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Step Climb
A step climb in aviation is a series of altitude gains that improve fuel economy by moving into thinner air as an aircraft becomes lighter and becomes capable of flying in the thinner air at a higher altitude. Description Since the early days of jet aircraft and commercial travel, the technique of gradually climbing in cruise altitude as fuel burns off and the aircraft becomes lighter has been widely used by pilots. The altitude that provides the most fuel-efficient cruise (at the desired speed) at the start of a long flight, when the aircraft is fully loaded with fuel, is not the same as the altitude that provides the best efficiency at the end of the flight when most of the fuel aboard has been burned. This latter altitude is usually significantly higher than the former. By climbing gradually throughout the cruise phase of a flight, pilots can make the most economical use of their fuel. Originally, a simple ''cruise climb'' was used by pilots. This amounted to a simple, continuo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jet Aircraft
A jet aircraft (or simply jet) is an aircraft (nearly always a fixed-wing aircraft) propelled by jet engines. Whereas the engines in propeller-powered aircraft generally achieve their maximum efficiency at much lower speeds and altitudes, jet engines achieve maximum efficiency at speeds close to or even well above the speed of sound. Jet aircraft generally cruise most efficiently at about Mach 0.8 () and at altitudes around or more. The idea of the jet engine was not new, but the technical problems involved could not begin to be solved until the 1930s. Frank Whittle, an English inventor and RAF officer, began development of a viable jet engine in 1928, and Hans von Ohain in Germany began work independently in the early 1930s. In August 1939 the turbojet powered Heinkel He 178, the world's first jet aircraft, made its first flight. A wide range of different types of jet aircraft exist, both for civilian and military purposes. History After the first instance of powered f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Engine Efficiency
Engine efficiency of thermal engines is the relationship between the total energy contained in the fuel, and the amount of energy used to perform useful work. There are two classifications of thermal engines- #Internal combustion (gasoline, diesel and gas turbine-Brayton cycle engines) and # External combustion engines ( steam piston, steam turbine, and the Stirling cycle engine). Each of these engines has thermal efficiency characteristics that are unique to it. Engine efficiency, transmission design, and tire design all contribute to a vehicle's fuel efficiency. Mathematical definition The efficiency of an engine is defined as ratio of the useful work done to the heat provided. : \eta = \frac = \frac where, Q_1 is the heat absorbed and Q_1-Q_2 is the work done. Please note that the term work done relates to the power delivered at the clutch or at the driveshaft. This means the friction and other losses are subtracted from the work done by thermodynamic expansion. Thus an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RVSM
Reduced vertical separation minimum (RVSM) is the reduction, from 2,000 feet to 1,000 feet, of the standard vertical separation required between aircraft flying between flight level 290 (29,000 ft) and flight level 410 (41,000 ft). Expressed in the International System of Units (SI), it is the reduction, from 600 m to 300 m, of required vertical separation of aircraft between altitudes 8,850 and 12,500 m. This reduction in vertical separation minimum therefore increases the number of aircraft that can fly in a particular volume of controlled airspace. Historical background In 1958 the standard vertical separation of aircraft in controlled airspace was set at 1,000 feet from ground level or sea level to flight level 290, and at 2,000 feet above flight level 290. The larger minimum separations at higher altitudes was necessary because the accuracy of altimeters, used to determine altitude by measuring air pressure, decreases with height. Efforts to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North Atlantic Tracks
North Atlantic Tracks, officially titled the North Atlantic Organised Track System (NAT-OTS), is a structured set of transatlantic flight routes that stretch from the eastern North America to western Europe across the Atlantic Ocean, within the North Atlantic airspace region. They ensure that aircraft are separated over the ocean, where there is little radar coverage. These heavily travelled routes are used by aircraft flying between North America and Europe, operating between the altitudes of inclusive. Entrance and movement along these tracks is controlled by special oceanic control centres to maintain separation between aircraft. The primary purpose of these routes is to allow air traffic control to effectively separate the aircraft. Because of the volume of NAT traffic, allowing aircraft to choose their own co-ordinates would make the ATC task far more complex. They are aligned in such a way as to minimize any head winds and maximize tail winds impact on the aircraft. This ... [...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, al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flight Management System
A flight management system (FMS) is a fundamental component of a modern airliner's avionics. An FMS is a specialized computer system that automates a wide variety of in-flight tasks, reducing the workload on the flight crew to the point that modern civilian aircraft no longer carry flight engineers or navigators. A primary function is in-flight management of the flight plan. Using various sensors (such as GPS and INS often backed up by radio navigation) to determine the aircraft's position, the FMS can guide the aircraft along the flight plan. From the cockpit, the FMS is normally controlled through a Control Display Unit (CDU) which incorporates a small screen and keyboard or touchscreen. The FMS sends the flight plan for display to the Electronic Flight Instrument System (EFIS), Navigation Display (ND), or Multifunction Display (MFD). The FMS can be summarised as being a dual system consisting of the Flight Management Computer (FMC), CDU and a cross talk bus. The modern FMS w ... [...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 altimeter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Air Traffic Control
Air traffic control (ATC) is a service provided by ground-based air traffic controllers who direct aircraft on the ground and through a given section of controlled airspace, and can provide advisory services to aircraft in non-controlled airspace. The primary purpose of ATC worldwide is to prevent collisions, organize and expedite the flow of air traffic, and provide information and other support for pilots. Air traffic controllers monitor the location of aircraft in their assigned airspace by radar and communicate with the pilots by radio. To prevent collisions, ATC enforces traffic separation rules, which ensure each aircraft maintains a minimum amount of empty space around it at all times. In many countries, ATC provides services to all private, military, 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'' (known as ''flight infor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Climb (aeronautics)
An Iberia Airbus A321 on the climbout from London Heathrow Airport ">London_Heathrow_Airport.html" ;"title="Airbus A321 on the climbout from London Heathrow Airport">Airbus A321 on the climbout from London Heathrow Airport In aviation, a climb or ascent is the operation of increasing the altitude of an aircraft. It is also the logical phase of a typical flight (the ''climb phase'' or ''climbout'') following [ akeoff and preceding the cruise. During the climb phase there is an increase in altitude to a predetermined level. The opposite of a climb is a ''descent''. Climb operation A steady climb is carried out by using excess thrust, the amount by which the thrust from the power plant exceeds the drag on the aircraft.L. J. Clancy (1975): ''Aerodynamics''. Pitman Publishing Limited, London, The aircraft will climb steadily until the excess thrust falls to zero. Excess thrust might fall to zero as a result of the pilot's deliberate action in control of the output of the engine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cost-effective
Cost-effectiveness analysis (CEA) is a form of economic analysis that compares the relative costs and outcomes (effects) of different courses of action. Cost-effectiveness analysis is distinct from cost–benefit analysis, which assigns a monetary value to the measure of effect. Cost-effectiveness analysis is often used in the field of health services, where it may be inappropriate to monetize health effect. Typically the CEA is expressed in terms of a ratio where the denominator is a gain in health from a measure (years of life, premature births averted, sight-years gained) and the numerator is the cost associated with the health gain. The most commonly used outcome measure is quality-adjusted life years (QALY). Cost–utility analysis is similar to cost-effectiveness analysis. Cost-effectiveness analyses are often visualized on a plane consisting of four quadrants, the cost represented on one axis and the effectiveness on the other axis. Cost-effectiveness analysis focuses on m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Top Of Descent
In aviation, the top of descent, also referred to as the TOD or T/D, is the computed transition from the cruise phase of a flight to the descent phase, or the point at which the planned descent to final approach altitude is initiated. The top of descent is usually calculated by an on-board flight management system, and is designed to provide the most economical descent to approach altitude, or to meet some other objective (fastest descent, greatest range, etc.). The top of descent may be calculated manually as long as distance, air speed, and current altitude are known. This can be done by finding the difference between current altitude and desired altitude, dividing the result by the desired rate of descent, and then multiplying that figure by the quotient of the ground speed (not airspeed) and 60. ((C-T)/RoD)*(KGS/60)=TOD. The result dictates how far from the destination descent must begin. See also *Flight management system *Autopilot An autopilot is a system used to con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Descent (aircraft)
In aeronautics, a descent is any time period during air travel where an aircraft decreases altitude, and is the opposite of an ''ascent'' or '' climb''. Descents are part of normal procedures, but also occur during emergencies, such as rapid or explosive decompression, forcing an emergency descent to below and preferably below , respectively the maximum temporary safe altitude for an unpressurized aircraft and the maximum safe altitude for extended duration. An example of explosive decompression is Aloha Airlines Flight 243. Involuntary descent might occur from a decrease in power, decreased lift (wing icing), an increase in drag, or flying in an air mass moving downward, such as a terrain induced downdraft, near a thunderstorm, in a downburst, or microburst. Normal descents Intentional descents might be undertaken to land, avoid other air traffic or poor flight conditions (turbulence, icing conditions, or bad weather), clouds (particularly under visual flight rules), to se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
