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
The Airport/Facility Directory, now identified as Chart Supplement in the U. S. is a pilot’s manual that provides comprehensive information on airports and small, other aviation facilities and procedures. The directory is published in seven volumes that cover the continental United States, Puerto Rico, the U. S. Virgin Islands; each volume is updated every 56 days by the United States Department of Transportation with information from the Federal Aviation Administration and the National Aviation Charting Office. Information is provided on public-use and joint-use airports and seaplane bases; the directory includes data that cannot be depicted in graphic form, including airport hours. In addition, each A/FD contains information such as parachute jumping areas and facility telephone numbers; the Airport/Facility Directory provides a means for the FAA to communicate, in text form, updates to visual navigation charts between their revision dates — VFR Sectional and Terminal Area Charts are revised every six months.
Volumes are side-bound at 5⅜ x 8¼ inches, colored a distinctive green. As technology has improved, several vendors have started to offer some or all of the information from these guides in electronic form; the seven volumes the A/FD is published in are: Northeast U. S. Southeast U. S. East Central U. S. North Central U. S. South Central U. S. Northwest U. S. Southwest U. S; the facility descriptions in each book are ordered by state, by city within the state. Separate A/FDs are contained in the Pacific Chart Supplement; this sample page shows the entry for Forrest City Municipal, in Arkansas. The airport's FAA location identifier is FCY, it is 4 nautical miles south of the city, its time zone is UTC-6, the geographical coordinates of its Airport Reference Point are 34°56.52′N 90°46.50′W. It can be found on the Memphis VFR Sectional chart, the low-level en route chart 14F, it has at least one Instrument Approach Procedure, described elsewhere. The airport’s elevation is 249 feet, it has a rotating beacon at night, both 100-octane avgas and jet fuel are available although there is no mechanical servicing facility.
There is one runway, 18–36. There is medium intensity runway lighting. Runway 36 has trees obstructing its approach. Free-text remarks follow. There is no control tower; the associated Flight Service Station is Jonesboro, with the telephone number and "Notices to Airmen" file code noted. Radar-assisted approach and departure control are provided by Memphis Center on 135.3 MHz. Associated navigational installations are the Gilmore low-altitude VOR on 113.0 MHz, with an identifier of GQE, at the location indicated, a non-directional beacon on 332 kHz, identified by FCY, on the airfield. This beacon is not monitored by the FAA for continuous operation during the hours shown. A sketch map provides a visual orientation of the airport’s layout and nearby obstructions trees; this article contains text taken from public-domain from the National Aeronautical Charting Office and FAA-H-8083-25, the Pilot’s Handbook of Aeronautical Knowledge. Canada Flight Supplement – Canada's version of the same document. FAA National Charting Office: A/FD description and order form Digital Airport/Facility Directory Chart Supplement The Digital Pilot – Free PDF downloads of Airport/Facility Directory
Air traffic control
Air traffic control is a service provided by ground-based air traffic controllers who direct aircraft on the ground and through controlled airspace, can provide advisory services to aircraft in non-controlled airspace. The primary purpose of ATC worldwide is to prevent collisions and expedite the flow of air traffic, provide information and other support for pilots. In some countries, ATC is operated by the military. To prevent collisions, ATC enforces traffic separation rules, which ensure each aircraft maintains a minimum amount of empty space around it at all times. Many aircraft have collision avoidance systems, which provide additional safety by warning pilots when other aircraft get too close. In many countries, ATC provides services to all private and commercial aircraft operating within its airspace. Depending on the type of flight and the class of airspace, ATC may issue instructions that pilots are required to obey, or advisories that pilots may, at their discretion, disregard; the pilot in command is the final authority for the safe operation of the aircraft and may, in an emergency, deviate from ATC instructions to the extent required to maintain safe operation of their aircraft.
Pursuant to requirements of the International Civil Aviation Organization, ATC operations are conducted either in the English language or the language used by the station on the ground. In practice, the native language for a region is used. In 1920, Croydon Airport, London was the first airport in the world to introduce air traffic control. In the United States, air traffic control developed three divisions; the first of air mail radio stations was created in 1922 after World War I when the U. S. Post Office began using techniques developed by the Army to direct and track the movements of reconnaissance aircraft. Over time, the AMRS morphed into flight service stations. Today's flight service stations do not issue control instructions, but provide pilots with many other flight related informational services, they do relay control instructions from ATC in areas where flight service is the only facility with radio or phone coverage. The first airport traffic control tower, regulating arrivals and surface movement of aircraft at a specific airport, opened in Cleveland in 1930.
Approach/departure control facilities were created after adoption of radar in the 1950s to monitor and control the busy airspace around larger airports. The first air route traffic control center, which directs the movement of aircraft between departure and destination was opened in Newark, NJ in 1935, followed in 1936 by Chicago and Cleveland; the primary method of controlling the immediate airport environment is visual observation from the airport control tower. The tower is a windowed structure located on the airport grounds. Air traffic controllers are responsible for the separation and efficient movement of aircraft and vehicles operating on the taxiways and runways of the airport itself, aircraft in the air near the airport 5 to 10 nautical miles depending on the airport procedures. Surveillance displays are available to controllers at larger airports to assist with controlling air traffic. Controllers may use a radar system called secondary surveillance radar for airborne traffic approaching and departing.
These displays include a map of the area, the position of various aircraft, data tags that include aircraft identification, speed and other information described in local procedures. In adverse weather conditions the tower controllers may use surface movement radar, surface movement guidance and control systems or advanced SMGCS to control traffic on the manoeuvring area; the areas of responsibility for tower controllers fall into three general operational disciplines: local control or air control, ground control, flight data / clearance delivery—other categories, such as Apron control or ground movement planner, may exist at busy airports. While each tower may have unique airport-specific procedures, such as multiple teams of controllers at major or complex airports with multiple runways, the following provides a general concept of the delegation of responsibilities within the tower environment. Remote and virtual tower is a system based on air traffic controllers being located somewhere other than at the local airport tower and still able to provide air traffic control services.
Displays for the air traffic controllers may be live video, synthetic images based on surveillance sensor data, or both. Ground control is responsible for the airport "movement" areas, as well as areas not released to the airlines or other users; this includes all taxiways, inactive runways, holding areas, some transitional aprons or intersections where aircraft arrive, having vacated the runway or departure gate. Exact areas and control responsibilities are defined in local documents and agreements at each airport. Any aircraft, vehicle, or person walking or working in these areas is required to have clearance from ground control; this is done via VHF/UHF radio, but there may be special cases where other procedures are used. Aircraft or vehicles without radios must respond to ATC instructions via aviation light signals or else be led by vehicles with radios. People working on the airport surface have a communications link through which they can communicate with ground control either by handheld radio or cell phone.
Ground control is vital to the smooth operation of the airport, because this position impacts th
Instrument flight rules
Instrument flight rules is one of two sets of regulations governing all aspects of civil aviation aircraft operations. The U. S. Federal Aviation Administration's Instrument Flying Handbook defines IFR as: "Rules and regulations established by the FAA to govern flight under conditions in which flight by outside visual reference is not safe. IFR flight depends upon flying by reference to instruments in the flight deck, navigation is accomplished by reference to electronic signals." It is a term used by pilots and controllers to indicate the type of flight plan an aircraft is flying, such as an IFR or VFR flight plan. To put instrument flight rules into context, a brief overview of visual flight rules is necessary, it is possible and straightforward, in clear weather conditions, to fly a plane by reference to outside visual cues, such as the horizon to maintain orientation, nearby buildings and terrain features for navigation, other aircraft to maintain separation. This is known as operating the aircraft under VFR, is the most common mode of operation for small aircraft.
However, it is safe to fly VFR only when these outside references can be seen from a sufficient distance. Thus, cloud ceiling and flight visibility are the most important variables for safe operations during all phases of flight; the minimum weather conditions for ceiling and visibility for VFR flights are defined in FAR Part 91.155, vary depending on the type of airspace in which the aircraft is operating, on whether the flight is conducted during daytime or nighttime. However, typical daytime VFR minimums for most airspace is 3 statute miles of flight visibility and a distance from clouds of 500' below, 1,000' above, 2,000' feet horizontally. Flight conditions reported as equal to or greater than these VFR minimums are referred to as visual meteorological conditions. Any aircraft operating under VFR must have the required equipment on board, as described in FAR Part 91.205. VFR pilots may use cockpit instruments as secondary aids to navigation and orientation, but are not required to. Visual flight rules are simpler than instrument flight rules, require less training and practice.
VFR provides a great degree of freedom, allowing pilots to go where they want, when they want, allows them a much wider latitude in determining how they get there. When operation of an aircraft under VFR is not safe, because the visual cues outside the aircraft are obscured by weather, instrument flight rules must be used instead. IFR permits an aircraft to operate in instrument meteorological conditions, any weather condition less than VMC but in which aircraft can still operate safely. Use of instrument flight rules is required when flying in "Class A" airspace regardless of weather conditions. Class A airspace extends from 18,000 feet above mean sea level to flight level 600 above the contiguous 48 United States and overlying the waters within 12 miles thereof. Flight in Class A airspace requires pilots and aircraft to be instrument equipped and rated and to be operating under Instrument Flight Rules. In many countries commercial airliners and their pilots must operate under IFR as the majority of flights enter Class A airspace.
Procedures and training are more complex compared to VFR instruction, as a pilot must demonstrate competency in conducting an entire cross-country flight by reference to instruments. Instrument pilots must meticulously evaluate weather, create a detailed flight plan based around specific instrument departure, en route, arrival procedures, dispatch the flight; the distance by which an aircraft avoids obstacles or other aircraft is termed separation. The most important concept of IFR flying is that separation is maintained regardless of weather conditions. In controlled airspace, air traffic control separates IFR aircraft from obstacles and other aircraft using a flight clearance based on route, distance and altitude. ATC monitors IFR flights on radar, or through aircraft position reports in areas where radar coverage is not available. Aircraft position reports are sent as voice radio transmissions. In the United States, a flight operating under IFR is required to provide position reports unless ATC advises a pilot that the plane is in radar contact.
The pilot must resume position reports after ATC advises that radar contact has been lost, or that radar services are terminated. IFR flights in controlled airspace require an ATC clearance for each part of the flight. A clearance always specifies a clearance limit, the farthest the aircraft can fly without a new clearance. In addition, a clearance provides a heading or route to follow and communication parameters, such as frequencies and transponder codes. In uncontrolled airspace, ATC clearances are unavailable. In some states a form of separation is provided to certain aircraft in uncontrolled airspace as far as is practical, but separation is not mandated nor provided. Despite the protection offered by flight in controlled airspace under IFR, the ultimate responsibility for the safety of the aircraft rests with the pilot in command, who can refuse clearances, it is essential to differentiate between flig
Aviation fuel is a specialized type of petroleum-based fuel used to power aircraft. It is of a higher quality than fuels used in less critical applications, such as heating or road transport, contains additives to reduce the risk of icing or explosion due to high temperature, among other properties. Most current commercial airlines and military aircraft use jet fuel for maximum fuel efficiency and lowest cost; these aircraft account for the vast majority of aviation fuel refined today, used in diesel aircraft engines. Other aviation fuels available for aircraft are kinds of petroleum spirit used in engines with spark plugs. Specific energy is the important criterion in selecting an appropriate fuel to power an aircraft. Much of the weight of an aircraft goes into fuel storage to provide the range, more weight means more fuel consumption. Aircraft have a high peak power and thus fuel demand during landing; this has so far prevented electric aircraft using electric batteries as the main propulsion energy store becoming commercially viable.
Jet fuel is a clear to straw-colored fuel, based on either an unleaded kerosene, or a naphtha-kerosene blend. Similar to diesel fuel, it can be used in either compression ignition engines or turbine engines. Jet-A powers modern commercial airliners and is a mix of pure kerosene and burns at temperatures at or above 49 °C. Kerosene-based fuel has a much higher flash point than gasoline-based fuel, meaning that it requires higher temperature to ignite, it is a high-quality fuel. Avgas is used in spark-ignited internal-combustion engines in aircraft, its formulation is distinct from mogas used in cars and many military vehicles, such as the "Deuce and a Half". Formulated for stability and predictable performance under a wide range of environments, avgas is used in aircraft which use reciprocating or Wankel engines. Alternatives to conventional fossil-based aviation fuels, new fuels made via the biomass to liquid method and certain straight vegetable oils can be used. Fuels such as sustainable aviation fuel have the advantage that few or no modifications are necessary on the aircraft itself, provided that the fuel characteristics meet specifications for lubricity and density as well as adequately swelling elastomer seals in current aircraft fuel systems.
Sustainable aviation fuel and blends of fossil and sustainably-sourced alternative fuels yield lower emissions of particles and GHGs. They are, not being used because they still face political and economic barriers, such as being more expensive than conventionally produced aviation fuels by a wide margin. Compressed natural gas and liquified natural gas are fuel feedstocks that aircraft could switch to, other than conventional fossil-oil. Turbofans for instance can be operated on a number of different fuels, some have been made optimized for use with natural gas; some aircraft, such as the Tupolev Tu-155, as well as the "SUGAR Freeze" aircraft under NASA's N+4 Advanced Concept Development program, were designed to run on LNG. The low specific energy of natural gas in liquid form compared to conventional fuels gives it a distinct disadvantage for flight applications; the production of aviation fuel falls into two categories: fuel suitable for turbine engines and fuel suitable for internal combustion engines.
There are international specifications for each. Jet fuel is used in both turboprop and jet aircraft, must maintain a low viscosity at low temperature, meet definite limits in terms of density and calorific value, burn cleanly, remain chemically stable when heated to high temperature. Aviation gasoline referred to as "avgas" or 100-LL, is a refined form of gasoline for aircraft, with an emphasis on purity, anti-knock characteristics and minimization of spark plug fouling. Avgas must meet performance guidelines for both the rich mixture condition required for take-off power settings and the leaner mixtures used during cruise to reduce fuel consumption. Avgas is to many more individual aircraft operators; the net energy content for aviation fuels depends on their composition. Some typical values are: BP Avgas 80, 44.65 MJ/kg, density at 15 °C is 690 kg/m3. Kerosene type BP Jet A-1, 43.15 MJ/kg, density at 15 °C is 804 kg/m3. Kerosene type BP Jet TS-1, 43.2 MJ/kg, density at 15 °C is 787 kg/m3. In performance calculations, airliner manufacturers use a density of jet fuel around 6.7 lb/USgal or 0.8 kg/l.
Specific cases are: Bombardier Aerospace: The Challenger Multi-role Aircraft is a special mission variant of the Bombardier Challenger 650 business jet platform. Bombardier bases performance on the use of fuel with an average lower heating value of 18,550 BTU/lb and a density of 0.809 kg/l. Embraer: In its airport planning manual for the E195 uses an adopted fuel density of 0.811 kg/l. Aviation fuels consist of blends of over two thousand chemicals hydrocarbons, additives such as antioxidants and metal deactivators, static reducers, icing inhibitors, corrosion inhibitors, impurities. Principal components include isooctane. Like other f
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
An aerodrome or airdrome is a location from which aircraft flight operations take place, regardless of whether they involve air cargo, passengers, or neither. Aerodromes include small general aviation airfields, large commercial airports, military airbases; the term airport may imply a certain stature. This means that all airports are aerodromes. Usage of the term "aerodrome" remains more common in the Ireland and Commonwealth nations. A water aerodrome is an area of open water used by seaplanes or amphibious aircraft for landing and taking off. According to the International Civil Aviation Organization an aerodrome is "A defined area on land or water intended to be used either wholly or in part for the arrival and surface movement of aircraft." The word aerodrome derives from Ancient Greek ἀήρ, δρόμος, road or course meaning air course. An ancient linguistic parallel is hippodrome, derived from ἵππος, δρόμος, course. A modern linguistic parallel is an arena for velocipedes. Αεροδρόμιο is the word for airport in Modern Greek.
In British military usage, the Royal Flying Corps in the First World War and the Royal Air Force in the First and Second World Wars used the term—it had the advantage that their French allies, on whose soil they were based and with whom they co-operated, used the cognate term aérodrome. In Canada and Australia, aerodrome is a legal term of art for any area of land or water used for aircraft operation, regardless of facilities. International Civil Aviation Organization documents use the term aerodrome, for example, in the Annex to the ICAO Convention about aerodromes, their physical characteristics, their operation. However, the terms airfield or airport superseded use of aerodrome after World War II, in colloquial language. In the early days of aviation, when there were no paved runways and all landing fields were grass, a typical airfield might permit takeoffs and landings in only a couple of directions, much like today's airports, whereas an aerodrome was distinguished, by virtue of its much greater size, by its ability to handle landings and take offs in any direction.
The ability to always take off and land directly into the wind, regardless of the wind's direction, was an important advantage in the earliest days of aviation when an airplane's performance in a crosswind takeoff or landing might be poor or dangerous. The development of differential braking in aircraft, improved aircraft performance, utilization of paved runways, the fact that a circular aerodrome required much more space than did the "L" or triangle shaped airfield made the early aerodromes obsolete; the city of the first aerodrome in the world is a French commune named Viry-Chatillon. The unimproved airfield remains a phenomenon in military aspects; the DHC-4 Caribou served in the U. S. military in Vietnam, landing on rough, unimproved airfields where the C-130 workhorse could not operate. Earlier, the Ju 52 and Fieseler Storch could do the same, one example of the latter taking off from the Führerbunker whilst surrounded by Russian troops. An airport is an aerodrome certificated for commercial flights.
An air base is an aerodrome with significant facilities to support crew. The term is reserved for military bases, but applies to civil seaplane bases. An airstrip is a small aerodrome that consists only of a runway with fueling equipment, they are in remote locations. Many airstrips were built on the hundreds of islands in the Pacific Ocean during World War II. A few airstrips grew to become full-fledged airbases as strategic or economic importance of a region increased over time. An Advanced Landing Ground was a temporary airstrip used by the Allies in the run-up to and during the invasion of Normandy, these were built both in Britain, on the continent. A water aerodrome is an area of open water used by seaplanes or amphibious aircraft for landing and taking off, it may have a terminal building on land and/or a place where the plane can come to shore and dock like a boat to load and unload. The Canadian Aeronautical Information Manual says "...for the most part, all of Canada can be an aerodrome", however there are "registered aerodromes" and "certified airports".
To become a registered aerodrome the operator must maintain certain standards and keep the Minister of Transport informed of any changes. To be certified as an airport the aerodrome, which supports commercial operations, must meet safety standards. Nav Canada, the private company responsible for air traffic control services in Canada, publishes the Canada Flight Supplement, a directory of all registered Canadian land aerodromes, as well as the Canada Water Aerodrome Supplement. Casement Aerodrome is the main military airport used by the Irish Air Corps; the term "aerodrome" is used for airports and airfields of lesser importance in Ireland, such as those at Abbeyshrule. Spaceport