1972 Lake Winnebago mid-air collision|Air Wisconsin Flight 671]] || 5 || [[Lake Winnebago]], Wisconsin || United States || Collided mid-air with a [[North Central Airlines]] [[Convair 580]] carrying five, killing all.
|-
| 5 January 1975 || [[Argentine Army Aviation]] || 13 || [[Tucumán Province]] || Argentina || Crashed due to bad weather and lack of a [[flight plan]].
|-
| 9 January 1975 || [[Golden West Airlines Flight 261]] || 12 || [[Whittier, California|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
|-
| 12 December 1976 || [[Allegheny Commuter Flight 977]]|| 3 || [[Cape May Airport]], New Jersey || United States || Crashed short of the runway
|-
| 18 January 1978 || [[Frontier Airlines (1950–1986)|Frontier Airlines]] || 3 || [[Pueblo, Colorado|Pueblo]], Colorado || United States || Crashed during a training flight
|-
| 2 September 1978 || [[Airwest Airlines]]|| 11 || [[Coal Harbour]], British Columbia || Canada || Approach [[Loss of control (aeronautics)|loss of control]] after a [[corrosion|corroded]] rod failed and a [[Flap (aeronautics)|flap]] retracted
|-
| 18 November 1978 || [[Jonestown]] cult rescue || || [[Port Kaituma]] || Guyana || [[Jonestown#Port Kaituma airstrip shootings|Attacked by cultists]] while rescuing people; aircraft managed to successfully escape. Another aircraft did not leave and the occupants were shot dead
|-
| 4 December 1978 || [[Rocky Mountain Airways Flight 217]] || 2 || [[Buffalo Pass (Continental Divide)|Buffalo Pass]], Colorado || United States || Survivable impact on snow, severe icing and mountain-wave downdraft
|-
| 30 May 1979 || [[Downeast Airlines Flight 46]] || 17 || [[Rockland, Maine|Rockland]], Maine || United States || Departed from Boston, crashed {{cvt|1.2|mi}} away from [[Knox County Regional Airport]]
|-
| 24 July 1981 || [[Air Madagascar]] Flight 112 || 19 || [[Maroantsetra]] || Madagascar || [[Controlled flight into terrain]] (CFIT) into a mountain in cloudy conditions
|-
| 31 July 1981 || [[1981 Panamanian Air Force Twin Otter crash|Panamanian Air Force FAP-205]] || 7 || [[Coclé Province]] || Panama || Killed President [[Omar Torrijos]], 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
|-
| 11 March 1982 || [[Widerøe Flight 933]] || 15 || [[Barents Sea]] near [[Gamvik Municipality|Gamvik]] || Norway || A mechanical fault in the [[Elevator (aeronautics)|elevator]] control system caused the pilots to lose control of [[Aircraft flight dynamics|pitch]]
|-
| 18 June 1986 || [[1986 Grand Canyon mid-air collision|Grand Canyon Airlines Flight 6]] || 20 || [[Grand Canyon]],<br>Arizona || United States || Collided with a Helitech [[Bell 206]], also killing its five occupants
|-
| 4 August 1986 || [[LIAT Flight 319]] || 13 || [[Saint Vincent (Saint Vincent and the Grenadines)|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]].
|-
| 12 April 1990 || [[Widerøe Flight 839]] || 5 || outside [[Værøy Municipality|Værøy]] || Norway || Crashed in the ocean due to wind
|-
| 22 April 1992 || [[Perris Valley Airport#Accidents and incidents|Perris Valley Aviation]] || 16 || [[Perris Valley Airport]], California || United States || Fuel contamination, lost power and crashed near the runway end
|-
| 27 October 1993 || [[Widerøe Flight 744]] || 6 || east of [[Namsos (town)|Namsos]] || Norway || [[Controlled flight into terrain]] into forest on a hill during approach at night in bad weather
|-
| 17 December 1994 || [[Mission Aviation Fellowship]] || 28 || || Papua New Guinea || Crashed en route, striking a mountain at {{cvt|6400|ft}}.
|-
| 10 January 1995 || [[Merpati Nusantara Airlines#Accidents and incidents|Merpati Nusantara Airlines Flight 6715]] || 14 || [[Savu Sea|Molo Strait]] || Indonesia || Disappeared in bad weather from [[Sultan Muhammad Salahudin Airport]] to [[Frans Sales Lega Airport]], [[Ruteng]].
|-
| 30 November 1996 || [[ACES Colombia#Accidents and incidents|ACES Colombia Flight 148]] || 15 || near [[Medellín]] || Colombia || Crashed {{cvt|8|km|abbr=on}} from [[Olaya Herrera Airport]]
|-
| 7 January 1997 || [[Samoa Airways#Accidents and incidents|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]]
|-
| 24 March 2001 || [[Air Caraïbes Flight 1501]] || 19 || [[Saint Barthélemy]] || French West Indies || Crashed near [[Gustaf III Airport]], killing one on ground.
|-
| 26 May 2006 || [[Air São Tomé and Príncipe#Incidents and accidents|Air São Tomé and Príncipe]] training flight || 4 || [[Ana Chaves Bay]], [[São Tomé Island]] || {{no wrap|São Tomé and Príncipe}} || Airline's sole aircraft, registered S9-BAL, crashed during training flight.
|-
| 9 August 2007 || [[Air Moorea Flight 1121]] || 20 || [[Mo'orea]] || French Polynesia || Bound for [[Tahiti]], crashed shortly after takeoff near [[Moorea Airport]]
|-
| 6 May 2007 || [[French Air and Space Force]] || 9 || [[Sinai Peninsula]] || Egypt || Crashed while supporting the [[Multinational Force and Observers]]
|-
| 8 October 2008 || [[Yeti Airlines Flight 101]] || 18 || [[Lukla]] || Nepal || Destroyed on landing at [[Tenzing-Hillary Airport]]
|-
| 2 August 2009 || [[Merpati Nusantara Airlines Flight 9760D]] || 16 || near [[Oksibil]] || Indonesia || Crashed about {{cvt|22|km}} north of [[Oksibil]].
|-
| 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]].
|-
| 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
|-
| 20 January 2011 || [[Ecuadorian Air Force]] || 6 || El Capricho || Ecuador || En route from [[Río Amazonas Airport]] to [[Mayor Galo de la Torre Airport]]
|-
| 22 September 2011 || [[Arctic Sunwest Charters#Accidents and incidents|Arctic Sunwest Charters]] || 2 || [[Yellowknife]], Northwest Territories || Canada || Float plane crashed in the street, injuring seven.
|-
| 23 January 2013 || [[Kenn Borek Air#Accidents and incidents|Kenn Borek Air]] || 3 || [[Mount Elizabeth (Antarctica)|Mount Elizabeth]] || Antarctica || Skiplane lost en route from the [[South Pole]] to [[Terra Nova Bay]].
|-
| 10 October 2013 || [[MASwings]] Flight 3002 || 2 || [[Kudat]] || Malaysia || Crashed on landing at [[Kudat Airport]]
|-
| 16 February 2014 || [[Nepal Airlines Flight 183]] || 18 || {{no wrap|[[Arghakhanchi District]]}} || Nepal || En route to Jumla from Pokhara.
|-
| 20 September 2014 || Hevilift || 4 || near [[Port Moresby]] || Papua New Guinea || Crashed on landing
|-
| 24 February 2016 || [[Tara Air Flight 193]] || 23 || [[Pokhara]] || Nepal || [[Tara Air]] crashed after takeoff
|-
| 2 October 2015 || [[Aviastar Flight 7503]] || 10 || [[Luwu Regency]] || Indonesia || [[Aviastar (Indonesia)|Aviastar]] pilot deviated from his route to [[Makassar]]
|-
| 30 August 2018 || [[Ethiopian Air Force]] || 18 || near [[Mojo, Ethiopia|Mojo]] || Ethiopia || From [[Dire Dawa]], crashed at a place called Nannawa
|-
| {{no wrap|18 September 2019}} || {{no wrap|[[PT Carpediem Aviasi Mandiri]]}} || 4 || [[Papua (province)|Papua]] || Indonesia || From [[Timika]], crashed at Hoeya district
|-
| 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|Half Moon Bay]], California || United States || Crashed into Half Moon Bay, California 
|-
|27 December 2023 || [[Air Tindi]] Flight  || 0 || [[Northwest Territories]] || Canada || Crashed 300&nbsp;km NE of [[Yellowknife]]
|-
| 20 October 2024 || [[SAM Air]]|| 4 || [[Pohuwato Regency]] || Indonesia || Crashed while attempting to land at [[Panua Pohuwato Airport|Panua Airport]] in Pohuwato Regency, [[Gorontalo]].
|-
|25 April 2025 || [[Royal Thai Police]]|| 6 || [[Phetchaburi Province]] || Thailand || Crashed into the sea near [[Hua Hin Airport]].
|}

==Specifications==
[[File:De Havilland Canada UV-18A Twin Otter 3-view line drawing.png|thumb|de Havilland Canada DHC-6 Twin Otter 3-view drawing]]

{| class="wikitable"
|-
! Series
! 100
! 300
! 400
|-
! Cockpit crew
| colspan=3 | 1–2
|-
! Seating
| colspan=2 | 20 || 19
|-
! Length
| 49&nbsp;ft 6 in (15.09m)
| colspan=2 | {{cvt|15.77|m|ftin|order=flip}}
|-
! Height
| colspan=3 | 19&nbsp;ft 6 in / 5.94 m
|-
! Wing
| colspan=3 | {{cvt|19.81|m|ftin|order=flip}} span, {{cvt|39|m2|sqft|order=flip}} area ({{#expr:19.8/(39/19.8)round2}} AR)
|-
! Empty weight
| 5,850l&nbsp;[[pound (mass)|lb]] / 2,653&nbsp;kg || 7,415&nbsp; lb / 3,363&nbsp;kg || 7,100&nbsp;lb / 3,221&nbsp;kg (no accommodation)
|-
! [[Maximum takeoff weight|MTOW]]
| 10,500&nbsp;lb / 4763&nbsp;kg 
| colspan=2 | 12,500&nbsp;lb / 5,670&nbsp;kg{{efn|military -400: 14,000 lb / 6350 kg}}
|-
! Payload
| 975&nbsp;kg (2150&nbsp;lb) over 1344&nbsp;km (727&nbsp;nm)
| 1135&nbsp;kg (2500&nbsp;lb) over 1297&nbsp;km (700&nbsp;nm)<br />860&nbsp;kg (1900&nbsp;lb) over 1705&nbsp;km (920&nbsp;nm){{efn|name=LRtank}}
| 1842&nbsp;kg (4061&nbsp;lb) over 185&nbsp;km (100&nbsp;nm)<br />1375&nbsp;kg (3031&nbsp;lb) over 741&nbsp;km (400&nbsp;nm)
|-
! Fuel capacity
| || || 378&nbsp;US gal / 1466&nbsp;L,{{efn|name=LRtank|89 US Gal / 336 L optional wingtip tank for 3,190 lb 1,447 kg of fuel}} 2,590&nbsp;lb / 1,175&nbsp;kg
|-
! Turboprops (×2)
| [[Pratt & Whitney Canada PT6|P&WC PT6]]A-20 || PT6A-27 || PT6A-34
|-
! Unit Power
| 431&nbsp;kW / 578shp || 460&nbsp;kW / 620shp || {{cvt|750|hp|kW|0|order=flip}}
|-
! Max. Cruise
| 297&nbsp;km/h / 160kn || 338&nbsp;km/h / 182kn || {{cvt|182|knots|km/h|order=flip}} (FL100)
|-
! Takeoff to 50&nbsp;ft
| || || STOL 1,200&nbsp;ft / 366 m; CTOL 1,490&nbsp;ft / 454 m;
|-
! Landing from 50&nbsp;ft
| || || STOL 1,050&nbsp;ft / 320 m; CTOL 1,510&nbsp;ft / 460 m;
|-
! Stall Speed
| 65&nbsp;mph || || 
|-
! Ferry [[Range (aircraft)|Range]]
| 771&nbsp;[[nautical mile|nmi]] / 1,427&nbsp;km || || 799&nbsp;nmi / 1480&nbsp;km{{efn|name=LRperf|989&nbsp;nmi / 1832&nbsp;km ferry range or 8.76 h of endurance with optional wingtip tanks}}
|-
! Endurance
| || || 6.94 h{{efn|name=LRperf}}
|-
! Ceiling
| colspan=3 | 25,000&nbsp;ft / 7,620&nbsp;m
|-
! Climb rate
| || colspan=2 | {{cvt|1,600|ft/min|m/s}} 
|-
! FL100 fuel burn<br />{{cvt|146|knots|km/h}}
| colspan= 2 | || {{cvt|468.2|lb}}/hour<br />{{cvt|0.311|nmi/lb|km/kg}}
|-
! Power/mass
| {{cvt|{{#expr:578*2/10500round2}}|hp/lb}} || {{cvt|{{#expr:620*2/12500round2}}|hp/lb}} || {{cvt|{{#expr:750*2/12500round2}}|hp/lb}}
|}

=== Table notes ===
{{Notelist}}

==See also==
{{Portal|Aviation|Canada}}
{{aircontent|
|related=
* [[de Havilland Canada DHC-3 Otter]]
* [[de Havilland Canada Dash 7]]
|similar aircraft=
* [[Antonov An-28]]
* [[Britten-Norman Trislander]]
* [[CASA C-212 Aviocar]]
* [[Dornier 228]]
* [[Embraer EMB 110 Bandeirante]]
* [[GAF Nomad]] N24
* [[Harbin Y-12]]
* [[IAI Arava]]
* [[Let L-410 Turbolet]]
* [[PZL M28 Skytruck]]
* [[Short SC.7 Skyvan]]
|lists=
|see also=
}}


[[Category:De Havilland Canada DHC-6 Twin Otter| ]]
[[Category:De Havilland Canada aircraft|DHC-6]]
[[Category:Viking Air aircraft|DHC-6]]
[[Category:1960s Canadian civil utility aircraft]]
[[Category:1960s Canadian military utility aircraft]]
[[Category:High-wing aircraft]]
[[Category:Articles containing video clips]]
[[Category:STOL aircraft]]
[[Category:Aircraft first flown in 1965]]
[[Category:Twin-turboprop tractor aircraft]]
[[Category:Floatplanes]]
[[Category:Aircraft with fixed tricycle landing gear]]