Zurich Airport known as Kloten Airport, is the largest international airport of Switzerland and the principal hub of Swiss International Air Lines. It serves Zürich, Switzerland's largest city, with its surface transport links, much of the rest of the country; the airport is located 13 kilometres north of central Zürich, in the municipalities of Kloten, Rümlang, Oberglatt and Opfikon, all of which are within the canton of Zürich. The first flight abroad from Switzerland landed on July 21, 1921. In the early years of aviation, the Dübendorf Air Base, located some 8 km to the south-east of Zurich Airport served as the city's commercial airfield; the need for a dedicated commercial facility led to the search for a location at which to build a replacement airport. Switzerland's federal parliament decided in 1945 that Zürich was to be the site of a major airport, sold 655 hectares of the Kloten-Bülach Artillery Garrison to the Canton of Zürich, giving the canton control of the new airfield. Construction of the airport began the following year.
Initial plans for the airport, as laid out in the Federal government's scheme of 1945, were centered on facilities capable of handling international airline traffic. Aircraft of up to 80 tons were envisaged; the primary runway was to be designed for use in all weathers and at night, with a 400-metre -wide hard surface running to 3,000 metres in length. Additional 100-metre areas were to be provided on the shoulders for lateral protection in case of runway excursions. Additional domestic runways, between 1,000 and 1,400 metres in length, were to be built; the first flights from the west runway were not until 1948. The new terminal opened in 1953 with a large air show. In 1947, the airport handled 133,638 passengers on 12,766 airline flights; the first expansion of the airport was submitted in 1956. The airport was again submitted and approved for renovation in 1970, Terminal B was completed in 1971; the first signs of noise mitigation for the airport were in 1972, when a night-time curfew was enacted, as well as in 1974 when new approach routes were introduced.
Runway 14/32 was opened in 1976, 16/34 began renovation. The noise of aircraft became an issue at Zurich Airport; the next major event for the airport was in 1999, when the Parliament of the Canton of Zürich approved privatization of Zurich Airport. The following year, Flughafen Zürich AG, trading under the brand Unique, became the new airport operator; the company dropped the brand Unique in favour of Zurich Airport and Flughafen Zürich in 2010. On 2 October 2001 a major cash-flow crisis at Swissair, exacerbated by the global downturn in air travel caused by the September 11 attacks, caused the airline to ground all its flights. Although a government rescue plan permitted some flights to restart a few days and the airline's assets were subsequently sold to become Swiss International Air Lines, the airport lost a large volume of traffic. After Lufthansa took control of Swiss International Air Lines in 2005, traffic began to grow again. On 18 October 2001, Germany and Switzerland signed a treaty regarding the limitation of flights over Germany.
Under the terms of this treaty, any incoming aircraft after 22:00 had to approach Zürich from the east to land on runway 28, unlike the airport's other runways, was not equipped with an instrument landing system. A month at 22:06 on 24 November, an inbound Crossair Avro RJ100 using this approach in conditions of poor visibility crashed into a range of hills near Bassersdorf and exploded, killing 24 of the 33 people on board; the flight had been scheduled to land on runway 14 before 22:00, but it was subject to delay and was therefore diverted to runway 28. Zurich Airport completed a major expansion project in 2003, in which it built a new parking garage, a new midfield terminal, an automated underground people mover to link the midfield terminal to the main terminal. In November 2008 a complete renovation and rebuild of the old terminal B structure was announced; the new terminal B opened in November 2011, provides segregated access to and from aircraft for Schengen and non-Schengen passengers.
Zurich Airport handled 25.5 million passengers in 2014, up 2.5 percent from 2013. Etihad Regional ceased on 18 February 2015 to fly two-thirds of its scheduled routes without further notice, amongst them all its services from Zürich except the domestic service to Geneva. Etihad Regional blamed the failure of its expansion on the behavior of competitors Swiss International Air Lines, as well as the Swiss aviation authorities; as a consequence of the bombings in Brussels on 22 March 2016, which caused the temporary closure of Brussels Airport, Brussels Airlines stationed three Airbus A330s at Zurich Airport to offer flights to several African countries for the duration of the closure. The airport is owned by a company quoted on the SIX Swiss Exchange. Major shareholders include the canton of Zürich, with 33.33% plus one of the shares, the city of Zürich, with 5% of the shares. No other shareholder has a holding exceeding 3%. Flughafen Zürich AG used the brand name Unique from 2000 until 2010. In March 2017, Flughafen Zürich AG announced it had acquired 100% of Brazil's Hercílio Luz International Airport, will operate it under a concession until 20
Visual approach slope indicator
The visual approach slope indicator is a system of lights on the side of an airport runway threshold that provides visual descent guidance information during approach. These lights may be visible from up to 8 kilometres during the day and up to 32 kilometres or more at night. Basic visual approach slope indicators consist of one set of lights set up some 7 metres from the start of the runway; each light is designed so that it appears as either white or red, depending on the angle at which it is viewed. When the pilot is approaching the lights at the proper angle, meaning the pilot is on the glide slope, the first set of lights appears white and the second set appears red; when both sets appear white, the aircraft is too high, when both appear red it is too low. This used to be the most common type of visual approach slope indicator system. A mnemonic to remember the colors and their meaning is: White over White, you're high as a kite / you'll fly all night / check your height Red over White, you're alright.
Red over Red, you're dead. White over Red, unsaid / you're under head. Leading lights, similar aid to navigation Pilot controlled lighting Precision approach path indicator Runway end identifier lights Runway edge lights Approach lighting system FAA Aeronautical Information Manual, Chapter 2, Section 1 FAA Aeronautical Information Manual
In photometry, luminous intensity is a measure of the wavelength-weighted power emitted by a light source in a particular direction per unit solid angle, based on the luminosity function, a standardized model of the sensitivity of the human eye. The SI unit of luminous intensity is an SI base unit. Photometry deals with the measurement of visible light; the human eye can only see light in the visible spectrum and has different sensitivities to light of different wavelengths within the spectrum. When adapted for bright conditions, the eye is most sensitive to greenish-yellow light at 555 nm. Light with the same radiant intensity at other wavelengths has a lower luminous intensity; the curve which measures the response of the human eye to light is a defined standard, known as the luminosity function. This curve, denoted V or y ¯, is based on an average of differing experimental data from scientists using different measurement techniques. For instance, the measured responses of the eye to violet light varied by a factor of ten.
Luminous intensity should not be confused with another photometric unit, luminous flux, the total perceived power emitted in all directions. Luminous intensity is the perceived power per unit solid angle. If a lamp has a 1 lumen bulb and the optics of the lamp are set up to focus the light evenly into a 1 steradian beam the beam would have a luminous intensity of 1 candela. If the optics were changed to concentrate the beam into 1/2 steradian the source would have a luminous intensity of 2 candela; the resulting beam is brighter, though its luminous flux remains unchanged. Luminous intensity is not the same as the radiant intensity, the corresponding objective physical quantity used in the measurement science of radiometry. Like other SI base units, the candela has an operational definition—it is defined by the description of a physical process that will produce one candela of luminous intensity. By definition, if one constructs a light source that emits monochromatic green light with a frequency of 540 THz, that has a radiant intensity of 1/683 watts per steradian in a given direction, that light source will emit one candela in the specified direction.
The frequency of light used in the definition corresponds to a wavelength in a vacuum of 555 nm, near the peak of the eye's response to light. If the source emitted uniformly in all directions, the total radiant flux would be about 18.40 mW, since there are 4π steradians in a sphere. A typical candle produces roughly one candela of luminous intensity. Prior to the definition of the candela, a variety of units for luminous intensity were used in various countries; these were based on the brightness of the flame from a "standard candle" of defined composition, or the brightness of an incandescent filament of specific design. One of the best-known of these standards was the English standard: candlepower. One candlepower was the light produced by a pure spermaceti candle weighing one sixth of a pound and burning at a rate of 120 grains per hour. Germany and Scandinavia used the Hefnerkerze, a unit based on the output of a Hefner lamp. In 1881, Jules Violle proposed the Violle as a unit of luminous intensity, it was notable as the first unit of light intensity that did not depend on the properties of a particular lamp.
All of these units were superseded by the definition of the candela. The luminous intensity for monochromatic light of a particular wavelength λ is given by I v = 683 ⋅ y ¯ ⋅ I e, where Iv is the luminous intensity in candelas, Ie is the radiant intensity in watts per steradian, y ¯ is the standard luminosity function. If more than one wavelength is present, one must sum or integrate over the spectrum of wavelengths present to get the luminous intensity: I v = 683 ∫ 0 ∞ y ¯ ⋅ d I e d λ d λ. Brightness International System of Quantities Radiance
Runway end identifier lights
Runway end identifier lights are installed at many airports to provide rapid and positive identification of the approach end of a particular runway. The system consists of a pair of synchronized flashing lights located laterally on each side of the runway threshold. REILs may be either unidirectional facing the approach area, they are effective for: Identification of a runway surrounded by a preponderance of other lighting Identification of a runway which lacks contrast with surrounding terrain Identification of a runway during reduced visibilityThe International Civil Aviation Organization recommends that: Runway threshold identification lights should be installed: at the threshold of a non-precision approach runway when additional threshold conspicuity is necessary or where it is not practicable to provide other approach lighting aids. Runway threshold identification lights shall be located symmetrically about the runway centre line, in line with the threshold and 10 meters outside each line of runway edge lights.
Runway threshold identification lights should be flashing white lights with a flash frequency between 60 and 120 per minute. The lights shall be visible only in the direction of approach to the runway. FAA Aeronautical Information Manual
Approach lighting system
An approach lighting system, or ALS, is a lighting system installed on the approach end of an airport runway and consisting of a series of lightbars, strobe lights, or a combination of the two that extends outward from the runway end. ALS serves a runway that has an instrument approach procedure associated with it and allows the pilot to visually identify the runway environment and align the aircraft with the runway upon arriving at a prescribed point on an approach. Modern approach lighting systems are complex in their design and enhance the safety of aircraft operations in conditions of reduced visibility; the required minimum visibilites for instrument approaches is influenced by the presence and type of approach lighting system. In the U. S. a CAT I ILS approach without approach lights will have a minimum required visibility of 3/4 mile, or 4000 foot runway visual range. With a 1400-foot or longer approach light system, the minimum potential visibility might be reduced to 1/2 mile, the presence of touchdown zone and centerline lights with a suitable approach light system might further reduce the visibility to 3/8 mile.
The runway lighting is controlled by the air traffic control tower. At non-towered airports, pilot-controlled lighting may be installed that can be switched on by the pilot via radio. In both cases, the brightness of the lights can be adjusted for night operations. Depth perception is inoperative at the distances involved in flying aircraft, so the position and distance of a runway with respect to an aircraft must be judged by a pilot using only two-dimensional cues such as perspective, as well as angular size and movement within the visual field. Approach lighting systems provide additional cues that bear a known relationship to the runway itself and help pilots to judge distance and alignment for landing. After World War II, the U. S. Navy and United Airlines worked together on various methods at the U. S. Navy's Landing Aids Experimental Station located at the Arcata–Eureka Airport, California air base, to allow aircraft to land safely at night and under zero visibility weather, whether it was rain or heavy fog.
The predecessor of today's modern ALS while crude had the basics — a 3,500 foot visual approach of 38 towers, with 17 on each side, atop each 75 foot high tower a 5000 watt natural gas light. After the U. S. Navy's development of the lighted towers it was not long before the natural gas lights were soon replaced by more efficient and brighter strobe lights called Strobeacon lights; the first large commercial airport to have installed a strobe light ALS visual approach path was New York City's John F. Kennedy International Airport. Soon other large airports had strobe light ALS systems installed. All approach lighting systems in the United States utilize a feature called a decision bar. Decision bars are always located 1000′ farther away from the threshold in the direction of the arriving aircraft, serve as a visible horizon to ease the transition from instrument flight to visual flight. Approach lighting systems are designed to allow the pilot to and positively identify visibility distances in Instrument meteorological conditions.
For example, if the aircraft is at the middle marker, the middle marker is located 3600 feet from the threshold, the Decision Bar is 2600 feet ahead. If the procedure calls for at least half a statute mile flight visibility, spotting the Decision Bar at the marker would indicate enough flight visibility to continue the procedure. In addition, the shorter bars before and after the Decision Bar are spaced either 100 feet or 200 feet apart, depending on the ALS type; the number of short bars the pilot can see can be used to determine flight visibility. Approaches with lower minimums use the more precise 100-foot spacing systems for more accurate identification of visibility. Several ALS configurations are recognized by the International Civil Aviation Organization. Approach lighting systems are of high-intensity. Many approach lighting systems are complemented by various on-runway light systems, such as Runway end identifier lights, Touchdown Zone Lights, High Intensity Runway Lights; the most common approach light system configurations include: MALSR: Medium-intensity Approach Lighting System with Runway Alignment Indicator Lights MALSF: Medium-intensity Approach Lighting System with Sequenced Flashing lights SALS: Short Approach Lighting System SSALS: Simplified Short Approach Lighting System SSALR: Simplified Short Approach Lighting System with Runway Alignment Indicator Lights SSALF: Simplified Short Approach Lighting System with Sequenced Flashing Lights ODALS: Omnidirectional Approach Lighting System ALSF-1: Approach Lighting System with Sequenced Flashing Lights configuration 1 ALSF-2: Approach Lighting System with Sequenced Flashing Lights configuration 2 CALVERT I/ICAO-1 HIALS: ICAO-compliant configuration 1 High Intensity Approach Lighting System CALVERT II/ICAO-2 HIALS: ICAO-compliant configuration 2 High Intensity Approach Lighting System LDIN: Lead-in lighting REIL: Runway End Identification Lights RAIL: Runway Alignment Indicator LightsIn configurations that include sequenced flashing lights, the lights are strobes mounted in front of the runway on its extended centerline.
These lights flash in sequence at a speed of two consecutive sequences per second, beginning with the light most distant from the runway and ending at the Decision Bar. RAIL are similar to sequenced flashing lights, except that they end where the white approach light bars begin. Sequenced flashing lights and RAI
Precision approach path indicator
A precision approach path indicator is a visual aid that provides guidance information to help a pilot acquire and maintain the correct approach to an airport or an aerodrome. It is located beside the runway 300 meters beyond the landing threshold of the runway; the precision approach path indicator system was first devised in 1974 by Tony Smith and David Johnson at the Royal Aircraft Establishment in Bedford, England. It took them a further two years to develop the technology. Smith and Johnson's work was honoured by a commendation from the RAE, a Fellowship from the Aeronautical Society, an award from the American Flight Safety Foundation, a Gold Medal from the British Guild of Air Pilots. Engineering firm Research Engineers were heavily involved in the project, having produced and supplied PAPI units for the first trials that were conducted; the same design is still in use today, in fact was used by NASA's Space Shuttle for its safe landing, for which Johnson was interviewed by UK local news media and TV.
The ratio of white to red lights seen is dependent on the angle of approach to the runway. Above the designated glide slope a pilot will observe more white lights than red. For the optimum approach angle the ratio of white to red lights will remain equal throughout, for most aircraft, the exceptions being the Boeing 747 and now retired Concorde. With the 747, because the cockpit is 20 feet behind the nose and much higher than other aircraft, the flight crew in a 747 will see one red and three white lights when they are on the glide slope; the aircrew of Concorde would see four white lights as the Concorde's approach angle was higher than traditional aircraft. The greater number of red lights visible compared with the number of white lights visible in the picture means that the aircraft is flying below the glideslope. To use the guidance information provided by the aid to follow the correct glide slope a pilot would manoeuvre the aircraft to obtain an equal number of red and white lights. Student pilots in initial training may use the mnemonic WHITE on WHITE - "Check your height" RED on WHITE – "You're all right" RED on RED – "You're dead" until they are used to the lights' meaning.
The PAPI is a light array positioned beside the runway. It consists of four equi-spaced light units color-coded to provide a visual indication of an aircraft's position relative to the designated glideslope for the runway. An abbreviated system consisting of two light units can be used for some categories of aircraft operations; the international standard for PAPI is published by the International Civil Aviation Organization in Aerodromes, Annex 14 to the Convention on International Civil Aviation, Volume 1, Chapter 5. National regulations adopt the standards and recommended practices published by ICAO. An earlier glideslope indicator system, the visual approach slope indicator is now obsolete and was deleted from Annex 14 in 1995; the VASI only provided guidance down to heights of 60 metres whereas PAPI provides guidance down to flare initiation. The PAPI is located on the left-hand side of the runway at right angles to the runway center line; the units are spaced 9 meters apart with the nearest unit 15 meters from the runway edge.
A PAPI can, be located on the right-hand side of the runway. At some locations PAPIs are installed on both sides of the runway but this level of provision is beyond the requirements of ICAO; the light characteristics of all light units are identical. In good visibility conditions the guidance information can be used at ranges up to 5 miles by day and night. At night the light bars can be seen at ranges of at least 20 miles; each light unit consists of red filters and lenses. Each light unit emits a high-intensity beam; the lower segment of the beam is red, the upper part is white. The transition between the two colours must take place over an angle not greater than three minutes of arc; this characteristic makes the color change conspicuous, a key feature of the PAPI signal. To form the PAPI guidance signal, the color transition boundaries of the four units are fixed at different angles; the lowest angle is used for the unit furthest from the runway, the highest for the unit nearest to the runway.
The designated glideslope is midway between the third light unit settings. Depending on the position of the aircraft relative to the specified angle of approach, the lights will appear either red or white to the pilot; the pilot will have reached the normal glidepath when there is an equal number of red and white lights. If an aircraft is beneath the glidepath, red lights will outnumber white. PAPI systems are available from airfield lighting manufacturers worldwide. PAPI is operated by air traffic control. If ATC services are not provided at an aerodrome, PAPI along with other airport lights may be activated by the pilot by keying the aircraft microphone with the aircraft's communication radio tuned to the CTAF or dedicated pilot controlled lighting frequency. A typical engineering design specification for a PAPI light unit is shown below: Optical construction: Preadjusted 2-lamp optical assembly. Anodized aluminium reflectors. Red color filters. Precision-ground lenses. Lamps and reflectors replaceable without recalibration.
2 x 200 W / 6,6 A prefocused halogen lamps, Pk30d base. Average lifetime 1000 hours at rated current.2008 saw the advent of new PAPI devices man
According to the International Civil Aviation Organization, a runway is a "defined rectangular area on a land aerodrome prepared for the landing and takeoff of aircraft". Runways may be a natural surface. In January 1919, aviation pioneer Orville Wright underlined the need for "distinctly marked and prepared landing places, the preparing of the surface of reasonably flat ground an expensive undertaking there would be a continuous expense for the upkeep." Runways are named by a number between 01 and 36, the magnetic azimuth of the runway's heading in decadegrees. This heading differs from true north by the local magnetic declination. A runway numbered 09 points east, runway 18 is south, runway 27 points west and runway 36 points to the north; when taking off from or landing on runway 09, a plane is heading around 90°. A runway can be used in both directions, is named for each direction separately: e.g. "runway 15" in one direction is "runway 33" when used in the other. The two numbers differ by 18.
For clarity in radio communications, each digit in the runway name is pronounced individually: runway one-five, runway three-three, etc.. A leading zero, for example in "runway zero-six" or "runway zero-one-left", is included for all ICAO and some U. S. military airports. However, most U. S. civil aviation airports drop the leading zero. This includes some military airfields such as Cairns Army Airfield; this American anomaly may lead to inconsistencies in conversations between American pilots and controllers in other countries. It is common in a country such as Canada for a controller to clear an incoming American aircraft to, for example, runway 04, the pilot read back the clearance as runway 4. In flight simulation programs those of American origin might apply U. S. usage to airports around the world. For example, runway 05 at Halifax will appear on the program as the single digit 5 rather than 05. If there is more than one runway pointing in the same direction, each runway is identified by appending left and right to the number to identify its position — for example, runways one-five-left, one-five-center, one-five-right.
Runway zero-three-left becomes runway two-one-right. 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. At large airports with four or more parallel runways some runway identifiers are shifted by 1 to avoid the ambiguity that would result with more than three parallel runways. For example, in Los Angeles, this system results in runways 6L, 6R, 7L, 7R though all four runways are parallel at 69°. At Dallas/Fort Worth International Airport, there are five parallel runways, named 17L, 17C, 17R, 18L, 18R, all oriented at a heading of 175.4°. An airport with only three parallel runways may use different runway identifiers, such as when a third parallel runway was opened at Phoenix Sky Harbor International Airport in 2000 to the south of existing 8R/26L — rather than confusingly becoming the "new" 8R/26L it was instead designated 7R/25L, with the former 8R/26L becoming 7L/25R and 8L/26R becoming 8/26.
Runway designations may change over time because Earth's magnetic lines drift on the surface and the magnetic direction changes. Depending on the airport location and how much drift occurs, it may be necessary to change the runway designation; as runways are designated with headings rounded to the nearest 10°, this affects some runways sooner than others. For example, if the magnetic heading of a runway is 233°, it is designated Runway 23. If the magnetic heading changes downwards by 5 degrees to 228°, the runway remains Runway 23. If on the other hand the original magnetic heading was 226°, the heading decreased by only 2 degrees to 224°, the runway becomes Runway 22; because magnetic drift itself is slow, runway designation changes are uncommon, not welcomed, as they require an accompanying change in aeronautical charts and descriptive documents. When runway designations do change at major airports, it is changed at night as taxiway signs need to be changed and the huge numbers at each end of the runway need to be repainted to the new runway designators.
In July 2009 for example, London Stansted Airport in the United Kingdom changed its runway designations from 05/23 to 04/22 during the night. For fixed-wing aircraft it is advantageous to perform takeoffs and landings into the wind to reduce takeoff or landing roll and reduce the ground speed needed to attain flying speed. Larger airports have several runways in different directions, so that one can be selected, most nearly aligned with the wind. Airports with one runway are constructed to be aligned with the prevailing wind. Compiling a wind rose is in fact one of the preliminary steps taken in constructing airport runways. Note that wind direction is given as the direction the wind is coming from: a plane taking off from runway 09 faces east, into an "east wind" blowing from 090°. Runway dimensions vary from as small as 245 m long and 8 m wide in s