de Havilland Canada DHC-6 Twin Otter
| DHC-6 Twin Otter | |
|---|---|
 |
|
| A West Coast Air Twin Otter floatplane | |
| Role | utility aircraft |
| Manufacturer | de Havilland Canada Viking Air - (400 series) |
| First flight | May 20, 1965 |
| Introduced | 1966 |
| Produced | 1965–1988 2008–present |
| Number built | 845 |
| Unit cost | $2,000,000 USD[1] |
| Developed from | DHC-3 Otter |
| Developed into | de Havilland Canada Dash 7 |
The DHC-6 Twin Otter is a Canadian 20-passenger STOL (Short Takeoff and Landing) utility aircraft developed by de Havilland Canada and currently produced by Viking Air. The aircraft's fixed tricycle undercarriage, STOL abilities and high rate of climb have made it a successful cargo, regional passenger airliner and MEDEVAC aircraft. In addition, the Twin Otter has been popular with commercial skydiving operations, and it is used by the United States Army Parachute Team.
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Design and development
Development of the aircraft began in 1964, with the first flight on May 20, 1965. A twin-engined replacement for the single-engined Otter had been planned by de Havilland Canada. Twin engines not only provided improved safety but also allowed for an increase in payload while retaining the renowned STOL qualities. 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 shp (410 kW) Pratt and Whitney Canada PT6A-20 propeller turbine engine in the early 1960s made the concept of a twin more feasible. To bush operators, the improved reliability of turboprop power and the improved performance of a twin-engined configuration made it an immediately popular alternative to the single engine, 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 number 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 to 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 shaft horsepower PT6A-20 engines.
In 1969, the 300 series 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 sub-variants (Series 310 for United Kingdom operators, Series 320 for Australian operators, etc.) sold before production ended in 1988.
New production
After series production ended, the remaining tooling was purchased by Viking Air of Victoria, British Columbia, which manufacture replacement parts for all of the out of production de Havilland Canada aircraft. On February 24, 2006 Viking purchased the type certificates from Bombardier Aerospace for all the out of production de Havilland DHC-1 through DHC-7 aircraft.[2] The ownership of the certificates gives Viking the exclusive right to manufacture new aircraft.
On July 17, 2006, at the Farnborough Air Show, Viking Air announced its intention to offer a "Series 400" Twin Otter. On April 2, 2007 Viking announced that with 27 orders and options in hand, it was restarting production of the Twin Otter with a more powerful Pratt & Whitney Canada PT6A-34/35 engine.[3] As of November 2007, 40 firm orders and 10 options have been taken and a new assembly plant has been established in Calgary, Alberta with customer deliveries commencing in the second quarter of 2010.[4][5] Zimex Aviation of Switzerland will receive the first aircraft.[6][7]
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 system, and use of composites for non-load-bearing structures such as doors.[8]
- Announced orders
- Air Loyaute (2)
- Air Moorea (2)[5]
- Air Seychelles (2)[5]
- European Coastal Airlines (6)
- Global Aerospace Logistics (GAL) (10), Order placed June 16, 2009)
- Loch Ard Otters (6 plus 6 options)[5]
- Montenegro Charter Company (1)[9]
- Maldivian Air Taxi (2)
- Petro Air (1)
- Trans Maldivian Airways (5)[5]
- United States Army Parachute Team (3)[10]
- Vityaz Avia Corporation (2)
- Zimex Aviation (1)[5]
Operational history
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 including Canada and the United States, specifically Alaska. Many Twin Otters still serve in the far north, but they can also be found in Africa, Australia, Antarctica and other regions where bush planes are the optimum means of travel. Their versatility and maneuverability have made them popular in areas with difficult flying environments, including Papua New Guinea. In Norway, the Twin Otter paved the way for the network of short-field airports, connecting the rural areas with the larger towns with 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 (takeoff, flight and landing) per year.
Twin Otters are a staple of Antarctic transportation.[11] 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 April 24–25, 2001, two Twin Otters performed the only winter flight to Amundsen-Scott South Pole Station to perform a medical evacuation.[12][13][14][15]
The Argentine Air Force used them on Antarctica [16] since the 1970s with at least one of them deployed the whole year at Marambio Base [17]
As of August 2006, a total of 584 Twin Otter aircraft (all variants) remain in service worldwide. Major operators include: Libyan Arab Airlines (16), Maldivian Air Taxi (17), Trans Maldivian Airways (15), Kenn Borek Air (33) and Scenic Airlines (11). Some 115 airlines operate smaller numbers of the aircraft including Yeti Airlines in Nepal, Malaysia Airlines which uses the Twin Otter exclusively for passenger and freight transportation to the Kelabit Highlands region in Sarawak, and in the United Kingdom the FlyBe francise operator Loganair which uses the aircraft to service the island of Barra in the Hebrides islands. This scheduled service is unique as the aircraft lands on the beach and the schedule is partly influenced by the tide tables. The Twin Otter is also used for landing at the world's shortest commercial runway on the Caribbean island of Saba, Netherlands Antilles.
Ontario's Ministry of Natural Resources is also a long-time operator of the Otter.
Transport Canada still owns three DHC-6 Twin Otters, but they now see very limited flying time, as their role in Coastal Surveillance has been replaced by a fleet of DHC-8 aircraft.
The Twin Otter has been popular with commercial skydiving operations. It is able to carry up to 22 skydivers to over 13,500 ft[18] (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 September 25, 2008, the Series 400 Technology Demonstrator achieved "power on" status in advance of an official rollout.[19][20] First flight of the Series 400 technical demonstrator, C-FDHT, took place October 1, 2008 at Victoria Airport.[21][22] Two days later, the aircraft departed Victoria for a ferry flight to Orlando, Florida, site of the 2008 National Business Aviation Association (NBAA) Conference and exhibition. Viking expects the Series 400 to receive its type certificate from Transport Canada and the European Aviation Safety Agency prior to first delivery of the aircraft in the second quarter of 2010.[4]
The first new build Series 400 Twin Otter (sn 845), made its first flight on February 16, 2010 in Calgary, Alberta.[23]
Variants
- DHC-6 Series 100
- Twin-engined STOL utility transport aircraft, powered by two 550 shp (432 kW) Pratt & Whitney Canada PT6A20 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-engined STOL utility transport aircraft, powered by two 620 shp (462 kW) 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
- 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 300M
- Military version.
- DHC-6 Series 300S
- Six demonstrator aircraft fitted with 11 seats, wing spoilers and an anti-skid braking system.
- DHC-6 Series 400
- Originally scheduled for customer deliveries mid-2009, but now second quarter 2010,[4] powered by two Pratt & Whitney Canada PT6A-34 or optional PT6A-35 Hot & High Performance engines, and available on standard landing gear, straight floats, amphibious floats, skis, wheel skis, or intermediate flotation (Tundra) landing gear.
- CC-138
- Twin-engined STOL utility transport, search and rescue aircraft for the Canadian Forces.
- UV-18A
- Twin-engined STOL utility transport aircraft for the U.S. Army Alaska National Guard. Six built. It has been replaced by the C-23 Sherpa in US Army service.
- UV-18B
- Parachute training aircraft for the United States Air Force Academy. The United States Air Force Academy's 94th Flying Training Squadron maintains three[24] UV-18s in its inventory as freefall parachuting training aircraft,[25] and by the Academy Parachute Team, the Wings of Blue, for year-round parachuting operations.
Operators/Former Operators
Civil operators
- Aeronaves Alimentadoras (defunct)
- Aviastar Mandiri
- Eastern Metro Express/Metro Airlines (USVI)
- Frontier Airlines (1950–1986)
- KAL Aviation (KALAIR)
- Presidencia de la República del Paraguay
- SkyKef
- Skytrail Air Safaris
- Volcanic Air Safaris
- Carib Aviation
- Ansett Australia - Former operator.
- East-West Airlines (Australia) - Former operator.
- MacRobertson Miller Airlines - Former operator.
- Trans Australia Airlines - Former operator.
- Adlair Aviation
- Air Inuit
- Air Labrador
- Air Tindi
- Kenn Borek Air
- Ministry of Natural Resources (Ontario)
- Nakina Air Service
- NorOntair - Former operator.
- North Cariboo Air
- North-Wright Airways
- Provincial Airlines
- Sander Geophysics [26]
- Transwest Air
- Viking Air
- West Coast Air
- Cayman Airways
- Aerovias DAP
- China Flying Dragon Aviation
- Civil Aviation Administration of China - Former operator.
- Aerolinea de Antioquia
- SAM Colombia
- Nature Air
- East African Airways - Former operator.
- Kar-Air
- Malmilento
- Pacific Sun
- AirSea Lines
- Air Antilles Express
- Guyana Airways - Former operator.
- Air Iceland
- Norlandair
- Airfast Indonesia
- Merpati Nusantara Airlines
- Air Jamaica Express - Former operator
- Air Kenya
- MASWings a subsidiary of Malaysia Airlines
- Maldivian Air Taxi
- Trans Maldivian Airways
- Air Mali (1960-1985)
- Harbourair (Malta)
- Air Mauritius
- Nepal Airlines
- Yeti Airlines
- Windward Islands Airways
- Aircalin
- Mount Cook Airline - Former operator.
- Pakistan International Airlines - Former operator, aircraft not in operation.
- Aeroperlas
- Air Panama
- Airlines PNG
- TAP Portugal - Former operator
- Crown Air
- Dorado Wings
- Air Sao Tome and Principe
- Air Seychelles
- Solomon Airlines
- Surinam Airways
- Air Turks and Caicos
- Aurigny Air Services (Guernsey, Channel islands)
- British Antarctic Survey
- Isles of Scilly Skybus
- Loganair operating a franchise from FlyBe.
- Air Illinois
- Air Serv International
- Air Wisconsin
- Allegheny Commuter
- Continental Express
- Crown Airways (Falls Creek, PA)
- Golden West Airlines
- Grand Canyon Airlines
- Ozark Airlines
- Pilgrim Airlines - Former operator.
- Rocky Mountain Airways
- Scenic Airlines
- Seaborne Airlines
- Air Vanuatu
- Yemenia Airlines
Military operators
- Argentine Air Force ( Marambio Base ) / LADE [27]
- Argentine Army
- Australian Army
- Australian Army Aviation
- Military of Benin
- Canadian Forces - CC-138 - Operated by 440 Squadron in Yellowknife, NT
- Chilean Air Force
- Ecuadorian Air Force
- Ethiopian Air Force
- Armed Forces of Haiti
- Jamaica Defence Force
- Royal Norwegian Air Force (Retired from active service)
- Panamanian Air Force (until 1988)
- Philippine Air Force
- Paraguayan Air Force
- Peruvian Air Force
- Sudanese Air Force
- Uganda Police Air Wing
- Ordered by Vietnamese Navy, delivery expected 2012-2014 [28]
Notable accidents and incidents
- On November 18, 1978 a DHC-6 flown to Guyana to rescue Americans from the Jonestown cult was shot up by cultists and abandoned on the Port Kaituma airstrip.
- On July 31, 1981 a Panamanian Air Force (FAP-205) DHC-6 crashed during flight, killing all passengers and crew including General Omar Torrijos Herrera.[29]
- On April 12, 1990 Widerøe Flight 839 crashed in the ocean outside Værøy, Norway due to wind, killing all the five people on board. Værøy Airport was closed following the accident.
- On April 22, 1992 a Perris Valley Skydiving DHC-6 lost power at Perris Valley Airport in California, crashing 200 feet past the runway, killing 14 skydivers and two crew on board; six skydivers survived.[30]
- On March 24, 2001 an Air Caraïbes DHC-6 crashed in the mountains near Gustaf III Airport on Saint Barthélemy in the French West Indies, killing 17 passengers, 2 crew and 1 person on the ground.[31]
- On August 9, 2007 Air Moorea Flight 1121 crashed shortly after taking off from Moorea Temae Airport in French Polynesia; the plane was bound for Tahiti. All 20 occupants, including 19 passengers and one crew member, were killed.[32]
- On May 6, 2007 a French Air Force DHC-6 in support of the Multinational Force and Observers in the Sinai Peninsula crashed, killing one Canadian and eight French peacekeepers.[33]
- On October 8, 2008 a Yeti Airlines DHC-6 was destroyed on landing at Lukla in Nepal; 16 passengers and 2 crew died in the incident, only the pilot survived.[34]
- On August 2, 2009 Merpati Nusantara Airlines Flight 9760 crashed in Indonesia about 37 kilometres (23 mi) south of Oksibil. All 16 people on board were killed.[35]
- On August 11, 2009 Airlines PNG Flight 4684 crashed whilst en route from Port Moresby to Kokoda in Papua New Guinea, killing all 13 on board.[36]
Specifications (300 series)
General characteristics
- Crew: Minimum one, commonly two. (A flight attendant must be on board if there are more than 19 passengers)
- Capacity: 19 or 20 passengers
- Length: 51 ft 9 in (15.77 m)
- Wingspan: 65 ft (19.8 m)
- Height: 19 ft 6 in (5.9 m)
- Wing area: 420 ft² (39 m²)
- Empty weight: between 7,000 lb (3,200 kg) and 8,000 lb (3,628 kg)
- Max takeoff weight: 12,500 lb (5,670 kg)
- Powerplant: 2× Pratt & Whitney PT6A-27 turboprop engines, 620 hp - 680 hp (460 kW - 507 kW) each
Performance
- Maximum speed: 183 knots (210 mph (340 km/h))
- Cruise speed: 143 kt (165 mph (266 km/h))
- Range: 920 nautical miles (1,050 mi (1,690 km))
- Service ceiling: 26,700 ft (8,140 m)
- Rate of climb: 1,600 ft/min (8.1 m/s)
See also
Related development
- de Havilland Canada DHC-3 Otter
- de Havilland Canada Dash 7
Comparable aircraft
- Antonov An-2
- Antonov An-28
- Britten-Norman Islander
- Britten-Norman Trislander
- Fairchild Dornier 228
- GAF Nomad
- Harbin Y-12
- IAI Arava
- LET L-410
- Shorts SC.7 Skyvan
References
- Notes
- ↑ "UV-18". fas.org. Retrieved: May 15, 2010.
- ↑ "Viking Acquires De Havilland Type Certificates." aiabc.com, February 24, 2006. Retrieved: May 15, 2010.
- ↑ "Viking restarts Twin Otter production." flightglobal.com, April 2, 2007. Retrieved: May 15, 2010.
- ↑ 4.0 4.1 4.2 Sarsfield, Kate. "Viking Twin Otter Series 400 certification approaches." Flightglobal', February 3, 2010. Retrieved: May 15, 2010.
- ↑ 5.0 5.1 5.2 5.3 5.4 5.5 "News releases." Viking Air. Retrieved: May 15, 2010.
- ↑ "Twin Otter - Zimex Aviation." zimex.ch. Retrieved: May 15, 2010.
- ↑ Jang, Brent. "The rebirth of a Canadian icon." The Globe and Mail, CTVglobemedia, May 14, 2010. Retrieved: May 15, 2010.
- ↑ Phelps, Mark. "Updated Twin Otter Takes Off." flyingmag.com, October 16, 2008. Retrieved: May 15, 2010.
- ↑ "New Country Opens up for DHC-6 Twin Otter Series 400." afhra.af.mil, July 24, 2008. Retrieved: May 15, 2010.
- ↑ "Viking Lands Three Orders for New Twin Otter Series 400 Aircraft from U.S. Army." vikingair.com, March 18, 2008. Retrieved: May 15, 2010.
- ↑ "NSF PR 01-29 — Civilian Aircraft to Evacuate South Pole Patient." nsf.gov. Retrieved: May 15, 2010.
- ↑ "2001—Doctor Evacuated from the South Pole." www.70south.com. Retrieved: May 15, 2010.
- ↑ Williams, Jeff. "Pilot says pole flight wasn't his most challenging." usatoday.com.
- ↑ "Pilots return after historic South Pole rescue." cbc.ca/news. Retrieved: May 15, 2010.
- ↑ "Aircraft in Antarctica: British Antarctic Survey." antarctica.ac.uk. Retrieved: December 31, 2007.
- ↑ "Official picture." fuerzaaerea.mil. Retrieved: May 15, 2010.
- ↑ Hulcazuk, Sergio. "Twin Otter: El castor patagonico." aeroespacio.com. Retrieved: May 15, 2010.
- ↑ "Skydive Orange Capacity and Altitude." skydiveorange.com. Retrieved: October 19, 2008.
- ↑ "Viking Twin Otter Series 400 Achieves Power On." vikingair.com, September 25, 2008. Retrieved: May 15, 2010.
- ↑ "Twin Otter Shakes Its Wings Over Victoria Skies." canada.com, October 2, 2008. Retrieved: May 15, 2010.
- ↑ "First Flight For New Twin Otter A "Boring" Success." canada.com, October 1, 2008. Retrieved: May 15, 2010.
- ↑ Padfield, R. Randall and Matt Thurber. "Revived Twin Otter Makes First Flight." ainonline.com, October 8, 2008. Retrieved: May 15, 2010.
- ↑ "Twin Otter Series 400 completes maiden sortie." flightglobal.com, February 17, 2010. Retrieved: May 15, 2010.
- ↑ "94 FTS Fact Sheet." afhra.af.mil. Retrieved: August 12, 2009.
- ↑ "UV-18." globalsecurity.org. Retrieved: August 12, 2009.
- ↑ Sander Geophysics (23 June 2010). "Sander Geophysics Acquires Twin Otter Survey Aircraft". http://sgl.com/news/SGL%20Twin%20Otter%20Press%20Release.pdf. Retrieved 13 July 2010.
- ↑ FAA video
- ↑ "Vietnamese Navy Orders DHC-6 Twin-Otter 400s." Defense Industry Daily, 2010. Retrieved: May 15, 2010.
- ↑ "24 years after the accident." Prensa. Retrieved: March 5, 2005.
- ↑ "Perris Valley Aviation Services DHC-6." NTSB, February 17, 1994. Retrieved: May 15, 2010.
- ↑ "Family sues Air Caraibes over crash on St Bathelemy." Bnet, May 9, 2001. Retrieved: May 15, 2010.
- ↑ Clark, Amy S. "20 Thought Dead In Pacific Plane Crash." CBS News, August 9, 2007
- ↑ Aviation Safety: "Accident description: L'Armée de L'Air 742/CB." aviation-safety.net. Retrieved 15 December 2009
- ↑ "Crash." BBC News. Retrieved: October 8. 2008
- ↑ Hradecky, Simon. "Crash: Merpati DHC6 aircraft impacted mountain." Aviation Herald, 16 October 2009. Retrieved: May 15, 2010.
- ↑ "Mixed weather reported before PNG plane crashed." The Australian, August 2, 2009. Retrieved: May 15, 2010.
- Bibliography
- 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.
External links
- Viking Air
- Bush planes
- Ambient cabin audio of a skydiver load in a Twin Otter to 15,000 feet and back again
- Cockpit intercom audio of a skydiver load in a Twin Otter, including demonstration of flight characteristics
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