Wikipedia

de Havilland Canada DHC-6 Twin Otter

Thede Havilland Canada DHC-6 Twin Otteris a CanadianSTOL(Short Takeoff and Landing)utility aircraftdeveloped byde Havilland Canadain the mid-1960s and still in production today. Built by De Havilland Canada from 1965 to 1988,Viking Airpurchased thetype certificateand 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.

DHC-6 Twin Otter
WinairDHC-6 Twin Otter landing atGustaf III Airport
General information
TypeUtility aircraft
Manufacturerde Havilland Canada
Viking Air
StatusIn production[1]
Number builtDecember 2019: 994
(844 DHC, 150 Viking)[2]
History
Manufactured1965–1988 (Series 100–300)
2008–present (Series 400)
2023–present (Series 300-G)
Introduction date1966
First flight20 May 1965
Developed fromde Havilland Canada DHC-3 Otter

The aircraft's fixedtricycle undercarriage,STOL capabilities, twinturbopropengines and high rate ofclimbhave made it a successfulcommuter airliner,typically seating 18–20 passengers, as well as a cargo andmedical evacuationaircraft. In addition, the Twin Otter has been popular with commercial skydiving operations, and is used by theUnited States Army Parachute Teamand the98th Flying Training Squadronof theUnited States Air Force.

Design and development

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Aerovías DAPDHC-6 Series 300 atPuerto Williams
A Twin Otter making a normal landing approach inQueensland
First flight of the Series 400 technical demonstrator byViking AiratVictoria 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-engineDHC-3 Otterretaining the DHC-3'sSTOLqualities, its design features included double-slotted trailing-edgeflapsandaileronsthat work in unison with the flaps to boost STOL performance. The availability of the 550shaft horsepower(410 kW)Pratt & Whitney Canada PT6A-20turboprop in the early 1960s made the concept of a twin feasible. A DHC-3 Otter with itspiston enginereplaced with two PT6A-4[3]engines had already flown in 1963. It had been extensively modified for STOL research.[4]Tobush planeoperators, 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 wasflat ratedto 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 inTorontobyde Havilland Canadaended 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

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After Series 300 production ended, the remaining tooling was purchased byViking AirofVictoria, British Columbia,which manufactures replacement parts for out-of-production de Havilland Canada aircraft. On 24 February 2006, Viking purchased thetype certificatesfromBombardier Aviationfor all out-of-production de Havilland Canada aircraft (DHC-1throughDHC-7).[9]The ownership of the certificates gives Viking the exclusive right to manufacture new aircraft.

On 17 July 2006, at theFarnborough 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 inCalgary,Alberta.[11][12]Zimex Aviationof 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 announced a partnership with a Chinese firm,Reignwood Aviation Group;the group would purchase 50 aircraft and become the exclusive supplier of new Series 400 Twin Otters in China.

Major changes introduced with the Series 400 includeHoneywell PrimusApex fully integratedavionics,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.[16]

The 100th Series 400 Twin Otter (MSN 944) was displayed at the July 2017EAA AirVenture Oshkosh.At the time 38% were operated asregional airliners,31% were inmilitary aviationuse, 26% in industrial support and 5% were in privateair charter.Seventy were on regularlanding gearwheels, 18 were configured as straight or amphibiousfloatplanes,10 hadtundra tiresand two had wheelskis.[17]

In 2019, Viking started making plastic components for the Twin Otter by3D printerto help reduce cost.[18] Twin Otter production was suspended in 2019 during theCOVID-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

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ATrans Maldivian AirwaysTwin Otter atVelana International Airport
Maldivian DHC-6 Twin Otter water landing
De Havilland Canada DHC-6 Twin Otter onBeechey Islandat the graves of seamen who were part ofFranklin's lost expedition(Nunavut, Canada)circa1997. Note thetundra tires.
Twin Otter daily scheduled service between Glasgow (Scotland) andBarra Airport's sandy beach runway

Twin Otters could be delivered directly from the factory withfloats,skis,ortricycle landing gearfittings, making them adaptablebush planesfor remote and northern areas. Areas including Canada and the United States, (specificallyAlaska) had much of the demand. Many Twin Otters still serve in theArcticandsubarctic,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 asPapua 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.Widerøeof 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 toMetro Airlines) constructed their ownSTOLportairstrip with a passenger terminal and maintenance hangar inClear Lake City, Texas,near theJohnson Space Center.TheClear Lake City STOLportwas specifically designed for Twin Otter operations. According to the February 1976 edition of theOfficial Airline Guide,Houston Metro operated 22 round-trip flights every weekday at this time between Clear Lake City (CLC) and Houston Intercontinental Airport, nowGeorge Bush Intercontinental Airport,in a scheduled passenger airline shuttle operation.[21]Houston Metro had agreements in place for connecting passenger feed services withContinental AirlinesandEastern Air Linesat 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.

TheWalt Disney Worldresort in Florida was also served with scheduled airline flights operated with Twin Otter aircraft. TheWalt Disney World Airport,also known as the Lake Buena Vista STOLport, was a private airfield constructed byThe Walt Disney Companywith Twin Otter operations in mind. In the early 1970s, Shawnee Airlines operated scheduled Twin Otter flights between the Disney resort and nearby Orlando Jetport, nowOrlando International Airport,as well as toTampa International Airport.This service by Shawnee Airlines is mentioned in the "Air Commuter Section" of the 6 September 1972Eastern Air Linessystem 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 theLake County AirportinLeadville, 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-enginede Havilland Canada Dash 7STOL 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 includedAeronaves 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),WardairandWien 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 ofAntarctictransportation.[25]Four Twin Otters are employed by theBritish Antarctic Surveyon research and supply flights, and several are employed by theUnited States Antarctic Programvia contract withKenn Borek Air.On 24–25 April 2001, two Twin Otters performed the first winter flight toAmundsen–Scott South Pole Stationto 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]

TheArgentine Air Forcehas used the Twin Otter in Antarctica[31]since the 1970s, with at least one of them deployed year-round atMarambio Base.[32]TheChilean Air Forcehas operated the type since 1980, usually having an example based atPresidente Frei Antarctic baseof theSouth 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 theParaguayan Air Forceinventory after he was deposed, subsequent presidents switched to other, private aircraft for official duties.[33]

AnAir GreenlandTwin Otter atKangerlussuaq 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,andGrand Canyon Scenic Airlines.Some 115 airlines operated smaller numbers of the aircraft includingYeti Airlinesin Nepal,Malaysia Airlines(which used the Twin Otter exclusively for passenger and freight transportation to theKelabit Highlandsregion inSarawak), and in the United Kingdom, the Scottish airline,Loganairwhich uses the aircraft to service the island ofBarrain theOuter 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 atBarra Airportwith 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 atJuancho E. Yrausquin Airport,the world's shortest commercial runway, on the Caribbean island ofSaba,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. TheUnited States Air Forceoperates three Twin Otters for theUnited States Air Force Academy's skydiving team.

On 26 April 2001, the first ever air rescue during polar winter from theSouth Poleoccurred with a ski-equipped Twin Otter operated byKenn 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, atVictoria International Airport.[39][40]

Two days later, the aircraft departedVictoria, British Columbiafor aferry flighttoOrlando, Florida,site of the 2008National 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, inCalgary,Alberta.[41]Transport Canadapresented 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

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Short-nosed DHC-6-100 Twin Otter atDeLand Municipal Airport
Air Seychellesde Havilland Canada DHC-6-300 Twin Otter onBird Island, Seychelles
ASeaborne AirlinesDHC-6-300 fitted with floats makes a water landing atSaint 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-20turboprop 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 CanadaPT6A-27 turboprop engines.
DHC-6 Series 300M
Multi-rolemilitary transportaircraft. 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 Airproduction, 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-seatseaplaneversion of the Series 400 with twin floats and corrosion-resistance measures for theairframe,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 rescueaircraft for theCanadian Armed Forces Search and Rescueoperations. Based on the Series 300 aircraft.
UV-18A
Twin-engine STOL utility transport aircraft for theAlaska National Guard.Six built. It has been replaced by theShort C-23 SherpainUnited States Armyservice. In 2019 theUnited States Naval Research Laboratoryadded a UV-18A to the Scientific Development Squadron One (VXS-1) inventory.[47]
UV-18B
Parachute training aircraft for theUnited States Air Force Academy.The United States Air Force Academy's98th Flying Training Squadronmaintains 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

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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-enginede Havilland Canada DHC-3 Otterbut 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 84 75 9 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

Accidents and incidents

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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 ofJohn Wayne Airport.[55]
29 June 1972 Air Wisconsin Flight 671 5 Lake Winnebago,
Wisconsin		 United States Collided mid-air with aNorth Central AirlinesConvair 580carrying five, killing all.[56]
5 January 1975 Argentine Army Aviation 13 Tucumán Province Argentina Crashed due to bad weather and lack of aflight plan.[57]
9 January 1975 Golden West Airlines Flight 261 12 Whittier,
California		 United States Collided with aCessna 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 Approachloss of controlafter acorrodedrod failed and aflapretracted[60] 2
18 November 1978 Jonestowncult rescue Port Kaituma Guyana Attacked by cultistswhile 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 fromKnox County Regional Airport 1
24 July 1981 Air MadagascarFlight 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 PresidentOmar 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 SeanearGamvik Norway A mechanical fault in theelevatorcontrol system caused the pilots to lose control ofpitch
18 June 1986 Grand Canyon Airlines Flight 6 20 Grand Canyon,
Arizona		 United States Collided with a HelitechBell 206,also killing its five occupants
4 August 1986 LIAT Flight 319 13 St. Vincent St. Vincent and the Grenadines Crashed into theCaribbean 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 AirFlight 1712 20 Molokai,
Hawaii		 United States Crashed into a mountain on approach toMolokai Airport.[67]
12 April 1990 Widerøe Flight 839 5 outsideVærøy 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 ofNamsos Norway Controlled flight into terraininto 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 fromSultan Muhammad Salahudin AirporttoFrans Sales Lega Airport,Ruteng.[71]
30 November 1996 ACES Colombia Flight 148 15 nearMedellín Colombia Crashed 8 km (5.0 mi) fromOlaya Herrera Airport[72]
7 January 1997 Polynesian Airlines Flight 211 3 Mount Vaea Samoa Controlled flight into terrainin bad weather while diverting toFaleolo International AirportfromPago PagotoApia 2
24 March 2001 Air Caraïbes Flight 1501 19 Saint Barthélemy French West Indies Crashed nearGustaf III Airport,killing one on ground.[73]
26 May 2006 Air São Tomé and Príncipetraining 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 forTahiti,crashed shortly after takeoff nearMoorea Airport[75]
6 May 2007 French Air and Space Force 9 Sinai Peninsula Egypt Crashed while supporting theMultinational Force and Observers[76]
8 October 2008 Yeti Airlines Flight 101 18 Lukla Nepal Destroyed on landing atTenzing-Hillary Airport[77] 1
2 August 2009 Merpati Nusantara Airlines Flight 9760D 16 nearOksibil Indonesia Crashed about 22 km (14 mi) north ofOksibil.[78]
11 August 2009 Airlines PNG Flight 4684 13 Kokoda Valley Papua New Guinea Crashed on a mountain whilst en route fromPort MoresbytoKokoda.[79]
15 December 2010 2010 Tara Air Twin Otter crash 22 BilanduForest Nepal ATara AirTwin 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 fromRío Amazonas AirporttoMayor 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 theSouth PoletoTerra Nova Bay.[83][84][85][86]
10 October 2013 MASwingsFlight 3002 2 Kudat Malaysia Crashed on landing atKudat 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 nearPort Moresby Papua New Guinea Crashed on landing[89] 5
24 February 2016 Tara Air Flight 193 23 Pokhara Nepal Tara Aircrashed after takeoff[90]
2 October 2015 Aviastar Flight 7503 10 Luwu Regency Indonesia Aviastarpilot deviated from his route toMakassar
30 August 2018 Ethiopian Air Force 18 nearMojo Ethiopia FromDire Dawa,crashed at a place called Nannawa[91]
18 September 2019 PT Carpediem Aviasi Mandiri 4 Papua Indonesia FromTimika,crashed at Hoeya district[92]
29 May 2022 Tara Air Flight 197 22 Mustang District Nepal Crashed after takeoff fromPokhara Airport
20 May 2023 [not listed] 2 Half Moon Bay, CA United States Crashed into Half Moon Bay, California
27 December 2023 Air TindiFlight 0 Northwest Territories Canada Crashed 300 km NE ofYellowknife[93]
20 October 2024 SAM Air 4 Pohuwato Regency Indonesia Crashed while attempting to land atPanua Airportin Pohuwato Regency,Gorontalo.[94][95]

Specifications

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de Havilland Canada DHC-6 Twin Otter 3-view drawing
Series 100[96] 300[96] 400[97]
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 5,850llb/ 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;[98]
Landing from 50 ft STOL 1,050 ft / 320 m; CTOL 1,510 ft / 460 m;[98]
Stall Speed 65 mph
FerryRange 771nmi/ 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

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  1. ^military -400: 14,000 lb / 6350 kg
  2. ^ab89 US Gal / 336 L optional wingtip tank for 3,190 lb 1,447 kg of fuel
  3. ^ab989 nmi / 1832 km ferry range or 8.76 h of endurance with optional wingtip tanks

See also

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Related development

Aircraft of comparable role, configuration, and era

References

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Notes

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  1. ^"Viking restarts Twin Otter production".flightglobal.com.2 April 2007.Retrieved25 January2015.
  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,ISBN0-921022-01-8,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.Retrieved1 November2023.
  8. ^abHemmerdinger, Jon."De Havilland resumes Twin Otter 300 production with new variant".Flight Global.Retrieved1 November2023.
  9. ^ "Viking Acquires De Havilland Type Certificates."Archived24 August 2006 at theWayback Machineaiabc.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. ^ab"News releases."Archived8 September 2010 at theWayback MachineViking Air.Retrieved: 15 May 2010.
  13. ^ "Twin Otter – Zimex Aviation."Archived1 May 2008 at theWayback Machinezimex.ch.Retrieved: 15 May 2010.
  14. ^Jang, Brent (14 May 2010)."The rebirth of a Canadian icon".The Globe and Mail.Retrieved8 August2012.
  15. ^"Viking Air Slashes Twin Otter Production, Lays Off 116".Aviation International News.Retrieved3 July2015.
  16. ^Phelps, Mark."Updated Twin Otter Takes Off."Archived24 October 2008 at theWayback Machineflyingmag.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 fromthe originalon 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 fromthe originalon 19 December 2019.Retrieved19 December2019.
  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.Retrieved26 April2017.
  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."Archived15 March 2006 atarchive.todaywww.70south.com.Retrieved: 15 May 2010.
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Bibliography

edit
  • Harding, Stephen (November–December 1999). "Canadian Connection: US Army Aviation's Penchant for Canadian Types".Air Enthusiast(84): 72–74.ISSN0143-5450.
  • Hotson, Fred W.The de Havilland Canada Story.Toronto: CANAV Books, 1983.ISBN0-07-549483-3.
  • Rossiter, Sean.Otter & Twin Otter: The Universal Airplanes.Vancouver: Douglas & McIntyre, 1998.ISBN1-55054-637-6.
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