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Minimum En Route Altitude
Minimum en route altitude (MEA), alternately spelled as Minimum enroute altitude, is the lowest published altitude between radio navigation fixes that assures acceptable navigational signal coverage (see MRA) ''and'' meets obstacle clearance requirements (see MOCA) between those fixes. The definition given here is that of the United States Federal Aviation Administration. Details may vary in other jurisdictions. Overview The MEA prescribed for a Federal airway or segment, RNAV low or high route, or other direct route applies to the entire width of the airway, segment, or route. MEAs for routes wholly contained within controlled airspace normally provide a buffer above the floor of controlled airspace consisting of at least 300 feet within transition areas and 500 feet within control areas. MEAs are established based upon obstacle clearance over terrain and man-made objects, adequacy of navigation facility performance, and communications requirements, although adequate communi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Navigation
Radio navigation or radionavigation is the application of radio frequencies to determine a position of an object on the Earth, either the vessel or an obstruction. Like radiolocation, it is a type of radiodetermination. The basic principles are measurements from/to electric beacons, especially * Angular directions, e.g. by bearing, radio phases or interferometry, * Distances, e.g. ranging by measurement of time of flight between one transmitter and multiple receivers or vice versa, * Distance ''differences'' by measurement of times of arrival of signals from one transmitter to multiple receivers or vice versa * Partly also velocity, e.g. by means of radio Doppler shift. Combinations of these measurement principles also are important—e.g., many radars measure range and azimuth of a target. Bearing-measurement systems These systems used some form of directional radio antenna to determine the location of a broadcast station on the ground. Conventional navigation techniques a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minimum Reception Altitude
In aviation, minimum reception altitude (MRA) is the lowest altitude on an airway segment where an aircraft can be assured of receiving signals from off-course navigation aids like VOR that define a fix. An MRA is determined by FAA flight inspection traversing an entire route of flight to establish the minimum altitude the navigation signal can be received for the route (which, along with obstacle clearance, defines the Minimum Enroute Altitude - MEA) and for off-course NAVAID facilities that determine a fix. When the MRA at the fix is higher than the MEA, an MRA is established for the fix, and is the lowest altitude at which an intersection can be determined.https://www.faa.gov/regulations_policies/handbooks_manuals/aviation/instrument_procedures_handbook/media/FAA-H-8083-16B_Glossary.pdf See also *Above ground level *Minimum en route altitude Minimum en route altitude (MEA), alternately spelled as Minimum enroute altitude, is the lowest published altitude between radio navigation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minimum Obstacle Clearance Altitude
Minimum Obstacle Clearance Altitude, or ''MOCA'', is the lowest published altitude in effect between fixes on VOR airways or route segments that meets obstacle (like a building or a tower) clearance requirements for the entire route segment. Within the United States, this altitude also assures acceptable navigational signal coverage only within 22 nm of a VOR. The MOCA seen on the NACO en route chart, may have been computed by adding the required obstacle clearance (ROC) to the controlling obstacle in the primary area or computed by using a TERPS chart if the controlling obstacle is located in the secondary area. This figure is then rounded to the nearest 100 foot increment, i.e. 2,049 feet becomes 2,000, and 2,050 feet becomes 2,100 feet. An extra 2,000 feet is added in mountainous areas, 1,000 in non-mountainous. The MOCA is based upon obstacle clearance over the terrain or over manmade objects, adequacy of navigation facility performance, and communications requirements. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territories, nine Minor Outlying Islands, and 326 Indian reservations. The United States is also in free association with three Pacific Island sovereign states: the Federated States of Micronesia, the Marshall Islands, and the Republic of Palau. It is the world's third-largest country by both land and total area. It shares land borders with Canada to its north and with Mexico to its south and has maritime borders with the Bahamas, Cuba, Russia, and other nations. With a population of over 333 million, it is the most populous country in the Americas and the third most populous in the world. The national capital of the United States is Washington, D.C. and its most populous city and principal financial center is New York City. Paleo-Americ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Federal Aviation Administration
The Federal Aviation Administration (FAA) is the largest transportation agency of the U.S. government and regulates all aspects of civil aviation in the country as well as over surrounding international waters. Its powers include air traffic management, certification of personnel and aircraft, setting standards for airports, and protection of U.S. assets during the launch or re-entry of commercial space vehicles. Powers over neighboring international waters were delegated to the FAA by authority of the International Civil Aviation Organization. Created in , the FAA replaced the former Civil Aeronautics Administration (CAA) and later became an agency within the U.S. Department of Transportation. Major functions The FAA's roles include: *Regulating U.S. commercial space transportation *Regulating air navigation facilities' geometric and flight inspection standards *Encouraging and developing civil aeronautics, including new aviation technology *Issuing, suspending, or revoking ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Airway (aviation)
In the United States, airways or air routes are defined by the Federal Aviation Administration (FAA) in two ways: "VOR Federal airways and Low/Medium Frequency (L/MF) (Colored) Federal airways" These are designated routes which aeroplanes fly to aid in navigation and help with separation to avoid accidents. Airways are defined with segments within a specific altitude block, corridor width, and between fixed geographic coordinates for satellites navigation system, or between ground-based radio transmitter navigational aids (navaids; such as VORs or NDBs) or the intersection of specific radials of two navaids. United States To guide airmail pilots on their delivery routes, the United States Postal Service constructed the first airways in the United States, the Contract Air Mail routes. These airways were between major cities and identified at night by a series of flashing lights and beacons which pilots flew over in sequence to get from one city to the next. Intermediate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RNAV
Area navigation (RNAV, usually pronounced as "''ar-nav"'') is a method of instrument flight rules (IFR) navigation that allows an aircraft to choose any course within a network of navigation beacons, rather than navigate directly to and from the beacons. This can conserve flight distance, reduce congestion, and allow flights into airports without beacons. Area navigation used to be called "random navigation", hence the acronym RNAV. RNAV can be defined as a method of navigation that permits aircraft operation on any desired course within the coverage of station-referenced navigation signals or within the limits of a self-contained system capability, or a combination of these. In the United States, RNAV was developed in the 1960s, and the first such routes were published in the 1970s. In January 1983, the Federal Aviation Administration revoked all RNAV routes in the contiguous United States due to findings that aircraft were using inertial navigation systems rather than the gr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Controlled Airspace
Controlled airspace is airspace of defined dimensions within which air traffic control (ATC) services are provided. The level of control varies with different classes of airspace. Controlled airspace usually imposes higher weather minimums than are applicable in uncontrolled airspace. It is the opposite of uncontrolled airspace. Controlled airspace is established mainly for three different reasons: * high-volume air traffic areas, e.g. near airports * Instrument flight rules traffic under ATC guidance * security, e.g. within an Air Defense Identification Zone Controlled airspace usually exists in the immediate vicinity of busier airports, where aircraft used in commercial air transport flights are climbing out from or making an approach to the airport, or at higher levels where air transport flights would tend to cruise. Some countries also provide controlled airspace almost generally, however in most countries it is common to provide uncontrolled airspace in areas where si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Control Area (aviation)
In aviation, a control area (CTA) is the volume of controlled airspace that exists in the vicinity of an airport. It has a specified lower level and a specified upper level. It usually is situated on top of a control zone and provides protection to aircraft climbing out from the airport by joining the low-level control zone to the nearest airways. In the UK they are generally class A, D or E. Control areas are particularly useful where there are busy airports located close together. In this case a single CTA will sit over all of the individual airports' CTRs. In larger-scale cases, this is known as a terminal manoeuvring area (TMA). See also *Airway (aviation) *Flight information region In aviation, a flight information region (FIR) is a specified region of airspace in which a flight information service and an alerting service (ALRS) are provided. The International Civil Aviation Organization (ICAO) delegates which country is re ... Air traffic control {{Commercial ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Above Ground Level
In aviation, atmospheric sciences and broadcasting, a height above ground level (AGL or HAGL) is a height measured with respect to the underlying ground surface. This is as opposed to height above mean sea level (AMSL or HAMSL), height above ellipsoid (HAE, as reported by a GPS receiver), or height above average terrain (AAT or HAAT, in broadcast engineering). In other words, these expressions (AGL, AMSL, HAE, AAT) indicate where the "zero level" or "reference altitude" - the vertical datum - is located. Aviation A pilot flying an aircraft under instrument flight rules (typically under poor visibility conditions) must rely on the aircraft's altimeter to decide when to deploy the undercarriage and prepare for landing. Therefore, the pilot needs reliable information on the height of the plane with respect to the landing area (usually an airport). The altimeter, which is usually a barometer calibrated in units of distance instead of atmospheric pressure, can therefore be set in su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minimum Safe Altitude
In aviation (particularly in air navigation), lowest safe altitude (LSALT) is an altitude that is at least 500 feet above any obstacle or terrain within a defined safety buffer region around a particular route that a pilot might fly. The safety buffer allows for errors in the air by including an additional area that a pilot might stray into by flying off track. By flying at or above this altitude a pilot complies with terrain clearance requirements on that particular flight leg. Australian definition * The minimum LSALT is 1500 feet. * LSALT is 1360 feet above the highest terrain where any obstacle thereon is less than 360 feet above the terrain, or there is no charted obstacle. * LSALT is 1000 feet above the highest obstacle which is greater than 360 feet above the terrain. For example, if there is an obstacle at 200 feet above terrain of 2500 feet, LSALT is 2500 feet (terrain height) + 1360 feet (clearance height), for an LSALT of 3860 feet; if there is an obstacle at 450 fe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Altitudes In Aviation
Altitude or height (also sometimes known as depth) is a distance measurement, usually in the vertical or "up" direction, between a reference datum and a point or object. The exact definition and reference datum varies according to the context (e.g., aviation, geometry, geographical survey, sport, or atmospheric pressure). Although the term ''altitude'' is commonly used to mean the height above sea level of a location, in geography the term elevation is often preferred for this usage. Vertical distance measurements in the "down" direction are commonly referred to as depth. In aviation In aviation, the term altitude can have several meanings, and is always qualified by explicitly adding a modifier (e.g. "true altitude"), or implicitly through the context of the communication. Parties exchanging altitude information must be clear which definition is being used. Aviation altitude is measured using either mean sea level (MSL) or local ground level (above ground level, or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
