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90-426: In air navigation or radio frequency identification , a flight transponder is an automated transceiver in an aircraft that emits a coded identifying signal in response to an interrogating received signal. In a communications satellite , a satellite transponder receives signals over a range of uplink frequencies, usually from a satellite ground station ; the transponder amplifies them, and re-transmits them on

180-500: A balloon is an unpowered aerostat , which remains aloft or floats due to its buoyancy . A balloon may be free, moving with the wind, or tethered to a fixed point. It is distinct from an airship , which is a powered aerostat that can propel itself through the air in a controlled manner. Many balloons have a basket , gondola , or capsule suspended beneath the main envelope for carrying people or equipment (including cameras and telescopes, and flight-control mechanisms). Aerostation

270-527: A balloon is unstable in high winds. Tethered balloons for use in windy conditions are often stabilised by aerodynamic shaping and connecting to the tether by a halter arrangement. These are called kite balloons . A kite balloon is distinct from a kytoon , which obtains a portion of its lift aerodynamically. Unmanned hot air balloons are mentioned in Chinese history. Zhuge Liang of the Shu Han kingdom, in

360-432: A different ETP. Commercial aircraft are not allowed to operate along a route that is out of range of a suitable place to land if an emergency such as an engine failure occurs. The ETP calculations serve as a planning strategy, so flight crews always have an 'out' in an emergency event, allowing a safe diversion to their chosen alternate. The final stage is to note which areas the route will pass through or over, and to make

450-781: A different set of downlink frequencies to receivers on Earth, often without changing the content of the received signal or signals. A communications satellite ’s channels are called transponders because each is a separate transceiver or repeater . With digital video data compression and multiplexing , several video and audio channels may travel through a single transponder on a single wideband carrier . Original analog video only has one channel per transponder, with subcarriers for audio and automatic transmission identification service ( ATIS ). Non-multiplexed radio stations can also travel in single channel per carrier (SCPC) mode, with multiple carriers (analog or digital) per transponder. This allows each station to transmit directly to

540-488: A distance of 27 miles (43 km), landing in the small town of Nesles-la-Vallée . The first Italian balloon ascent was made by Count Paolo Andreani and two other passengers in a balloon designed and constructed by the three Gerli brothers, on 25 February 1784. A public demonstration occurred in Brugherio a few days later, on 13 March 1784, when the vehicle flew to a height of 1,537 metres (5,043 ft) and

630-682: A distance of 8 kilometres (5.0 mi). On 28 March Andreani received a standing ovation at La Scala , and later a medal from Joseph II, Holy Roman Emperor . De Rozier, together with Joseph Proust , took part in a further flight on 23 June 1784, in a modified version of the Montgolfiers' first balloon christened La Marie-Antoinette after the Queen. They took off in front of the King of France and King Gustav III of Sweden. The balloon flew north at an altitude of approximately 3,000 metres, above

720-600: A few days. A superpressure balloon , in contrast, has a tough and inelastic envelope that is filled with light gas to pressure higher than that of the external atmosphere, and then sealed. The superpressure balloon cannot change size greatly, and so maintains a generally constant volume. The superpressure balloon maintains an altitude of constant density in the atmosphere, and can maintain flight until gas leakage gradually brings it down. Superpressure balloons offer flight endurance of months, rather than days. In fact, in typical operation an Earth-based superpressure balloon mission

810-401: A few exceptions, scientific balloon missions are unmanned. There are two types of light-gas balloons: zero-pressure and superpressure. Zero-pressure balloons are the traditional form of light-gas balloon. They are partially inflated with the light gas before launch, with the gas pressure the same both inside and outside the balloon. As the zero-pressure balloon rises, its gas expands to maintain

900-460: A height of 500 feet or so. The pilots, Jean-François Pilâtre de Rozier and François Laurent d'Arlandes , covered about 5.5 miles (8.9 km) in 25 minutes. On 1 December 1783, Professor Jacques Charles and the Robert brothers made the first gas balloon flight, also from Paris. Their hydrogen-filled balloon flew to almost 2,000 feet (600 m), stayed aloft for over 2 hours and covered

990-412: A lap they swipe or touch the receiver which is connected to a computer and log their lap time. NASCAR uses transponders and cable loops placed at numerous points around the track to determine the lineup during a caution period. This system replaced a dangerous race back to the start-finish line . Many modern automobiles have keys with transponders hidden inside the plastic head of the key. The user of

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1080-452: A line on the map to show the bearing from the beacon. By using a second beacon, two lines may be drawn to locate the aircraft at the intersection of the lines. This is called a cross-cut. Alternatively, if the track takes the flight directly overhead a beacon, the pilot can use the ADF instrument to maintain heading relative to the beacon, though "following the needle" is bad practice, especially in

1170-601: A long-distance flight such as crossing the English Channel , the aeronaut would need to make use of the differing wind directions at different altitudes. It would be essential therefore to have good control of altitude while still able to stay up for a long time. He developed a combination balloon having two gas bags, the Rozier balloon . The upper one held hydrogen and provided most of the steady lift. The lower one held hot air and could be quickly heated or cooled to provide

1260-400: A more sophisticated system, and is still the primary air navigation system established for aircraft flying under IFR in those countries with many navigational aids. In this system, a beacon emits a specially modulated signal which consists of two sine waves which are out of phase . The phase difference corresponds to the actual bearing relative to magnetic north (in some cases true north) that

1350-481: A note of all of the things to be done – which ATC units to contact, the appropriate frequencies, visual reporting points, and so on. It is also important to note which pressure setting regions will be entered, so that the pilot can ask for the QNH (air pressure) of those regions. Finally, the pilot should have in mind some alternative plans in case the route cannot be flown for some reason – unexpected weather conditions being

1440-500: A resident's car with simple transponder is parked in the vicinity, any vehicle can come up to the automated gate, triggering the gate interrogation signal , which may get an acceptable response from the resident's car. Such units properly installed might involve beamforming , unique transponders for each vehicle, or simply obliging vehicles to be stored away from the gate. Air navigation The basic principles of air navigation are identical to general navigation , which includes

1530-519: A result, differences in transponder functionality also might influence the functional description of related optical modules like transceivers and muxponders . Another type of transponder occurs in identification friend or foe (IFF) systems in military aviation and in air traffic control secondary surveillance radar (beacon radar) systems for general aviation and commercial aviation . Primary radar works best with large all-metal aircraft, but not so well on small, composite aircraft. Its range

1620-596: A room in Lisbon . On August 8, 1709, in Lisbon, Gusmão managed to lift a small balloon made of paper with hot air about four meters in front of king John V and the Portuguese court He also claimed to have built a balloon named Passarola ( Big bird ) and attempted to lift himself from Saint George Castle in Lisbon, landing about one kilometre away. However the claim of this feat remains uncertain, even though there

1710-416: A ship's radar screen. Sonar transponders operate under water and are used to measure distance and form the basis of underwater location marking, position tracking and navigation . Electronic toll collection systems such as E-ZPass in the eastern United States use RFID transponders to identify vehicles. Transponders are used in races for lap timing. A cable loop is dug into the race circuit near to

1800-598: A short, non-fiction story, published in 1852, about being stranded aboard a hydrogen balloon. The earliest successful balloon flight recorded in Australia was by William Dean in 1858. His balloon was gas-filled and travelled 30 km with two people aboard. On 5 January 1870, T. Gale, made an ascent from the Domain in Sydney. His balloon was 17 metres in length by 31 metres in circumference and his ascent, with him seated on

1890-407: A single beacon alone. For convenience, some VOR stations also transmit local weather information which the pilot can listen in to, perhaps generated by an Automated Surface Observing System . A VOR which is co-located with a DME is usually a component of a TACAN . Prior to the advent of GNSS , Celestial Navigation was also used by trained navigators on military bombers and transport aircraft in

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1980-481: Is a 'wind-star' maneuver and, with no winds aloft, will place him back on his original track with his trip time increased by the length of one diversion leg. Another reason for not relying on the magnetic compass during flight, apart from calibrating the Heading indicator from time to time, is because magnetic compasses are subject to errors caused by flight conditions and other internal and external interferences on

2070-470: Is a fabric envelope filled with a gas that is lighter than the surrounding atmosphere . As the entire balloon is less dense than its surroundings, it rises, taking along with it a basket, attached underneath, which carries passengers or payload. Although a balloon has no propulsion system, a degree of directional control is possible by making the balloon rise or sink in altitude to find favorable wind directions. There are three main types of balloons: Both

2160-404: Is also limited by terrain and rain or snow and also detects unwanted objects such as automobiles, hills and trees. Furthermore, it cannot always estimate the altitude of an aircraft. Secondary radar overcomes these limitations but it depends on a transponder in the aircraft to respond to interrogations from the ground station to make the plane more visible. Depending on the type of interrogation,

2250-434: Is an obsolete term referring to ballooning and the construction, operation, and navigation of lighter-than-air vehicles. Tiberius Cavallo 's The History and Practice of Aerostation was published in 1785. Other books were published on the subject including by Monck Mason . Dramatist Frederick Pilon wrote a play with aerostation as its title. A balloon is conceptually the simplest of all flying machines. The balloon

2340-516: Is closer to continue. Similarly, the Equal time point, referred to as the ETP (also critical point), is the point in the flight where it would take the same time to continue flying straight, or track back to the departure aerodrome. The ETP is not dependent on fuel, but wind, giving a change in ground speed out from, and back to the departure aerodrome. In Nil wind conditions, the ETP is located halfway between

2430-455: Is deciding where one wishes to go. A private pilot planning a flight under VFR will usually use an aeronautical chart of the area which is published specifically for the use of pilots. This map will depict controlled airspace , radio navigation aids and airfields prominently, as well as hazards to flying such as mountains, tall radio masts, etc. It also includes sufficient ground detail – towns, roads, wooded areas – to aid visual navigation. In

2520-410: Is ended by a command from ground control to open the envelope, rather than by natural leakage of gas. High-altitude balloons are used as high flying vessels to carry scientific instruments (like weather balloons ), or reach near-space altitudes to take footage or photos of the earth. These balloons can fly over 100,000 feet (30.5 km) into the air, and are designed to burst at a set altitude where

2610-412: Is especially true if flying in the dark or over featureless terrain. This means that the pilot must stick to the calculated headings, heights and speeds as accurately as possible, unless flying under visual flight rules . The visual pilot must regularly compare the ground with the map, ( pilotage ) to ensure that the track is being followed although adjustments are generally calculated and planned. Usually,

2700-405: Is greater than the weight of the balloon containing it, it will lift the balloon upwards. A hot air balloon can only stay up while it has fuel for its burner, to keep the air hot enough. The Montgolfiers' early hot air balloons used a solid-fuel brazier which proved less practical than the hydrogen balloons that had followed almost immediately, and hot air ballooning soon died out. In the 1950s,

2790-412: Is mandatory in controlled airspace in many countries. Some countries have also required, or are moving toward requiring, that all aircraft be equipped with Mode S, even in uncontrolled airspace . However, in the field of general aviation there have been objections to these moves, because of the cost, size, limited benefit to the users in uncontrolled airspace, and, in the case of balloons and gliders ,

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2880-466: Is not as easy as it might appear, unless there is no wind at all—a very rare occurrence. The pilot must adjust heading to compensate for the wind , in order to follow the ground track. Initially the pilot will calculate headings to fly for each leg of the trip prior to departure, using the forecast wind directions and speeds supplied by the meteorological authorities for the purpose . These figures are generally accurate and updated several times per day, but

2970-597: Is record of this flight in the source used by the FAI the exact distance and conditions of the flight are not confirmed. Following Henry Cavendish 's 1766 work on hydrogen , Joseph Black proposed that a balloon filled with hydrogen would be able to rise in the air. The first recorded manned flight was made in a hot air balloon built by the Montgolfier brothers on 21 November 1783. The flight started in Paris and reached

3060-685: The Austrian Netherlands , Germany, the Netherlands and Poland . His hydrogen filled balloon took off from a prison yard in Philadelphia , Pennsylvania. The flight reached 5,800 feet (1,770 m) and landed in Gloucester County, New Jersey . President George Washington was among the guests observing the takeoff. Sophie Blanchard , married to Jean-Pierre, was the first woman to pilot her own balloon and

3150-865: The Brazilian Army . Balloons were used by the British Royal Engineers in 1885 for reconnaissance and observation purposes during the Bechuanaland Expedition and the Sudan Expedition . Although experiments in Britain had been conducted as early as 1863, a School of Ballooning was not established at Chatham, Medway, Kent until 1888. During the Anglo-Boer War (1899–1902), use was made of observation balloons. A 11,500 cubic feet (330 m ) balloon

3240-635: The GA pilot. Recently, many airports include GNSS instrument approaches. GNSS approaches consist of either overlays to existing precision and non-precision approaches or stand-alone GNSS approaches. Approaches having the lowest decision heights generally require that GNSS be augmented by a second system—e.g., the FAA's Wide Area Augmentation System (WAAS). Civilian flight navigators (a mostly redundant aircrew position, also called 'air navigator' or 'flight navigator'), were employed on older aircraft, typically between

3330-715: The Three Kingdoms era (220–280 AD) used airborne lanterns for military signaling. These lanterns are known as Kongming lanterns ( Kǒngmíng dēng 孔明灯 ). The Mongolian army learned of the Kongming lantern from the Chinese and used it in Battle of Legnica during the Mongol invasion of Poland. In 1709 the Brazilian-Portuguese cleric Bartolomeu de Gusmão made a balloon filled with heated air rise inside

3420-553: The UK , the CAA publishes a series of maps covering the whole of the UK at various scales, updated annually. The information is also updated in the notices to airmen , or NOTAMs. The pilot will choose a route, taking care to avoid controlled airspace that is not permitted for the flight, restricted areas, danger areas and so on. The chosen route is plotted on the map, and the lines drawn are called

3510-470: The lowest safe altitude (LSALT), bearings (in both directions), and distance marked for each route. IFR pilots may fly on other routes but they then must perform all such calculations themselves; the LSALT calculation is the most difficult. The pilot then needs to look at the weather and minimum specifications for landing at the destination airport and the alternate requirements. Pilots must also comply with all

3600-402: The track . The aim of all subsequent navigation is to follow the chosen track as accurately as possible. Occasionally, the pilot may elect on one leg to follow a clearly visible feature on the ground such as a railway track, river, highway, or coast. When an aircraft is in flight, it is moving relative to the body of air through which it is flying; therefore maintaining an accurate ground track

3690-511: The DI periodically. The compass itself will only show a steady reading when the aircraft has been in straight and level flight long enough to allow it to settle. Should the pilot be unable to complete a leg – for example bad weather arises, or the visibility falls below the minima permitted by the pilot's license, the pilot must divert to another route. Since this is an unplanned leg, the pilot must be able to mentally calculate suitable headings to give

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3780-699: The French army; however, given the logistical problems linked with the production of hydrogen on the battlefield (it required constructing ovens and pouring water on white-hot iron), the corps was disbanded in 1799. The first major use of balloons in the military occurred during the American Civil War with the Union Army Balloon Corps established in 1861. During the Paraguayan War (1864–70), observation balloons were used by

3870-456: The PNR, is the point on a flight at which a plane has just enough fuel, plus any mandatory reserve, to return to the airfield from which it departed. Beyond this point that option is closed, and the plane must proceed to some other destination. Alternatively, with respect to a large region without airfields, e.g. an ocean, it can mean the point before which it is closer to turn around and after which it

3960-709: The United States and Canada. In Operation Outward the British used balloons to carry incendiaries to Nazi Germany . During 2018, incendiary balloons and kites were launched from Gaza at Israel, burning some 12,000 dunams (3,000 acres) in Israel. Large helium balloons are used by the South Korean government and private activists advocating freedom in North Korea . They float hundreds of kilometers across

4050-493: The aggregate navigation aids present within the applicable airspace. Once these determinations have been made, the operator develops a route that is the most time and fuel efficient while respecting all applicable safety concerns—thereby maximizing both the aircraft's and the airspace's overall performance capabilities. Under the PBN approach, technologies evolve over time (e.g., ground beacons become satellite beacons) without requiring

4140-471: The amount of fuel they can carry; a surface vehicle can usually get lost, run out of fuel, then simply await rescue. There is no in-flight rescue for most aircraft. Additionally, collisions with obstructions are usually fatal. Therefore, constant awareness of position is critical for aircraft pilots. The techniques used for navigation in the air will depend on whether the aircraft is flying under visual flight rules (VFR) or instrument flight rules (IFR). In

4230-400: The border carrying news from the outside world, illegal radios, foreign currency and gifts of personal hygiene supplies. A North Korean military official has described it as "psychological warfare" and threatened to attack South Korea if their release continued. Ed Yost redesigned the hot air balloon in the late 1950s using rip-stop nylon fabrics and high-powered propane burners to create

4320-543: The car may not even be aware that the transponder is there, because there are no buttons to press. When a key is inserted into the ignition lock cylinder and turned, the car's computer sends a signal to the transponder. Unless the transponder replies with a valid code, the computer will not allow the engine to be started. Transponder keys have no battery; they are energized by the signal itself. Transponders may also be used by residents to enter their gated communities . However, having more than one transponder causes problems. If

4410-522: The clouds, travelling 52 km in 45 minutes before cold and turbulence forced them to descend past Luzarches , between Coye et Orry-la-Ville , near the Chantilly forest. The first balloon ascent in Britain was made by James Tytler on 25 August 1784 at Edinburgh , Scotland, in a hot air balloon . The first aircraft disaster occurred in May 1785 when the town of Tullamore , County Offaly , Ireland

4500-436: The convenience and low cost of bottled gas burners led to a revival of hot air ballooning for sport and leisure. The height or altitude of a hot air balloon is controlled by turning the burner up or down as needed, unlike a gas balloon where ballast weights are often carried so that they can be dropped if the balloon gets too low, and in order to land some lifting gas must be vented through a valve. A man-carrying balloon using

4590-424: The desired new track. Using the flight computer in flight is usually impractical, so mental techniques to give rough and ready results are used. The wind is usually allowed for by assuming that sine A = A, for angles less than 60° (when expressed in terms of a fraction of 60° – e.g. 30° is 1/2 of 60°, and sine 30° = 0.5), which is adequately accurate. A method for computing this mentally is the clock code . However

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4680-468: The end of the leg. This is also a point to reassess the estimated time for the leg. A good pilot will become adept at applying a variety of techniques to stay on track. While the compass is the primary instrument used to determine one's heading, pilots will usually refer instead to the direction indicator (DI), a gyroscopically driven device which is much more stable than a compass. The compass reading will be used to correct for any drift ( precession ) of

4770-552: The event of all electronic navigational aids being turned off in time of war. Originally navigators used an astrodome and regular sextant but the more streamlined periscopic sextant was used from the 1940s to the 1990s. From the 1970s airliners used inertial navigation systems , especially on inter-continental routes, until the shooting down of Korean Air Lines Flight 007 in 1983 prompted the US government to make GPS available for civilian use. Finally, an aircraft may be supervised from

4860-409: The first passenger flight was 19 September 1783, carrying a sheep, a duck, and a rooster. The first tethered manned balloon flight was by a larger Montgolfier balloon, probably on 15 October 1783. The first free balloon flight was by the same Montgolfier balloon on 21 November 1783. When heated, air expands, so a given volume of space contains less air. This makes it lighter and, if its lifting power

4950-633: The first woman to adopt ballooning as a career. On 29 September 1804, Abraham Hopman became the first Dutchman to make a successful balloon flight in the Netherlands . Gas balloons became the most common type from the 1790s until the 1960s. The French military observation balloon L'Intrépide of 1795 is the oldest preserved aircraft in Europe; it is on display in the Heeresgeschichtliches Museum in Vienna. Jules Verne wrote

5040-538: The ground using surveillance information from e.g. radar or multilateration . ATC can then feed back information to the pilot to help establish position, or can actually tell the pilot the position of the aircraft, depending on the level of ATC service the pilot is receiving. The use of GNSS in aircraft is becoming increasingly common. GNSS provides very precise aircraft position, altitude, heading and ground speed information. GNSS makes navigation precision once reserved to large RNAV -equipped aircraft available to

5130-473: The hot air, or Montgolfière, balloon and the gas balloon are still in common use. Montgolfière balloons are relatively inexpensive, as they do not require high-grade materials for their envelopes, and they are popular for balloonist sport activity. The first balloon which carried passengers used hot air to obtain buoyancy and was built by the brothers Joseph and Etienne Montgolfier in Annonay , France in 1783:

5220-470: The late-1910s and the 1970s. The crew member, occasionally two navigation crew members for some flights, was responsible for the trip navigation, including its dead reckoning and celestial navigation . This was especially essential when trips were flown over oceans or other large bodies of water, where radio navigation aids were not originally available. (satellite coverage is now provided worldwide). As sophisticated electronic and GNSS systems came online,

5310-476: The latter case, the pilot will navigate exclusively using instruments and radio navigation aids such as beacons, or as directed under radar control by air traffic control . In the former case, a pilot will largely navigate using " dead reckoning " combined with visual observations (known as pilotage ), with reference to appropriate maps. This may be supplemented using radio navigation aids or satellite based positioning systems . The first step in navigation

5400-458: The lifting gas, and several designs have successfully undertaken long-distance flights. As an alternative to free flight, a balloon may be tethered to allow reliable take off and landing at the same location. Some of the earliest balloon flights were tethered for safety, and since then balloons have been tethered for many purposes, including military observation and aerial barrage, meteorological and commercial uses. The natural spherical shape of

5490-537: The lifting power of hydrogen, which had to be specially manufactured. In 1836 Green made an almost 500 mile long-distance flight from London, England to Weilberg in Germany. The first military use of a balloon was at the Battle of Fleurus in 1794, when L'Entreprenant was used by the French Aerostatic Corps to watch the movements of the enemy. On 2 April 1794, an aeronauts corps was created in

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5580-519: The light gas hydrogen for buoyancy was made by Professor Jacques Charles and flown less than a month after the Montgolfier flight, on 1 December 1783. Gas balloons have greater lift for a given volume, so they do not need to be so large, and they can also stay up for much longer than hot air, so gas balloons dominated ballooning for the next 200 years. In the 19th century, it was common to use manufactured town gas (coal gas) to fill balloons; this

5670-444: The magnet system. Many GA aircraft are fitted with a variety of navigation aids, such as Automatic direction finder (ADF), inertial navigation , compasses , radar navigation , VHF omnidirectional range (VOR) and Global navigation satellite system (GNSS). ADF uses non-directional beacons (NDBs) on the ground to drive a display which shows the direction of the beacon from the aircraft. The pilot may use this bearing to draw

5760-465: The most common. At times the pilot may be required to file a flight plan for an alternate destination and to carry adequate fuel for this. The more work a pilot can do on the ground prior to departure, the easier it will be in the air. Instrument flight rules (IFR) navigation is similar to visual flight rules (VFR) flight planning except that the task is generally made simpler by the use of special charts that show IFR routes from beacon to beacon with

5850-408: The navigator's position in commercial aviation (but not necessarily military aviation) became redundant. (Some countries task their air forces to fly without navigation aids during wartime , thus still requiring a navigator's position). Most civilian air navigators were retired or made redundant by the early 1980s. Citations Bibliography Balloon (aeronautics) In aeronautics ,

5940-455: The navigator's position was discontinued and its function was assumed by dual-licensed pilot-navigators, and still later by the flight's primary pilots (Captain and First Officer), resulting in a downsizing in the number of aircrew positions for commercial flights. As the installation of electronic navigation systems into the Captain's and FO's instrument panels was relatively straight forward,

6030-635: The netting, took him about a mile before he landed in Glebe. Henri Giffard also developed a tethered balloon for passengers in 1878 in the Tuileries Garden in Paris. The first tethered balloon in modern times was made in France at Chantilly Castle in 1994 by Aerophile SA . Ballooning developed as a leisure activity. It was given a significant boost when Charles Green discovered that readily-available coal gas , then coming into urban use, gave half

6120-442: The parachute will deploy to safely carry the payload back to earth. Cluster ballooning uses many smaller gas-filled balloons for flight. Early hot air balloons could not stay up for very long because they used a lot of fuel, while early hydrogen balloons were difficult to take higher or lower as desired because the aeronaut could only vent the gas or drop off ballast a limited number of times. Pilâtre de Rozier realised that for

6210-426: The pilot must also allow for this, called the magnetic variation (or declination). The variation that applies locally is also shown on the flight map. Once the pilot has calculated the actual headings required, the next step is to calculate the flight times for each leg. This is necessary to perform accurate dead reckoning . The pilot also needs to take into account the slower initial airspeed during climb to calculate

6300-418: The pilot must be extra vigilant when flying diversions to maintain awareness of position. Some diversions can be temporary – for example to skirt around a local storm cloud. In such cases, the pilot can turn 60 degrees away his desired heading for a given period of time. Once clear of the storm, he can then turn back in the opposite direction 120 degrees, and fly this heading for the same length of time. This

6390-435: The pilot will fly for some time as planned to a point where features on the ground are easily recognised. If the wind is different from that expected, the pilot must adjust heading accordingly, but this is not done by guesswork, but by mental calculation – often using the 1 in 60 rule . For example, a two degree error at the halfway stage can be corrected by adjusting heading by four degrees the other way to arrive in position at

6480-465: The power requirements during long flights. Transponders are used on some military aircraft to ensure ground personnel can verify the functionality of a missile’s flight termination system prior to launch. Such radar-enhancing transponders are needed as the enclosed weapon bays on modern aircraft interfere with prelaunch, flight termination system verification performed by range safety personnel during training test launches. The transponders re-radiate

6570-399: The presence of a strong cross wind – the pilot's actual track will spiral in towards the beacon, not what was intended. NDBs also can give erroneous readings because they use very long wavelengths , which are easily bent and reflected by ground features and the atmosphere. NDBs continue to be used as a common form of navigation in some countries with relatively few navigational aids. VOR is

6660-599: The process of planning, recording, and controlling the movement of a craft from one place to another. Successful air navigation involves piloting an aircraft from place to place without getting lost, not breaking the laws applying to aircraft, or endangering the safety of those on board or on the ground . Air navigation differs from the navigation of surface craft in several ways; Aircraft travel at relatively high speeds, leaving less time to calculate their position en route. Aircraft normally cannot stop in mid-air to ascertain their position at leisure. Aircraft are safety-limited by

6750-873: The purpose of igniting the hydrogen. The Aeronaut Badge was established by the United States Army in World War I to denote service members who were qualified balloon pilots. Observation balloons were retained well after the Great War, being used in the Russo-Finnish Wars, the Winter War of 1939–40, and the Continuation War of 1941–45. During World War II the Japanese launched thousands of hydrogen " fire balloons " against

6840-442: The receiver is from the station. The upshot is that the receiver can determine with certainty the exact bearing from the station. Again, a cross-cut is used to pinpoint the location. Many VOR stations also have additional equipment called DME ( distance measuring equipment ) which will allow a suitable receiver to determine the exact distance from the station. Together with the bearing, this allows an exact position to be determined from

6930-466: The rules including their legal ability to use a particular instrument approach depending on how recently they last performed one. In recent years, strict beacon-to-beacon flight paths have started to be replaced by routes derived through performance-based navigation (PBN) techniques. When operators develop flight plans for their aircraft, the PBN approach encourages them to assess the overall accuracy, integrity, availability, continuity, and functionality of

7020-530: The satellite, rather than paying for a whole transponder, or using landlines to send it to an earth station for multiplexing with other stations. In fiber-optic communications , a transponder is the element that sends and receives the optical signal from a fiber . A transponder is typically characterized by its data rate and the maximum distance the signal can travel. The term "transponder" can apply to different items with important functional differences, mentioned across academic and commercial literature: As

7110-847: The signals allowing for much longer communication distances. The International Maritime Organization 's International Convention for the Safety of Life at Sea (SOLAS) requires the Automatic Identification System (AIS) to be fitted aboard international voyaging ships with 300 or more  gross tonnage  (GT), and all passenger ships regardless of size. AIS transmitters/receivers are generally called transponders , but they generally transmit autonomously, although coast stations can interrogate class B transponders on smaller vessels for additional information. In addition, navigational aids often have transponders called RACON (radar beacons) designed to make them stand out on

7200-435: The start/finish line. Each individual runner or car has an active transponder with a unique ID code. When the individual passes the start/finish line, the lap time and the racing position is shown on the score board. Passive and active RFID systems are used in motor sports , and off-road events such as Enduro and Hare and Hounds racing, the riders have a transponder on their person, normally on their arm. When they complete

7290-444: The time to top of climb. It is also helpful to calculate the top of descent, or the point at which the pilot would plan to commence the descent for landing. The flight time will depend on both the desired cruising speed of the aircraft, and the wind – a tailwind will shorten flight times, a headwind will increase them. The flight computer has scales to help pilots compute these easily. The point of no return , sometimes referred to as

7380-467: The transponder sends back a transponder code (or "squawk code", Mode A) or altitude information (Mode C) to help air traffic controllers to identify the aircraft and to maintain separation between planes. Another mode called Mode S (Mode Select) is designed to help avoiding over-interrogation of the transponder (having many radars in busy areas) and to allow automatic collision avoidance. Mode S transponders are backward compatible with Modes A and C. Mode S

7470-607: The two aerodromes, but in reality it is shifted depending on the windspeed and direction. The aircraft that is flying across the Ocean for example, would be required to calculate ETPs for one engine inoperative, depressurization, and a normal ETP; all of which could actually be different points along the route. For example, in one engine inoperative and depressurization situations the aircraft would be forced to lower operational altitudes, which would affect its fuel consumption, cruise speed and ground speed. Each situation therefore would have

7560-410: The underlying aircraft operation to be recalculated. Also, navigation specifications used to assess the sensors and equipment that are available in an airspace can be cataloged and shared to inform equipment upgrade decisions and the ongoing harmonization of the world's various air navigation systems. Once in flight, the pilot must take pains to stick to plan, otherwise getting lost is all too easy. This

7650-475: The unpredictable nature of the weather means that the pilot must be prepared to make further adjustments in flight. A general aviation (GA) pilot will often make use of either a flight computer – a type of slide rule – or a purpose-designed electronic navigational computer to calculate initial headings. The primary instrument of navigation is the magnetic compass . The needle or card aligns itself to magnetic north , which does not coincide with true north , so

7740-614: The varying lift for good altitude control. In 1785 Pilâtre de Rozier took off in an attempt to fly across the Channel, but shortly into the flight the hydrogen gas bag caught fire and de Rozier did not survive the ensuing accident. This earned de Rozier the title "The First to Fly and the First to Die". It wasn't until the 1980s that technology was developed to allow safe operation of the Rozier type, for example by using non-flammable helium as

7830-432: The zero pressure difference, and the balloon's envelope swells. At night, the gas in a zero-pressure balloon cools and contracts, causing the balloon to sink. A zero-pressure balloon can only maintain altitude by releasing gas when it goes too high, where the expanding gas can threaten to rupture the envelope, or releasing ballast when it sinks too low. Loss of gas and ballast limits the endurance of zero-pressure balloons to

7920-553: Was kept inflated for 22 days and marched 165 miles into the Transvaal with the British forces. Hydrogen-filled balloons were widely used during World War I (1914–1918) to detect enemy troop movements and to direct artillery fire. Observers phoned their reports to officers on the ground who then relayed the information to those who needed it. Balloons were frequently targets of opposing aircraft. Planes assigned to attack enemy balloons were often equipped with incendiary bullets , for

8010-411: Was not as light as pure hydrogen gas, having about half the lifting power, but it was much cheaper and readily available. Light gas balloons are predominant in scientific applications, as they are capable of reaching much higher altitudes for much longer periods of time. They are generally filled with helium. Although hydrogen has more lifting power, it is explosive in an atmosphere rich in oxygen . With

8100-493: Was seriously damaged when the crash of a balloon resulted in a fire that burned down about 100 houses, making the town home to the world's first aviation disaster . To this day, the town shield depicts a phoenix rising from the ashes. Jean-Pierre Blanchard went on to make the first manned flight of a balloon in America on 9 January 1793, after touring Europe to set the record for the first balloon flight in countries including

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