A polar route refers to an aircraft route across the uninhabited polar ice cap region. The American Federal Aviation Administration defines the North Polar area of operations as the area lying north of 78 deg north latitude [1], which is entirely north of Alaska and most of Siberia. The term "polar route" was originally more general, being applied to great circle routes between Europe and the west coast of North America in the 1950s.[2] During much of the Cold War the Arctic region was a buffer zone between the Soviet Union and North America; civilian flights from Europe to the Asian Far East were unable to cross the Soviet Union or China and had to use a Middle East route or connect through Alaska across the Arctic region. These Cold War tracks extended from the northern Alaskan coast across Greenland to Europe. Korean Air Lines Flight 902 was shot down in the USSR in 1978 after the crew made gross navigational errors attempting to fly the assigned polar route.
Routine transpolar flight deep into the Arctic became possible only after the end of the Cold War, when the United States and Russia became less concerned about the possibility of a trans-polar attack. Aircraft such as the Boeing 747-400 and the Airbus A340, with ranges of around 7,000 nautical miles (13,000 km), were also required to handle the distances between suitable airports.[3] Before this era, all flights from North America to Asia were routed around the Communist bloc using a series of tracks between Alaska and Japan.
The main obstacle to flights across Russia was the inadequate Russian air traffic control system and a lack of English communication. To solve these issues RACGAT (Russian-American Coordinating Group for Air Traffic) was formed in 1993. By summer 1998 the Russian government gave permission to open four cross-polar routes, named Polar 1, 2, 3 and 4 [4]. Cathay Pacific flew the first polar flight into Siberia in July 1998.
Polar routes are now in common use by airlines connecting Asian cities such as Singapore, Hong Kong, Beijing, Tokyo, and Seoul to North American destinations such as New York, Chicago, Washington, Detroit, and Toronto.
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In the southern hemisphere, most intercity pairs do not result in a great circle route over Antarctica. Although direct flights between South Africa and New Zealand would overfly Antarctica, there never have been direct flights between those countries.
Aerolíneas Argentinas and LAN Chile operate nonstop services from New Zealand to Buenos Aires and Santiago, respectively, and Qantas flies nonstop from Sydney to Buenos Aires, forming the most southerly polar route. Depending on flight-level winds, these can approach 55 degrees southerly latitude, though not enough to cross the polar ice cap.
The FAA's policy letter Guidance for Polar Operations (March 5, 2001) outlines a number of special requirements for polar flight, which includes two cold-weather suits, special communication capability, designation of arctic diversion airports and firm recovery plans for stranded passengers, and fuel freeze strategy and monitoring requirements [5]
Jet fuel freeze temperatures range between -40 and -50 °C. These temperatures are frequently encountered at cruise altitude throughout the world with no effect since the fuel retains heat from lower elevations, but the intense cold and extended duration of polar flights may cause fuel temperature to approach its freezing point. Modern long-distance airliners are equipped to alert flight crew when fuel temperatures reach these levels. The crew must then change altitude, though in some cases due to the low stratosphere over polar regions and its inversion properties the air may actually be somewhat warmer at higher altitudes.