De Havilland Canada DHC-6 Twin Otter - Operational History

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.

A number of commuter airlines in the United States got their start by operating Twin Otters in scheduled passenger operations. One commuter air carrier, Houston Metro Airlines (which later changed its name to Metro Airlines), even constructed their own STOLport airstrip with passenger terminal and maintenance hangar in Clear Lake City, Texas near the NASA Johnson Space Center. The Clear Lake City STOLport was specifically designed for Twin Otter operations. At one point, Houston Metro operated twenty-two (22) round trip flights every weekday between Clear Lake City (CLC) and Houston Intercontinental Airport (IAH, now Houston 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 Airlines at Houston Intercontinental, with this major airport even having a dedicated STOL landing area at the time specifically for Twin Otter flight operations.

Another commuter airline in the U.S., Rocky Mountain Airways, operated Twin Otters from the Lake County Airport in Leadville, CO. At an elevation of 9,927 feet above mean sea level, this airport is the highest airfield in the U.S. ever to have received scheduled passenger airline service, thus demonstrating the wide ranging flight capabilities exhibited by the Twin Otter.

Larger airlines in the U.S. and Canada also flew Twin Otter aircraft. For example, Alaska Airlines, the original Frontier Airlines and Wien Air Alaska were all jet operators that flew Boeing 727 aircraft as well as earlier versions of the Boeing 737 at the time. All three airlines operated Twin Otter aircraft as well. Ozark Airlines was primarily a Douglas DC-9 jetliner operator that also flew Twin Otters. In addition, Pacific Western Airlines (PWA) and Transair, which were Canadian air carriers that flew Boeing 737 jets, both operated Twin Otter aircraft as well. Two other Canadian airline that flew Twin Otters, Time Air and NorcanAir, also operated Fokker F28 Fellowship passenger jets. 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 have never received air service.

Twin Otters are also a staple of 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 April 24–25, 2001, two Twin Otters performed the only winter flight to Amundsen-Scott South Pole Station to perform a medical evacuation.

The Argentine Air Force used them on Antarctica since the 1970s with at least one of them deployed the whole year at Marambio Base The Chilean Air Force also operates the type from 1980, usually having an example based at Presidente Frei Antarctic base of South Shetland islands.

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 (22), Trans Maldivian Airways (23), Kenn Borek Air (42) 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 franchise 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 Twin Otter.

Transport Canada still owns three DHC-6 Twin Otter aircraft, 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 (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. First flight of the Series 400 technical demonstrator, C-FDHT, took place October 1, 2008 at Victoria Airport. 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. The first new build Series 400 Twin Otter (SN 845) made its first flight on February 16, 2010 in Calgary, Alberta. Transport Canada presented Viking Air Limited with an amended DHC-6 Type Certificate including the Series 400 on July 21, 2010.