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Altimeter Setting
Altimeter setting is the value of the atmospheric pressure used to adjust the sub-scale of a pressure altimeter so that it indicates the height of an aircraft above a known reference surface. This reference can be the mean sea level pressure (QNH); the pressure at the nearby surface airport (QFE); or the pressure level of {{convert, 1013.25, hPa, inHg, abbr=off, sigfig=4 which gives pressure altitude and is used to maintain one of the standard flight levels. The setting of a sensitive pressure altimeter is shown in the Kollsman window. The altimeter setting QNH is one of the data included in METAR messages from weather stations in addition to the surface pressure. An alternative setting is QFE: #QNH is the barometric altimeter setting that causes an altimeter to read airfield elevation above mean sea level when on the airfield. In ISA temperature conditions the altimeter will read altitude above mean sea level in the vicinity of the airfield. #QFE is the barometric altimeter setti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pressure Altimeter
An altimeter or an altitude meter is an instrument used to measure the altitude of an object above a fixed level. The measurement of altitude is called altimetry, which is related to the term bathymetry, the measurement of depth under water. The most common unit for altimeter calibration worldwide is hectopascals (hPa), except for North America (other than Canada ) and Japan where inches of mercury (inHg) are used. To obtain an accurate altitude reading in either feet or meters, the local barometric pressure must be calibrated correctly using the barometric formula. History The scientific principles behind the altimeter were first written by Rev. Alexander Bryce a Scottish minister and astronomer in 1772 who realised that the principles of a barometer could be adjusted to measure height. Pressure altimeter Altitude can be determined based on the measurement of atmospheric pressure. The greater the altitude, the lower the pressure. When a barometer is supplied with a nonlinear ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
World Meteorological Organization
The World Meteorological Organization (WMO) is a specialized agency of the United Nations responsible for promoting international cooperation on atmospheric science, climatology, hydrology and geophysics. The WMO originated from the International Meteorological Organization, a nongovernmental organization founded in 1873 as a forum for exchanging weather data and research. Proposals to reform the status and structure of the IMO culminated in the World Meteorological Convention of 1947, which formally established the World Meteorological Organization. The Convention entered into force on 23 March 1950, and the following year the WMO began operations as an intergovernmental organization within the UN system. The WMO is made up of 193 countries and territories, and facilitates the "free and unrestricted" exchange of data, information, and research between the respective meteorological and hydrological institutions of its members. It also collaborates with nongovernmental part ... [...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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pressure Altitude
Pressure altitude is the altitude in the International Standard Atmosphere (ISA) with the same atmospheric pressure as that of the part of the atmosphere in question. The National Oceanic and Atmospheric Administration (NOAA) published the following formula for directly converting atmospheric pressure in millibars ( \mathrm ) to pressure altitude in feet ( \mathrm ): : h = 145366.45 \left 1 - \left( \frac \right)^ \right In aviation, pressure altitude is the height above a standard datum plane (SDP), which is a theoretical level where the weight of the atmosphere is as measured by a barometer.Pilot’s Handbook of Aeronautical Knowledge (FAA-H-8083-25B), 2016, Chapter 4, p 4-4 It indicates altitude obtained when an altimeter is set to an agreed baseline pressure under certain circumstances in which the aircraft’s altimeter would be unable to give a useful altitude readout. Examples would be landing at a high altitude or near sea level under conditions of exceptionally high air ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flight Level
In aviation and aviation meteorology, a flight level (FL) is an aircraft's altitude at standard air pressure, expressed in hundreds of feet. The air pressure is computed assuming an International Standard Atmosphere pressure of 1013.25 hPa (29.92 inHg) at sea level, and therefore is not necessarily the same as the aircraft's actual altitude, either above sea level or above ground level. Background Flight levels are used to ensure safe vertical separation between aircraft, despite natural local variations in atmospheric air pressure. Historically, altitude has been measured using a pressure altimeter, which is essentially a calibrated barometer. An altimeter measures ambient air pressure, which decreases with increasing altitude following the barometric formula. It then calculates and displays the corresponding altitude. If different aircraft's altimeters were not calibrated consistently, then two aircraft could be flying at the same altitude even though their alti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paul Kollsman
Paul Kollsman (February 22, 1900 in Germany – September 26, 1982 in Beverly Hills, California) was a German-American inventor. He invented the first sensitive barometer, a key enabler of Instrument flight rules, instrument flight in airplanes. The United States Patent Office cites him as the inventor on 124 patents. Biography Kollsman studied engineering and science in Stuttgart and Munich. In 1923 he emigrated from Germany to the United States, following his younger brother Ernest Otto Kollsman, who had emigrated earlier. He worked as a truck driver or truck driver's assistant until he found a position at Pioneer Instrument Company, Pioneer Instruments Co. in Brooklyn, New York, where he learned to make various aircraft instruments. He left Pioneer in 1928 and with $500 saved while working, Paul and his brother Otto founded Kollsman Instruments Co. in Brooklyn NY. In 1929 US Army Lt. James H. Doolittle was leading the development of equipment and methods for instrumen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
METAR
METAR is a format for reporting weather information. A METAR weather report is predominantly used by aircraft pilots, and by meteorologists, who use aggregated METAR information to assist in weather forecasting. Raw METAR is the most common format in the world for the transmission of observational weather data. It is highly standardized through the International Civil Aviation Organization (ICAO), which allows it to be understood throughout most of the world. Report names The United States Federal Aviation Administration (FAA) in its publication the Aeronautical Information Manual describes the report as ''aviation routine weather report'' while the international authority for the code form, the World Meteorological Organization (WMO), describes it as the ''aerodrome routine meteorological report.'' The National Oceanic and Atmospheric Administration (part of the United States Department of Commerce) and the United Kingdom's Met Office both employ the definition used by the FA ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Q Codes
The Q-code is a standardised collection of three-letter codes that each start with the letter "Q". It is an operating signal initially developed for commercial radiotelegraph communication and later adopted by other radio services, especially amateur radio. To distinguish the use of a Q-code transmitted as a question from the same Q-code transmitted as a statement, operators either prefixed it with the military network question marker "" (dit dit dah dit dah) or suffixed it with the standard Morse question mark (dit dit dah dah dit dit). Although Q-codes were created when radio used Morse code exclusively, they continued to be employed after the introduction of voice transmissions. To avoid confusion, transmitter call signs are restricted; no country is ever issued an ITU prefix starting with "Q". Codes in the range QAA–QNZ are reserved for aeronautical use; QOA–QQZ for maritime use and QRA–QUZ for all services. "Q" has no official meaning, but it is sometimes assign ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mnemonic
A mnemonic ( ) device, or memory device, is any learning technique that aids information retention or retrieval (remembering) in the human memory for better understanding. Mnemonics make use of elaborative encoding, retrieval cues, and imagery as specific tools to encode information in a way that allows for efficient storage and retrieval. Mnemonics aid original information in becoming associated with something more accessible or meaningful—which, in turn, provides better retention of the information. Commonly encountered mnemonics are often used for lists and in auditory form, such as short poems, acronyms, initialisms, or memorable phrases, but mnemonics can also be used for other types of information and in visual or kinesthetic forms. Their use is based on the observation that the human mind more easily remembers spatial, personal, surprising, physical, sexual, humorous, or otherwise "relatable" information, rather than more abstract or impersonal forms of informat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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