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Holding (aviation)
In aviation, holding (or flying a hold) is a maneuver designed to delay an aircraft already in flight while keeping it within a specified airspace. Implementation A holding pattern for instrument flight rules (IFR) aircraft is usually a racetrack pattern based on a ''holding fix''. This ''fix'' can be a radio beacon such as a non-directional beacon (NDB) or VHF omnidirectional range (VOR). The fix is the start of the first turn of the racetrack pattern. Aircraft will fly towards the fix, and once there will enter a predefined racetrack pattern. A standard holding pattern uses right-hand turns and takes approximately 4 minutes to complete (one minute for each 180-degree turn, and two one-minute straight ahead sections). Deviations from this pattern can happen if long delays are expected; longer legs (usually two or three minutes) may be used, or aircraft with distance measuring equipment (DME) may be assigned patterns with legs defined in nautical miles rather than minutes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mean Sea Level
There are several kinds of mean in mathematics, especially in statistics. Each mean serves to summarize a given group of data, often to better understand the overall value (magnitude and sign) of a given data set. For a data set, the '' arithmetic mean'', also known as "arithmetic average", is a measure of central tendency of a finite set of numbers: specifically, the sum of the values divided by the number of values. The arithmetic mean of a set of numbers ''x''1, ''x''2, ..., x''n'' is typically denoted using an overhead bar, \bar. If the data set were based on a series of observations obtained by sampling from a statistical population, the arithmetic mean is the ''sample mean'' (\bar) to distinguish it from the mean, or expected value, of the underlying distribution, the ''population mean'' (denoted \mu or \mu_x).Underhill, L.G.; Bradfield d. (1998) ''Introstat'', Juta and Company Ltd.p. 181/ref> Outside probability and statistics, a wide range of other notions of mean ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Loiter (aeronautics)
In aeronautics and aviation, loiter is the phase of flight consisting of flying over some small region. In general aviation, the loiter phase generally occurs at the end of the flight, when the plane is waiting for clearance to land. In military flights, such as aerial reconnaissance or ground-attack aircraft, the loiter phase is the time that the aircraft has over a target. Cruise is the time period the aircraft travels to the target and returns after the loiter. In astronautics, the loiter phase of spacecraft used for human spaceflight may be as long as six months, as is the case for Soyuz spacecraft which remain docked while expedition crewmembers reside aboard the International Space Station. Endurance The endurance of the aircraft during the loiter phase is often calculated using the Breguet formula: : E = \frac \frac \ln \left( \frac \right) where: * E \,\! is the endurance (dimensions of Time) * C \,\! is the Specific Fuel Consumption (dimensions of 1/Time) * L \, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flight Planning
Flight planning is the process of producing a flight plan to describe a proposed aircraft flight. It involves two safety-critical aspects: fuel calculation, to ensure that the aircraft can safely reach the destination, and compliance with air traffic control requirements, to minimise the risk of midair collision. In addition, flight planners normally wish to minimise flight cost through the appropriate choice of route, height, and speed, and by loading the minimum necessary fuel on board. Air Traffic Services (ATS) use the completed flight plan for separation of aircraft in air traffic management services, including tracking and finding lost aircraft, during search and rescue (SAR) missions. Flight planning requires accurate weather forecasts so that fuel consumption calculations can account for the fuel consumption effects of head or tail winds and air temperature. Safety regulations require aircraft to carry fuel beyond the minimum needed to fly from origin to destination, all ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heathrow Arrival Stacks
Inbound aircraft to London Heathrow Airport typically follow one of a number of Standard Arrival Routes (STARs). The STARs each terminate at one of four different RNAV waypoints (co-located with VOR navigational aids), and these also define four "stacks" where aircraft can be held, if necessary, until they are cleared to begin their approach to land. Stacks are sections of airspace where inbound aircraft will normally use the pattern closest to their arrival route. They can be visualised as invisible helter skelters in the sky. Each stack descends in 1000 ft (300 m) intervals from 16,000 ft (4,000m) down to 8000 ft (2,100m). If these holds become full, aircraft are held at more distant points before being cleared onward to one of the four main holds. The stacks Bovingdon The Bovingdon stack (BNN) is for arrivals from the north west. It extends above the village of Bovingdon and the town of Chesham, and uses the RNAV waypoint BNN (co-located with the BNN VOR), ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mach Number
Mach number (M or Ma) (; ) is a dimensionless quantity in fluid dynamics representing the ratio of flow velocity past a boundary to the local speed of sound. It is named after the Moravian physicist and philosopher Ernst Mach. : \mathrm = \frac, where: : is the local Mach number, : is the local flow velocity with respect to the boundaries (either internal, such as an object immersed in the flow, or external, like a channel), and : is the speed of sound in the medium, which in air varies with the square root of the thermodynamic temperature. By definition, at Mach1, the local flow velocity is equal to the speed of sound. At Mach0.65, is 65% of the speed of sound (subsonic), and, at Mach1.35, is 35% faster than the speed of sound (supersonic). Pilots of high-altitude aerospace vehicles use flight Mach number to express a vehicle's true airspeed, but the flow field around a vehicle varies in three dimensions, with corresponding variations in local Mach number. The loc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Indicated Airspeed
Indicated airspeed (IAS) is the airspeed of an aircraft as measured by its pitot-static system and displayed by the airspeed indicator (ASI). This is the pilots' primary airspeed reference. This value is not corrected for installation error, instrument error, or the actual encountered air density, being instead calibrated to always reflect the adiabatic compressible flow of the International Standard Atmosphere at sea level. It uses the difference between total pressure and static pressure, provided by the system, to either mechanically or electronically measure dynamic pressure. The dynamic pressure includes terms for both density and airspeed. Since the airspeed indicator cannot know the density, it is by design calibrated to assume the sea level standard atmospheric density when calculating airspeed. Since the actual density will vary considerably from this assumed value as the aircraft changes altitude, IAS varies considerably from true airspeed (TAS), the relative vel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Military Aviation
Military aviation comprises military aircraft and other flying machines for the purposes of conducting or enabling aerial warfare, including national airlift ( air cargo) capacity to provide logistical supply to forces stationed in a war theater or along a front. Airpower includes the national means of conducting such warfare, including the intersection of transport and warcraft. Military aircraft include bombers, fighters, transports, trainer aircraft, and reconnaissance aircraft. History The first military uses of aviation involved lighter-than-air balloons. During the Battle of Fleurus in 1794, the French observation balloon ''l'Entreprenant'' was used to monitor Austrian troop movements. The use of lighter-than-air aircraft in warfare became prevalent in the 19th century, including regular use in the American Civil War. Lighter-than-air military aviation persisted until shortly after World War II, gradually being withdrawn from various roles as heavier-than-air ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Civil Aviation
Civil aviation is one of two major categories of flying, representing all non-military and non-state aviation, both private and commercial. Most of the countries in the world are members of the International Civil Aviation Organization and work together to establish common Standards and Recommended Practices for civil aviation through that agency. Civil aviation includes three major categories: * Commercial air transport, including scheduled and non-scheduled passenger and cargo flights * Aerial work, in which an aircraft is used for specialized services such as agriculture, photography, surveying, search and rescue, etc. * General aviation (GA), including all other civil flights, private or commercial Although scheduled air transport is the larger operation in terms of passenger numbers, GA is larger in the number of flights (and flight hours, in the U.S.) In the U.S., GA carries 166 million passengers each year, more than any individual airline, though less than all the airl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aviation
Aviation includes 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 hot air 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; then a large step in significance came with the construction of the first powered airplane by the Wright brothers in the early 1900s. Since that time, aviation has been technologically revolutionized by the introduction of the jet which permitted a major form of transport throughout the world. Etymology The word ''aviation'' was coined by the French writer and former naval officer Gabriel La Landelle in 1863. He derived the term from th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Code Of Federal Regulations
In the law of the United States, the ''Code of Federal Regulations'' (''CFR'') is the codification of the general and permanent regulations promulgated by the executive departments and agencies of the federal government of the United States. The CFR is divided into 50 titles that represent broad areas subject to federal regulation. The CFR annual edition is published as a special issue of the '' Federal Register'' by the Office of the Federal Register (part of the National Archives and Records Administration) and the Government Publishing Office. In addition to this annual edition, the CFR is published online on the Electronic CFR (eCFR) website, which is updated daily. Background Congress frequently delegates authority to an executive branch agency to issue regulations to govern some sphere. These statutes are called "enabling legislation." Enabling legislation typically has two parts: a substantive scope (typically using language such as "The Secretary shall promulgate r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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