Runway

Takeoff and landing areas defined on the surface of water for seaplanes are generally referred to as waterways.

[citation needed] In January 1919, aviation pioneer Orville Wright underlined the need for "distinctly marked and carefully prepared landing places, [but] the preparing of the surface of reasonably flat ground [is] an expensive undertaking [and] there would also be a continuous expense for the upkeep.

Originally in the 1920s and 1930s, airports and air bases (particularly in the United Kingdom) were built in a triangle-like pattern of three runways at 60° angles to each other.

[9][10] Runways with non-hard surfaces, such as small turf airfields and waterways for seaplanes, may use the standard numerical scheme or may use traditional compass point naming, examples include Ketchikan Harbor Seaplane Base's Waterway E/W.

In some countries, regulations mandate that where parallel runways are too close to each other, only one may be used at a time under certain conditions (usually adverse weather).

[14] Small airports that host various forms of air traffic may employ additional suffixes to denote special runway types based on the type of aircraft expected to use them, including STOL aircraft (S), gliders (G), rotorcraft (H), and ultralights (U).

This is more common at higher latitudes: for example, Fairbanks International Airport in Alaska renames runways roughly every 24 years, most recently in 2009.

[16] In northern Canada,[17] runways are designated based on true north, which avoids the need to update them.

[citation needed] In 2009 for example, London Stansted Airport in the United Kingdom changed its runway designation from 05/23 to 04/22 during the night.

[34] A line of lights on an airfield or elsewhere to guide aircraft in taking off or coming in to land or an illuminated runway is sometimes also known as a flare path.

A runway may have some or all of the following:[36] According to Transport Canada's regulations,[37] the runway-edge lighting must be visible for at least 2 mi (3 km).

[40] This avoids the need for automatic systems or staff to turn the lights on at night or in other low visibility situations.

For a major airport, where the ground conditions permit, the most satisfactory type of pavement for long-term minimum maintenance is concrete.

Where it can be anticipated that major settlements of the runway will occur over the years because of unstable ground conditions, it is preferable to install asphalt concrete surface, as it is easier to patch on a periodic basis.

For heavy-duty commercial aircraft, the pavement thickness, no matter what the top surface, varies from 10 to 48 in (25 to 122 cm), including subgrade.

Experience has shown that the K values on which the formula was developed are not applicable for newer aircraft with very large footprint pressures.

A more recent method is an analytical system based on the introduction of vehicle response as an important design parameter.

Essentially it takes into account all factors, including the traffic conditions, service life, materials used in the construction, and, especially important, the dynamic response of the vehicles using the landing area.

Runway pavement surface is prepared and maintained to maximize friction for wheel braking.

To maintain the macrotexturing built into the runway by the grooves, maintenance crews engage in airfield rubber removal or hydrocleaning in order to meet required FAA, or other aviation authority friction levels.

A runway of at least 1,800 m (5,900 ft) in length is usually adequate for aircraft weights below approximately 100,000 kg (220,000 lb).

The Boeing 747 is considered to have the longest takeoff distance of the more common aircraft types and has set the standard for runway lengths of larger international airports.

[43] At sea level, 3,200 m (10,500 ft) can be considered an adequate length to land virtually any aircraft.

Another example is that the Luleå Airport in Sweden was extended to 3,500 m (11,483 ft) to allow any fully loaded freight aircraft to take off.