General Aviation represents the'private transport' and recreational flying component of aviation. General aviation is the name or term given to all civil aviation aircraft operations with the exception of commercial air transport or aerial work, they are flight activities not involving commercial air transportation of passengers, cargo or mail for remuneration or hire, or an aerial work operation such as agriculture, photography, surveying and patrol, search and rescue, aerial advertisement, etc. It covers certain commercial and private flights that can be carried out under both visual flight and instrument flight rules, such as light aircraft and private jets or helicopters. General aviation thus represents the'private transport' component of aviation; the International Civil Aviation Organization defines civil aviation aircraft operations in three categories: General Aviation, Aerial Work and Commercial Air Transport. The International Council of Aircraft Owner and Pilot Associations includes the following definitions for General Aviation aircraft activities: Corporate Aviation: Company own-use flight operations Fractional Ownership Operations: aircraft operated by a specialized company on behalf of two or more co-owners Business Aviation: self-flown for business purposes Personal/Private Travel: travel for personal reasons/personal transport Air Tourism: self-flown incoming/outgoing tourism Recreational Flying: powered/powerless leisure flying activities Air Sports: Aerobatics, Air Races, Rallies etc.
In 2003 the European Aviation Safety Agency was established as the central EU regulator, taking over responsibility for legislating airworthiness and environmental regulation from the national authorities. Of the 21,000 civil aircraft registered in the UK, 96 percent are engaged in GA operations, annually the GA fleet accounts for between 1.25 and 1.35 million hours flown. There are 28,000 Private Pilot Licence holders, 10,000 certified glider pilots; some of the 19,000 pilots who hold professional licences are engaged in GA activities. GA operates from more than 1,800 airports and landing sites or aerodromes, ranging in size from large regional airports to farm strips. GA is regulated by the Civil Aviation Authority, although regulatory powers are being transferred to the European Aviation Safety Agency; the main focus is on standards of airworthiness and pilot licensing, the objective is to promote high standards of safety. General aviation is popular in North America, with over 6,300 airports available for public use by pilots of general aviation aircraft.
In comparison, scheduled flights operate from around 560 airports in the U. S. According to the U. S. Aircraft Owners and Pilots Association, general aviation provides more than one percent of the United States' GDP, accounting for 1.3 million jobs in professional services and manufacturing. Most countries have authorities that oversee all civil aviation, including general aviation, adhering to the standardized codes of the International Civil Aviation Organization. Examples include the Federal Aviation Administration in the United States, the Civil Aviation Authority in the United Kingdom, Civil Aviation Authority of Zimbabwe in Zimbabwe, the Luftfahrt-Bundesamt in Germany, the Bundesamt für Zivilluftfahrt in Switzerland, Transport Canada in Canada, the Civil Aviation Safety Authority in Australia, the Directorate General of Civil Aviation in India and Iran Civil Aviation Organization in Iran. Aviation accident rate statistics are estimates. According to the U. S. National Transportation Safety Board, in 2005 general aviation in the United States suffered 1.31 fatal accidents for every 100,000 hours of flying in that country, compared to 0.016 for scheduled airline flights.
In Canada, recreational flying accounted for 0.7 fatal accidents for every 1000 aircraft, while air taxi accounted for 1.1 fatal accidents for every 100,000 hours. More experienced GA pilots appear safer, although the relations between flight hours, accident frequency, accident rates are complex and difficult to assess. Environmental impact of aviation List of current production certified light aircraftAssociationsAircraft Owners and Pilots Association Canadian Owners and Pilots Association Experimental Aircraft Association General Aviation Manufacturers Association National Business Aviation Association International Aircraft Owners and Pilots Associations European General Aviation Safety Team "No Plane No Gain" website about business aviation Save-GA.org website concerned with General Aviation in the United States "GA price index". Flight International. 13 Oct 1979
Nav Canada is a run, not-for-profit corporation that owns and operates Canada's civil air navigation system. It was established in accordance with the Civil Air Navigation Services Commercialization Act; the company employs 1,900 air traffic controllers, 650 flight service specialists and 700 technologists. It has been responsible for the safe and expeditious flow of air traffic in Canadian airspace since November 1, 1996 when the government transferred the ANS from Transport Canada to Nav Canada; as part of the transfer, or privatization, Nav Canada paid the government CA$1.5 billion. Nav Canada manages 12 million aircraft movements a year for 40,000 customers in over 18 million square kilometres, making it the world’s second-largest air navigation service provider by traffic volume. Nav Canada, which operates independently of any government funding, is headquartered in Ottawa, Ontario, it is only allowed to be funded by service charges to aircraft operators. Nav Canada's operations consist of various sites across the country.
These include: About 1,400 ground-based navigation aids 55 flight service stations 8 flight information centres, one each in: Kamloops – most of British Columbia Edmonton – all of Alberta and northeastern BC Winnipeg – northwestern Ontario, all of Manitoba and Saskatchewan London – most of Ontario North Bay – all of Nunavut and Northwest Territories, most of the Arctic waters Quebec City – all of Quebec, southwestern Labrador, tip of eastern Ontario, northern New Brunswick Halifax – most of New Brunswick, Nova Scotia, Prince Edward Island, most of Newfoundland and Labrador Whitehorse – northwestern British Columbia and all of Yukon 41 control towers 46 radar sites and 15 automatic dependent surveillance-broadcast ground sites 7 Area Control Centres, one each in: Vancouver – Surrey, BC Edmonton – Edmonton International Airport Winnipeg – Winnipeg-James Armstrong Richardson International Airport Toronto Centre – Toronto-Pearson International Airport Montreal Centre – Montreal-Trudeau International Airport Moncton – Riverview, New Brunswick Gander – Gander International Airport North Atlantic Oceanic control centre: Gander ControlNav Canada has three other facilities: National Operations Centre: Ottawa Technical Systems Centre: Ottawa The Nav Centre – 1950 Montreal Road in Cornwall, Ontario As a non-share capital corporation, Nav Canada has no shareholders.
The company is governed by a 15-member board of directors representing the four stakeholder groups that founded Nav Canada. The four stakeholders elect 10 members as follows: These 10 directors elect four independent directors, with no ties to the stakeholder groups; those 14 directors appoint the president and chief executive officer who becomes the 15th board member. This structure ensures that the interests of individual stakeholders do not predominate and no member group could exert undue influence over the remainder of the board. To further ensure that the interests of Nav Canada are served, these board members cannot be active employees or members of airlines, unions, or government; the company was formed on November 1, 1996 when the government sold the country's air navigation services from Transport Canada to the new not-for-profit private entity for CAD$1.5 billion. The company was formed in response to a number of issues with Transport Canada's operation of air traffic control and air navigation facilities.
While TC's safety record and operational staff were rated its infrastructure was old and in need of serious updating at a time of government restraint. This resulted in system delays for airlines and costs that were exceeding the airline ticket tax, a directed tax, supposed to fund the system; the climate of government wage freezes resulted in staff shortages of air traffic controllers that were hard to address within a government department. Having TC as the service provider, the regulator and inspector was a conflict of interest. Pressure from the airlines on the government mounted for a solution to the problem, hurting the air industry's bottom line. A number of solutions were considered, including forming a crown corporation, but rejected in favour of outright privatization, the new company being formed as a non-share-capital not-for-profit, run by a board of directors who were appointed and now elected; the company's revenue is predominately from service fees charged to aircraft operators which amount to about CAD$1.2B annually.
Nav Canada raises revenues from developing and selling technology and related services to other air navigation service providers around the world. It has some smaller sources of income, such as conducting maintenance work for other ANS providers and rentals from the Nav Centre in Cornwall, Ontario. To address the old infrastructure it purchased from the Canadian government the company has carried out projects such as implementing a wide area multilateration system, replacing 95 Instrument Landing System installations with new equipment, new control towers in Toronto and Calgary, modernizing the Vancouver Area Control Centre and building a new logistics centre Nav Canada felt the impact of the late-2000s recession in two ways: losses in its investments in third party sponsored asset-backed commercial paper and falling revenues due to reduced air traffic levels. In the summer of 2007 the company held $368 million in ABCP. On 12 January 2009 final Ontario Superior Court of Justice approval was granted to restructure the third party ABCP notes.
The company expects that the non-credit related fai
Weather forecasting is the application of science and technology to predict the conditions of the atmosphere for a given location and time. People have attempted to predict the weather informally for millennia and formally since the 19th century. Weather forecasts are made by collecting quantitative data about the current state of the atmosphere at a given place and using meteorology to project how the atmosphere will change. Once calculated by hand based upon changes in barometric pressure, current weather conditions, sky condition or cloud cover, weather forecasting now relies on computer-based models that take many atmospheric factors into account. Human input is still required to pick the best possible forecast model to base the forecast upon, which involves pattern recognition skills, knowledge of model performance, knowledge of model biases; the inaccuracy of forecasting is due to the chaotic nature of the atmosphere, the massive computational power required to solve the equations that describe the atmosphere, the error involved in measuring the initial conditions, an incomplete understanding of atmospheric processes.
Hence, forecasts become less accurate as the difference between current time and the time for which the forecast is being made increases. The use of ensembles and model consensus help narrow the error and pick the most outcome. There are a variety of end uses to weather forecasts. Weather warnings are important forecasts because they are used to protect property. Forecasts based on temperature and precipitation are important to agriculture, therefore to traders within commodity markets. Temperature forecasts are used by utility companies to estimate demand over coming days. On an everyday basis, people use weather forecasts to determine. Since outdoor activities are curtailed by heavy rain and wind chill, forecasts can be used to plan activities around these events, to plan ahead and survive them. In 2009, the US spent $5.1 billion on weather forecasting. For millennia people have tried to forecast the weather. In 650 BC, the Babylonians predicted the weather from cloud patterns as well as astrology.
In about 350 BC, Aristotle described weather patterns in Meteorologica. Theophrastus compiled a book on weather forecasting, called the Book of Signs. Chinese weather prediction lore extends at least as far back as 300 BC, around the same time ancient Indian astronomers developed weather-prediction methods. In New Testament times, Christ himself referred to deciphering and understanding local weather patterns, by saying, "When evening comes, you say,'It will be fair weather, for the sky is red', in the morning,'Today it will be stormy, for the sky is red and overcast.' You know how to interpret the appearance of the sky, but you cannot interpret the signs of the times."In 904 AD, Ibn Wahshiyya's Nabatean Agriculture, translated into Arabic from an earlier Aramaic work, discussed the weather forecasting of atmospheric changes and signs from the planetary astral alterations. Ancient weather forecasting methods relied on observed patterns of events termed pattern recognition. For example, it might be observed that if the sunset was red, the following day brought fair weather.
This experience accumulated over the generations to produce weather lore. However, not all of these predictions prove reliable, many of them have since been found not to stand up to rigorous statistical testing, it was not until the invention of the electric telegraph in 1835 that the modern age of weather forecasting began. Before that, the fastest that distant weather reports could travel was around 100 miles per day, but was more 40–75 miles per day. By the late 1840s, the telegraph allowed reports of weather conditions from a wide area to be received instantaneously, allowing forecasts to be made from knowledge of weather conditions further upwind; the two men credited with the birth of forecasting as a science were an officer of the Royal Navy Francis Beaufort and his protégé Robert FitzRoy. Both were influential men in British naval and governmental circles, though ridiculed in the press at the time, their work gained scientific credence, was accepted by the Royal Navy, formed the basis for all of today's weather forecasting knowledge.
Beaufort developed the Wind Force Scale and Weather Notation coding, which he was to use in his journals for the remainder of his life. He promoted the development of reliable tide tables around British shores, with his friend William Whewell, expanded weather record-keeping at 200 British Coast guard stations. Robert FitzRoy was appointed in 1854 as chief of a new department within the Board of Trade to deal with the collection of weather data at sea as a service to mariners; this was the forerunner of the modern Meteorological Office. All ship captains were tasked with collating data on the weather and computing it, with the use of tested instruments that were loaned for this purpose. A storm in 1859 that caused the loss of the Royal Charter inspired FitzRoy to develop charts to allow predictions to be made, which he called "forecasting the weather", thus coining the term "weather forecast". Fifteen land stations were established to use the telegraph to transmit to him daily reports of weather at set times leading to the first gale warning service.
His warning service for shipping was initiated in February 1861, with the use of telegraph communications. The first daily weather forecasts were published in The Times in 1861. In the following year a system was introduced of hoistin
An aircraft is a machine, able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines. Common examples of aircraft include airplanes, airships and hot air balloons; the human activity that surrounds aircraft is called aviation. The science of aviation, including designing and building aircraft, is called aeronautics. Crewed aircraft are flown by an onboard pilot, but unmanned aerial vehicles may be remotely controlled or self-controlled by onboard computers. Aircraft may be classified by different criteria, such as lift type, aircraft propulsion and others. Flying model craft and stories of manned flight go back many centuries, however the first manned ascent – and safe descent – in modern times took place by larger hot-air balloons developed in the 18th century; each of the two World Wars led to great technical advances. The history of aircraft can be divided into five eras: Pioneers of flight, from the earliest experiments to 1914.
First World War, 1914 to 1918. Aviation between the World Wars, 1918 to 1939. Second World War, 1939 to 1945. Postwar era called the jet age, 1945 to the present day. Aerostats use buoyancy to float in the air in much the same way, they are characterized by one or more large gasbags or canopies, filled with a low-density gas such as helium, hydrogen, or hot air, less dense than the surrounding air. When the weight of this is added to the weight of the aircraft structure, it adds up to the same weight as the air that the craft displaces. Small hot-air balloons called sky lanterns were first invented in ancient China prior to the 3rd century BC and used in cultural celebrations, were only the second type of aircraft to fly, the first being kites which were first invented in ancient China over two thousand years ago. A balloon was any aerostat, while the term airship was used for large, powered aircraft designs – fixed-wing. In 1919 Frederick Handley Page was reported as referring to "ships of the air," with smaller passenger types as "Air yachts."
In the 1930s, large intercontinental flying boats were sometimes referred to as "ships of the air" or "flying-ships". – though none had yet been built. The advent of powered balloons, called dirigible balloons, of rigid hulls allowing a great increase in size, began to change the way these words were used. Huge powered aerostats, characterized by a rigid outer framework and separate aerodynamic skin surrounding the gas bags, were produced, the Zeppelins being the largest and most famous. There were still no fixed-wing aircraft or non-rigid balloons large enough to be called airships, so "airship" came to be synonymous with these aircraft. Several accidents, such as the Hindenburg disaster in 1937, led to the demise of these airships. Nowadays a "balloon" is an unpowered aerostat and an "airship" is a powered one. A powered, steerable aerostat is called a dirigible. Sometimes this term is applied only to non-rigid balloons, sometimes dirigible balloon is regarded as the definition of an airship.
Non-rigid dirigibles are characterized by a moderately aerodynamic gasbag with stabilizing fins at the back. These soon became known as blimps. During the Second World War, this shape was adopted for tethered balloons; the nickname blimp was adopted along with the shape. In modern times, any small dirigible or airship is called a blimp, though a blimp may be unpowered as well as powered. Heavier-than-air aircraft, such as airplanes, must find some way to push air or gas downwards, so that a reaction occurs to push the aircraft upwards; this dynamic movement through the air is the origin of the term aerodyne. There are two ways to produce dynamic upthrust: aerodynamic lift, powered lift in the form of engine thrust. Aerodynamic lift involving wings is the most common, with fixed-wing aircraft being kept in the air by the forward movement of wings, rotorcraft by spinning wing-shaped rotors sometimes called rotary wings. A wing is a flat, horizontal surface shaped in cross-section as an aerofoil. To fly, air must generate lift.
A flexible wing is a wing made of fabric or thin sheet material stretched over a rigid frame. A kite is tethered to the ground and relies on the speed of the wind over its wings, which may be flexible or rigid, fixed, or rotary. With powered lift, the aircraft directs its engine thrust vertically downward. V/STOL aircraft, such as the Harrier Jump Jet and F-35B take off and land vertically using powered lift and transfer to aerodynamic lift in steady flight. A pure rocket is not regarded as an aerodyne, because it does not depend on the air for its lift. Rocket-powered missiles that obtain aerodynamic lift at high speed due to airflow over their bodies are a marginal case; the forerunner of the fixed-wing aircraft is the kite. Whereas a fixed-wing aircraft relies on its forward speed to create airflow over the wings, a kite is tethered to the ground and relies on the wind blowing over its wings to provide lift. Kites were the first kind of aircraft to fly, were invented in China around 500 BC.
Much aerodynamic research was done with kites before test aircraft, wind tunnels, computer modelling programs became available. The first heavier-than-air craft capable of controlled free-flight were gliders. A glider designed by Geo
Weather radar called weather surveillance radar and Doppler weather radar, is a type of radar used to locate precipitation, calculate its motion, estimate its type. Modern weather radars are pulse-Doppler radars, capable of detecting the motion of rain droplets in addition to the intensity of the precipitation. Both types of data can be analyzed to determine the structure of storms and their potential to cause severe weather. During World War II, radar operators discovered that weather was causing echoes on their screen, masking potential enemy targets. Techniques were developed to filter them. Soon after the war, surplus radars were used to detect precipitation. Since weather radar has evolved on its own and is now used by national weather services, research departments in universities, in television stations' weather departments. Raw images are used and specialized software can take radar data to make short term forecasts of future positions and intensities of rain, snow and other weather phenomena.
Radar output is incorporated into numerical weather prediction models to improve analyses and forecasts. During World War II, military radar operators noticed noise in returned echoes due to rain and sleet. After the war, military scientists returned to civilian life or continued in the Armed Forces and pursued their work in developing a use for those echoes. In the United States, David Atlas at first working for the Air Force and for MIT, developed the first operational weather radars. In Canada, J. S. Marshall and R. H. Douglas formed the "Stormy Weather Group" in Montreal. Marshall and his doctoral student Walter Palmer are well known for their work on the drop size distribution in mid-latitude rain that led to understanding of the Z-R relation, which correlates a given radar reflectivity with the rate at which rainwater is falling. In the United Kingdom, research continued to study the radar echo patterns and weather elements such as stratiform rain and convective clouds, experiments were done to evaluate the potential of different wavelengths from 1 to 10 centimeters.
By 1950 the UK company EKCO was demonstrating its airborne'cloud and collision warning search radar equipment'. In 1953 Donald Staggs, an electrical engineer working for the Illinois State Water Survey, made the first recorded radar observation of a "hook echo" associated with a tornadic thunderstorm. Between 1950 and 1980, reflectivity radars, which measure position and intensity of precipitation, were incorporated by weather services around the world; the early meteorologists had to watch a cathode ray tube. During the 1970s, radars began to be organized into networks; the first devices to capture radar images were developed. The number of scanned angles was increased to get a three-dimensional view of the precipitation, so that horizontal cross-sections and vertical cross-sections could be performed. Studies of the organization of thunderstorms were possible for the Alberta Hail Project in Canada and National Severe Storms Laboratory in the US in particular; the NSSL, created in 1964, began experimentation on dual polarization signals and on Doppler effect uses.
In May 1973, a tornado devastated Union City, just west of Oklahoma City. For the first time, a Dopplerized 10 cm wavelength radar from NSSL documented the entire life cycle of the tornado; the researchers discovered a mesoscale rotation in the cloud aloft before the tornado touched the ground – the tornadic vortex signature. NSSL's research helped convince the National Weather Service that Doppler radar was a crucial forecasting tool; the Super Outbreak of tornadoes on 3–4 April 1974 and their devastating destruction might have helped to get funding for further developments. Between 1980 and 2000, weather radar networks became the norm in North America, Europe and other developed countries. Conventional radars were replaced by Doppler radars, which in addition to position and intensity could track the relative velocity of the particles in the air. In the United States, the construction of a network consisting of 10 cm radars, called NEXRAD or WSR-88D, was started in 1988 following NSSL's research.
In Canada, Environment Canada constructed the King City station, with a 5 cm research Doppler radar, by 1985. This led to a complete Canadian Doppler network between 1998 and 2004. France and other European countries had switched to Doppler networks by the early 2000s. Meanwhile, rapid advances in computer technology led to algorithms to detect signs of severe weather, many applications for media outlets and researchers. After 2000, research on dual polarization technology moved into operational use, increasing the amount of information available on precipitation type. "Dual polarization" means that microwave radiation, polarized both horizontally and vertically is emitted. Wide-scale deployment was done by the end of the decade or the beginning of the next in some countries such as the United States and Canada. In April 2013, all United States National Weather Service NEXRADs were dual-polarized. Since 2003, the U. S. National Oceanic and Atmospheric Administration has been experimenting with phased-array radar as a replacement for conventional parabolic antenna to provide more time resolution in atmospheric sounding.
This could be significant with severe thunderstorms, as their evolution can be better evaluated with more timely data. In 2003, the National Science Foundation established the Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere
Aviation, or air transport, refers to the activities surrounding mechanical flight and the aircraft industry. Aircraft includes fixed-wing and rotary-wing types, morphable wings, wing-less lifting bodies, as well as lighter-than-air craft such as balloons and airships. Aviation began in the 18th century with the development of the hot air balloon, an apparatus capable of atmospheric displacement through buoyancy; some of the most significant advancements in aviation technology came with the controlled gliding flying of Otto Lilienthal in 1896. Since that time, aviation has been technologically revolutionized by the introduction of the jet which permitted a major form of transport throughout the world; the word aviation was coined by the French writer and former naval officer Gabriel La Landelle in 1863. He derived the term from the verb avier, itself derived from the Latin word avis and the suffix -ation. There are early legends of human flight such as the stories of Icarus in Greek myth and Jamshid and Shah Kay Kāvus in Persian myth.
Somewhat more credible claims of short-distance human flights appear, such as the flying automaton of Archytas of Tarentum, the winged flights of Abbas ibn Firnas, Eilmer of Malmesbury, the hot-air Passarola of Bartholomeu Lourenço de Gusmão. The modern age of aviation began with the first untethered human lighter-than-air flight on November 21, 1783, of a hot air balloon designed by the Montgolfier brothers; the practicality of balloons was limited. It was recognized that a steerable, or dirigible, balloon was required. Jean-Pierre Blanchard flew the first human-powered dirigible in 1784 and crossed the English Channel in one in 1785. Rigid airships became the first aircraft to transport passengers and cargo over great distances; the best known aircraft of this type were manufactured by the German Zeppelin company. The most successful Zeppelin was the Graf Zeppelin, it flew over one million miles, including an around-the-world flight in August 1929. However, the dominance of the Zeppelins over the airplanes of that period, which had a range of only a few hundred miles, was diminishing as airplane design advanced.
The "Golden Age" of the airships ended on May 6, 1937 when the Hindenburg caught fire, killing 36 people. The cause of the Hindenburg accident was blamed on the use of hydrogen instead of helium as the lift gas. An internal investigation by the manufacturer revealed that the coating used in the material covering the frame was flammable and allowed static electricity to build up in the airship. Changes to the coating formulation reduced the risk of further Hindenburg type accidents. Although there have been periodic initiatives to revive their use, airships have seen only niche application since that time. In 1799, Sir George Cayley set forth the concept of the modern airplane as a fixed-wing flying machine with separate systems for lift and control. Early dirigible developments included machine-powered propulsion, rigid frames and improved speed and maneuverability There are many competing claims for the earliest powered, heavier-than-air flight; the first recorded powered flight was carried out by Clément Ader on October 9, 1890 in his bat-winged self-propelled fixed-wing aircraft, the Ader Éole.
It was the first manned, heavier-than-air flight of a significant distance but insignificant altitude from level ground. Seven years on 14 October 1897, Ader's Avion III was tested without success in front of two officials from the French War ministry; the report on the trials was not publicized until 1910. In November 1906 Ader claimed to have made a successful flight on 14 October 1897, achieving an "uninterrupted flight" of around 300 metres. Although believed at the time, these claims were discredited; the Wright brothers made the first successful powered and sustained airplane flight on December 17, 1903, a feat made possible by their invention of three-axis control. Only a decade at the start of World War I, heavier-than-air powered aircraft had become practical for reconnaissance, artillery spotting, attacks against ground positions. Aircraft began to transport people and cargo as designs grew more reliable; the Wright brothers took aloft the first passenger, Charles Furnas, one of their mechanics, on May 14, 1908.
During the 1920s and 1930s great progress was made in the field of aviation, including the first transatlantic flight of Alcock and Brown in 1919, Charles Lindbergh's solo transatlantic flight in 1927, Charles Kingsford Smith's transpacific flight the following year. One of the most successful designs of this period was the Douglas DC-3, which became the first airliner to be profitable carrying passengers starting the modern era of passenger airline service. By the beginning of World War II, many towns and cities had built airports, there were numerous qualified pilots available; the war brought many innovations to aviation, including the first jet aircraft and the first liquid-fueled rockets. After World War II in North America, there was a boom in general aviation, both private and commercial, as thousands of pilots were released from military service and many inexpensive war-surplus transport and training aircraft became available. Manufacturers such as Cessna and Beechcraft expanded production to provide light aircraft for the new middle-class market.
Flight plans are documents filed by a pilot or flight dispatcher with the local Civil Aviation Authority prior to departure which indicate the plane's planned route or flight path. Flight plan format is specified in ICAO Doc 4444, they include basic information such as departure and arrival points, estimated time en route, alternate airports in case of bad weather, type of flight, the pilot's information, number of people on board and information about the aircraft itself. In most countries, flight plans are required for flights under IFR, but may be optional for flying VFR unless crossing international borders. Flight plans are recommended when flying over inhospitable areas, such as water, as they provide a way of alerting rescuers if the flight is overdue. In the United States and Canada, when an aircraft is crossing the Air Defense Identification Zone, either an IFR or a special type of VFR flight plan called a DVFR flight plan must be filed. For IFR flights, flight plans are used by air traffic control to initiate tracking and routing services.
For VFR flights, their only purpose is to provide needed information should search and rescue operations be required, or for use by air traffic control when flying in a "Special Flight Rules Area". Routing types used in flight planning are: airway and direct. A route may be composed of segments of different routing types. For example, a route from Chicago to Rome may include airway routing over the U. S. and Europe, but direct routing over the Atlantic Ocean. Airway routing occurs along pre-defined pathways called flight paths. Airways can be thought of as three-dimensional highways for aircraft. In most land areas of the world, aircraft are required to fly airways between the departure and destination airports; the rules governing airway routing cover altitude and requirements for entering and leaving the airway. Most airways are eight nautical miles wide, the airway flight levels keep aircraft separated by at least 1000 vertical feet from aircraft on the flight level above and below. Airways intersect at Navaids, which designate the allowed points for changing from one airway to another.
Airways have names consisting of one or more letters followed by one or more digits. The airway structure is divided into low altitudes; the low altitude airways in the U. S. which can be navigated using VOR Navaids have names that start with the letter V, are therefore called Victor Airways. They cover altitudes from 1200 feet above ground level to 17,999 feet above mean sea level. T routes are low altitude RNAV only routes which may or may not utilize VOR NAVAIDS; the high altitude airways in the U. S. have names that are called Jet Routes, or Q for Q routes. Q routes in the U. S. are RNAV only high altitude airways. J & Q routes run from 18,000 feet to 45,000 feet; the altitude separating the low and high airway structures varies from country to country. For example, it is 19,500 feet in Switzerland, 25,500 feet in Egypt. Navaid routing occurs between Navaids. Navaid routing is only allowed in the continental U. S. If a flight plan specifies Navaid routing between two Navaids which are connected via an airway, the rules for that particular airway must be followed as if the aircraft was flying Airway routing between those two Navaids.
Allowable altitudes are covered in Flight Levels. Direct routing occurs when one or both of the route segment endpoints are at a latitude/longitude, not located at a Navaid; some flight planning organizations specify that checkpoints generated for a Direct route be a limited distance apart, or limited by time to fly between the checkpoints. SIDs and STARs are procedures and checkpoints used to enter and leave the airway system by aircraft operating on IFR flight plans. There is a defined transition point at which a SID or STAR intersect. A SID, or Standard Instrument Departure, defines a pathway out of an airport and onto the airway structure. A SID is sometimes called a Departure Procedure. SIDs are unique to the associated airport. A STAR, or Standard Terminal Arrival Route, defines a pathway into an airport from the airway structure. STARs can be associated with more than one arrival airport, which can occur when two or more airports are in proximity. In general, flight planners are expected to avoid areas called Special Use Airspace when planning a flight.
In the United States, there are several types of SUA, including Restricted, Prohibited and Military Operations Area. Examples of Special Use Airspace include a region around the White House in Washington, D. C. and the country of Cuba. Government and military aircraft may have different requirements for particular SUA areas, or may be able to acquire special clearances to traverse through these areas. Flight levels are used by air traffic controllers to simplify the vertical separation of aircraft and one exists every 1000 feet relative to an agreed pressure level. Above a transitional altitude, which varies from country to country, the worldwide arbitrary pressure datum of 1013.25 millibar or the equivalent setting of 29.92 inches of mercury is entered into the altimeter and altitude is referred to as a flight level. The altimeter read