Runway

The start and runway (SLB ) is the (usually fixed ) area of ​​an aerodrome or aircraft carrier, on the one hand off aircraft accelerate to lift-off speed and then lift the other hand and put brake or roll out landing aircraft. For the acceleration a longer runway length is required as for the braking distance on landing. Most slopes are used for both takeoffs and landings; in rare cases, factors such as an obstacle situation or a special rolling logistics require exclusive use for takeoffs or landings. This is, for example, at Frankfurt am Main Airport is the case.

In English usage, so also there is only the expression of runway (abbreviated as RWY ). In the German technical language slopes or short web is synonymous with start and runway used. In Switzerland and in the German- air radio is used solely by the name slopes.

A web is used for safety at all times by only one plane, in particular if it is used as a starting and landing runway. This is, however, partly in very quick succession, especially at airports with high utilization is often observed that at the end of the runway versus a plane, while another aircraft is on the other side just before landing. Because each aircraft caused a wake behind him, a certain distance between departing and landing aircraft is maintained.

These tracks belong to the airport infrastructure.

Structural design

Surface / sub

As a start- off and landing runway one defines a (often fortified ) surface which is suitable for launching and landing of airplanes. It must be applied in its design so that it can withstand the associated charges.

Depending on the requirements can be constructed very different start and runways. While light aircraft can start from simple short mown grass paths from, this is heavy commercial aircraft is not possible because its landing gear would sink into the ground. Each commercial airport has now therefore at least a fortified airstrip. The thickness of the linings of the tracks is between 25 cm to 130 cm for heavily loaded paths as in the new southern runway of the Berlin Brandenburg Airport. They are made of either asphalt or concrete. Concrete is used due to its longer life of up to 40 years esp. on large airfields. The lower asphalt with a lifetime of 15 to 20 years often comes at smaller airports for use. The surfaces must be in the most diverse weather conditions have a good friction behavior and be free of irregularities to ensure the best possible sequence of movements.

The slopes consist addition to the aforementioned substrates but also from gravel or sand. They are as smooth as possible built to ensure smooth startup of the aircraft. For concrete slopes the soil is often in length grooved ( " Grooving ") so that the water can drain away and no hydroplaning occurs.

The biggest problem of the grass slopes is that they can become unusable after heavy rains for a long time. To prevent this, the soil is drained either before the construction of the airport or the floor with reinforced grids (eg airfield Bacon Fehraltorf LSZK in Switzerland). The carrying capacity of the railways can be classified with the Pavement Classification Number.

Even with landing sites for seaplanes one speaks in part from the start and runways.

Length and width

The length and width of the start and runway depends on the rated aircraft. Is the aircraft, which is operated on the corresponding runway most common. A possible exception permit will be issued for larger aircraft in need. Thus, the use of large aircraft on intercontinental routes can lead to a very high maximum takeoff weight, which in turn may require a runway length of 3,000 to 4,000 m. Is the required length is not given, this results in restrictions on the aircraft in terms of their weight and therefore their scope. Site-specific factors also have an impact on the minimum length of the slopes. Reduced engine power and a deteriorated buoyancy caused by ...

• High temperatures at the location ( warm air expands and is therefore thinner than cold ). Therefore, the paths must be extended depending on the percentage aerodrome reference temperature. This corresponds to the average daily maximum temperature of the hottest month of the year.
• The high location of an aerodrome above the sea resulting lower air pressure.

The width of the start and runways is also affected by the specifications of the aircraft. For the most common, major aircraft types, the standard width of many rail of 45 meters is sufficient. A wide-body aircraft such as the A380 requires a web width of 60 meters. However, the A380 Airport Compatibility Group ( AACG ) granted an exemption for 45 m wide runways for certain airfields.

In the military airfields, the start and runways are also built according to the types of aircraft which they are to use. The railway has at the big transport planes to be 2.5 km long, while hunting aircraft require shorter distances and get on smaller propeller aircraft with very short distances.

Some ultralights satisfies a takeoff or landing distance of well below 100 m. Ultralight flying site typically have grass paths around 250 m in length.

Be divided the paths which are expressed by a two-digit code according to ICAO Annex 14 in four lengths and six width categories. This code is always as follows consists of:

• Code number 1: less than 800 meters reference runway length
• Code number 2: 800 meters to less than 1200 meters reference runway length
• Code number 3: 1200 meters to 1800 meters less respect runway length
• Code number 4: 1800 meters and more respect runway length

For the classification, a minimum width is necessary for new plants this pathway is not otherwise authorized

• Code letter A: wingspan up to less than 15 meters and main landing gear width to less than 4.5 meters
• Code letter B: wingspan of 15 to less than 24 meters and main landing gear width of 4.5 to less than 6 meters
• Code letter C: wingspan of 24 to less than 36 meters and main landing gear width from 6 to less than 9 meters
• Code letter D: wingspan of 36 to less than 52 meters and main landing gear width of 9 to less than 14 meters
• Code letter E: wingspan of 52 to less than 65 meters and main landing gear width of 9 to less than 14 meters
• Code letter F: wingspan of 65 to less than 80 meters and main landing gear width of 14 to less than 16 meters

The longest railway in the world in civil aviation has a length of 5,500 meters (14/ 32) at the Qamdo Bamda Airport ( ICAO code: ZUBD ) in the Tibet Autonomous Region ( China ). The shortest path of an international commercial airport for airplanes with jet engines has the airport Yap (Micronesia) with 1,469 meters.

Immediately at the start and runway around the security strip is set to authorization by law. This has, depending on the size of the airstrip and use ( instrument flight rules (IFR ) / visual flight ( VFR) ) has a width of 30 m (VFR ) on the right and left of the railway up to 150 m (IFR, code number 3 and 4), depending page and must be leveled and free of obstacles. Within the strip itself may be an obstacle from air traffic control reasons, only the Gleitwegsendemast and the monitor are fattening. The strip starts at 30 m ( VFR) to 60 m ( IFR) in front of the train and ends at 30 m or 60 m after the end of the track. Before and behind the strip is in each case the RESA ( runway end safety area - Start-/Landebahnendsicherheitsfläche ). The RESA has a length of min. 30 m ( VFR) up to 90 m (IFR, ICAO recommended 240 m at IFR). The width is that of the strip, but at least twice the width of the web.

The point on the path on which a landing aircraft must touch down earlier than is called a landing threshold (english Threshold). The mark that threshold looks like a zebra crossing. Must be distinguished from the real touchdown, depending on the track length, aircraft and wind conditions, more or less far behind the threshold.

At the end of the path can be established under certain circumstances, depending on the obstacle situation an open space ( Clearway ). Their length is determined with the existing boot drive route TORA ( take-off run available) the TODA ( take-off distance available ). Similarly, a stopway could be set up under certain circumstances. This stopway is added to the existing TORA and gives the maximum ASDA ( accelerate stop distance available ).

Orientation

While previously the airfields in Germany usually around [ source? ], And so in each direction could be used, today the start and runways are built so that they are adapted in their direction the local wind conditions. Planes take off and land in principle against the wind to generate maximum lift and shorten the start and landing distance. For this reason, the main line is ideally built to the prevailing wind direction. Slight deviations may be necessary due to geographical conditions and approach procedures. The location of other paths should be chosen so that the usability factor of the airport is at least 95 %. This means that if often prevail in one location so strong cross winds that the main path can not be operated continuously, should a cross- wind track be present. The smaller the aircraft that is to use the web, the lower the allowable crosswind component. To plan the start and runway orientations should several times daily observations of wind distribution be made at least five years to ensure maximum usability of the tracks.

A particularly difficult situation arises when wind shear situations ( engl. wind hear ) prevail on the start and runway. Wind shear are redirected through the floor updrafts and downdrafts that occur as strong gusts in appearance. In weather radar you can indeed detect bad weather areas well in advance and fly around, wind shear, are not displayed.

However, there is now a so-called wind hear warning system, which not only detects wind shear, if it occurs current (caused by more than 15 kts vertical or 500 fpm horizontal deviation ( Def ) ), but also a so-called " Predictive Windshear System", which lies well ahead of the aircraft detects large up and down washes. If the risk is too great to be landed at any other airport.

Configurations

Meteorological and geographical factors on airfields require different configurations of the start and runways. Possible configurations are one-way, the parallel runway, the cross rail and the V- rail system, and combinations thereof. The capacity than maximum number of flight movements is largely, but not exclusively determined by the rail system. More kapazitätslimitierende factors are wind and visibility conditions, delays in heavy traffic, graduations, existing navigation aids, aircraft mix, arrival and departure procedures as well as the capacity of the aprons and taxiways. The calculated in this capacity does not constitute an absolute value, but a simulated approximation.

The simplest variant is the one-way system in which only a start and runway is present in the main wind direction. It is esp. from small airports used which lay claim to no adverse cross winds. This system can be implemented depending on the ground technical equipment annually 180,000 to 230,000 aircraft movements.

In a parallel runway system two or more paths exist in a parallel arrangement. This implies as in the one-way system that at the site, are hardly strong headwinds that would limit the operation available. The distance and the offset of the tracks are spaced crucial to how many movements and capacity are increased. This distance, which determines which mode is measured from each other based on the distance of the track center lines. Here there is a distinction between near-, far -and middle- path distance ( "close", "far", "intermediate "). A distance of about 1,035 m means that the tracks can be operated independently of each other under any conditions (except for threshold offset of the two tracks ). This leads to a doubled capacity of up to 120 movements per hour or 310000-380000 flight movements per year. At a distance of 1,035 m under no independent operation of both pathways is possible. Depending on the distance produces differently strong dependencies, which can reduce the capacity of the rail system to the maximum capacity of a one-way operation.

When cross rail system is two tracks of different orientation that intersect at one point. The different orientation of the paths is due to winds from different directions. Were in such locations only tracks an alignment exists, this would lead to a capacity limitation in strong crosswind conditions. By the tracks of different orientation ensures that a path is always equal to the wind conditions. At low wind speeds, both tracks can even be operated. The capacity is in addition to the operating direction strongly depends on the position of the intersection point of the two lanes at the cross rail system. The smaller the distance of the intersection of the ends of the traces, the greater the capacity of the system.

The V -Bahn system is similar in configuration to the cross rail system, but the two tracks of different geographic direction does not cut it. The web with the prevailing direction of operation is also referred to as a main path, and the other as a cross wind web accordingly. With strong wind, the capacity is limited because in this case, only one web can be operated. In contrast, both paths can be used simultaneously in light winds. A higher capacity is achieved when the movements take place from V leading away. In this case, can take place up to 100 aircraft movements per hour.

Exemplary arrangements ( pictorially )

Four times crossing the tracks ( San Francisco USA airport)

Six-fold intersection of the paths (Boston, USA )

Inclination

The start and runway may only have a small inclination angle of a few degrees in Europe, as the start was uphill more difficult, and a landing on an inclined track is much more difficult. A renewal of the 10 % of the reference runway length must be 1% per longitudinal inclination of the orbit, since a difference in altitude within the runway has a lower acceleration capability of the aircraft resulted.

Maximum longitudinal slope:

But even then there are exceptions: the Alps Courchevel airport has a orbital inclination of 18.5 % or about 11 °. In such Altiports can be landed only in one direction and started in the opposite direction due to strong orbital inclination or other geographical features often.

Special case of aircraft carrier

On large aircraft carriers with an angle flight deck there are two separate paths. As can be only started by the bow addition, the extended runway which is angled a few degrees from the longitudinal axis, are used for takeoffs and landings. Smaller support with straight flight deck, which have a combined start and runway, set at the end of a runway a "Ski - Jump", which propels the aircraft into the air.

Runway identifier

The webs are with their runway identifier ( engl. runway designator ) indicates that based on the degrees of the compass rose. The level number is divided by ten and rounded. Runs as a web in east-west direction ( 90 or 270 degrees ) it will have the label 09/27. The smaller number is always first, regardless of the currently used operating direction of the web. A path which is referred to in one direction at 04, is the identification result in the opposite direction 22. The direction of the tracks differs by 180 degrees, marking ie by 18 Each of these two numbers is as large white number at the respective threshold ( the beginning of the landing distance LDA) painted on the track, so that they by the pilot from the air, from some distance can be detected.

Since the pilot is oriented at landing on his magnetic compass, the markings depend on the earth's magnetic field. A runway with the marking 36 thus has, in the direction of the field lines of the local earth's magnetic field, and thus not necessarily the geographical North Pole. The deviation is in Germany only a few degrees, in other countries it can be significantly higher. In addition, since a permanently changing the Earth's magnetic field, also the identifiers of existing paths can change. For example, the web 15 /33 Sylt airport was renamed in June 2006 on 14/32, because the allowance for variation resulted in a miss -setting value which is closer to the 14/32.

If an airfield has two start and runways which are parallel and thus have the same numbers as marking, the right-most path of the letter R is added ( from the English right) and the left track an L ( from the English left ). The full marking would in such a case, for example, runway 07R and runway 07L. If there is even a third parallel track, the letter C is used ( from the English center) for the mean slope. If more than three parallel paths ( for example, at the Los Angeles airport) the names of two webs are often rounded, while the name for the other two lanes will be rounded up. The four tracks in compass direction 249 are then referred to as an example 25R, 25L, 24R and 24L.

In flight mode, only one direction is always used. This sets the Tower and is based as a rule on the current wind direction to allow aircraft take-offs and landings into the wind in order to achieve short takeoff and landing runs routes. It may happen that the operating direction is changed during flight operations. Is then 36 from operating direction 18, ie, takeoffs and landings can no longer find in the south but to the north instead.

Markers

The starting and landing strips continue to have white markings which help the pilot during the start-up, and particularly during landing, to identify the various portions of the web and its central axis in order to safely maneuver in this way. In the right picture the mark is valid for a code number -4- (train length greater than 1800 meters ).

Firing

For take-offs and landings at night and in fog have some takeoff and landing paths over a firing, which marks the lateral boundary, the center, the beginning and the end of the track and some of the sections.

• All taxiways ( runways ) are fired with green lights ( blue edges ), the holding point for runway center line green (green - yellow if CAT-II/III-Schutzzonen are affected by the ILS).
• Start and runways are fired at the edges with white lights. The center line marking is also fired white; at CAT II / III of the final 900 meters, 600 meters red and white and the last 300 meters coded red only. The end is fired red, the green landing threshold, the Landebahnaufsetzzone white (only for CAT II / III).
• The roll stop is fired red, and it may be illuminated signs (yellow) available. CAT-II/III-Halteorte are also fired red and with red signs.
• Intermediate holding positions are fired orange.
• The apron has blue edge lights and headlights.

Approach lights are distinguished for precision approaches and non - precision approaches. Precision approaches require a minimum length of 720 meters approach lights (with ILS CAT I) in CAT II and CAT III 900 meters.

Paths for non- precision approaches should be equipped with at least 720 meters long approach lighting. Exceptions up to 420 meters are possible. Under certain physical conditions ( slope or similar) is also a shorter length of the approach lights, but under other conditions is possible, for example, in Allendorf / Eder: GPS approach procedure, but only 150 meters approach lighting (although raising the MDH).

Some lights in landing approach, called VASI, allow for a review of the three -degree descent to the path through two or four consecutively arranged headlamps ( "White white: your height, red white: you're right, red red: you're dead. "). A more precise landing aid offers the Precision Approach Path Indicator System ( PAPI ), which uses four next to each other lamps. Again, there is a color code of red ( too low ) and white ( too high); the correct glide path is reached when the pilot sees two red and two white lights.

Operation

Aircraft are often associated with larger airfields by a follow -me car from the runway to the parking position. In particular, it is common for aircraft that are not handled at a gate or self- GAT roll, be accompanied by a follow-me car to its parking position. At the gates of large airports will provide instructions by ground staff, so-called marshaler.

In certain weather conditions, the web can be used only when it has been cleared of snow and treated for defrosting or to prevent ice formation with movement area.

Airports with many runways

The airports of Dallas / Fort Worth and Chicago ( the second largest passenger traffic worldwide) have seven start and runways. About six lanes has the U.S. geographically largest airport, Denver International Airport, while the airport with the world's highest number of passengers, the Atlanta airport, has "only" about five lanes. The largest Dutch Amsterdam Airport also has six lanes. The Paris-Charles de Gaulle, Frankfurt airport and the largest airport in Japan, the Tokyo International Airport, have four lanes, while the largest airport of Belgium, the Brussels Airport, has three tracks. The airport London Heathrow ( 's largest international passenger traffic in Europe, the third largest total passenger traffic worldwide) has three tracks, of which only two are in operation.

Dubai is currently building ( 20xx ) on the "greatest airport in the world ", the Al Maktoum International Airport. He is said to have as a supplement to the existing Dubai International Airport for five parallel-arranged start and runways and a capacity of 160 million passengers. This is to be surpassed with 8 planned start and runways from Beijing Daxing Airport, whose construction is planned for early 2014.

Start and runways of the German airfields

In international comparison, Germany's airports have a relatively small number of start and runways. The list of international airports in accordance with the directive of the BMVBS includes 16 airfields. Among them, only the Frankfurt airport has four lanes. With a current maximum of three railways, airports Hanover and Cologne / Bonn feature. Six of them have two slopes: Berlin Tegel, Bremen, Dusseldorf, Hamburg, Leipzig / Halle and Munich. The remaining seven airports have only one start and runway.

• The new Berlin Brandenburg Airport (BER ) will have two parallel takeoff and landing paths: the former Southern Railway of Berlin- Schönefeld, which will be extended as part of the new building at 3600 meters, and a new runway 4000 meters long and 60 meters wide.
• Nuremberg Airport: The majority of the restoration work on the 2700 -meter-long airstrip was completed in summer 2010. In several sections in the core over 50 years old runway is to be renewed gradually up to 2015 and equipped with modern technology.