1.
Flight instruments
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Flight instruments are the instruments in the cockpit of an aircraft that provide the pilot with information about the flight situation of that aircraft, such as altitude, airspeed and direction. They improve safety by allowing the pilot to fly the aircraft in level flight, visual flight rules require an airspeed indicator, an altimeter, and a compass or other suitable magnetic direction indicator. Instrument flight rules require a gyroscopic pitch-bank, direction and rate of turn indicator, plus a slip-skid indicator, adjustable altimeter. Flight into Instrument meteorological conditions require radio navigation instruments for precise takeoffs, the term is sometimes used loosely as a synonym for cockpit instruments as a whole, in which context it can include engine instruments, navigational and communication equipment. Many modern aircraft have electronic flight instrument systems, most regulated aircraft have these flight instruments as dictated by the US Code of Federal Regulations, Title 14, Part 91. They are grouped according to system, compass systems. It is adjustable for local barometric pressure which must be set correctly to obtain accurate altitude readings, as the aircraft ascends, the capsules expand and the static pressure drops, causing the altimeter to indicate a higher altitude. The opposite effect occurs when descending, with the advancement in aviation and increased altitude ceiling the altimeter dial had to be altered for use both at higher and lower altitudes. This modification was introduced in the early sixties after the recurrence of air caused by the confusion in the pilots mind. At higher altitudes the window will disappear, the airspeed indicator shows the aircrafts speed relative to the surrounding air. It works by measuring the pressure in the aircrafts Pitot tube relative to the ambient static pressure. The Indicated airspeed must be corrected for pressure and temperature in order to obtain the True airspeed. The instrument is color coded to indicate important airspeeds such as the speed, never-exceed airspeed. The VSI senses changing air pressure, and displays that information to the pilot as a rate of climb or descent in feet per minute, the compass shows the aircrafts heading relative to magnetic north. Errors include Variation, or the difference between magnetic and true direction, and Deviation, caused by the wiring in the aircraft. Additionally, the compass is subject to Dip Errors, while reliable in steady level flight it can give confusing indications when turning, climbing, descending, or accelerating due to the inclination of the Earths magnetic field. For this reason, the indicator is also used for aircraft operation. The attitude indicator shows the relation to the horizon
2.
Bearing (mechanical)
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A bearing is a machine element that constrains relative motion to only the desired motion, and reduces friction between moving parts. Most bearings facilitate the desired motion by minimizing friction, Bearings are classified broadly according to the type of operation, the motions allowed, or to the directions of the loads applied to the parts. Rotary bearings hold rotating components such as shafts or axles within mechanical systems, the simplest form of bearing, the plain bearing, consists of a shaft rotating in a hole. Lubrication is often used to reduce friction, a wide variety of bearing designs exists to allow the demands of the application to be correctly met for maximum efficiency, reliability, durability and performance. The term bearing is derived from the verb to bear, a bearing being an element that allows one part to bear another. The simplest bearings are bearing surfaces, cut or formed into a part, with varying degrees of control over the form, size, roughness, other bearings are separate devices installed into a machine or machine part. The most sophisticated bearings for the most demanding applications are very precise devices, the invention of the rolling bearing, in the form of wooden rollers supporting, or bearing, an object being moved is of great antiquity, and may predate the invention of the wheel. Though it is claimed that the Egyptians used roller bearings in the form of tree trunks under sleds. They are depicted in their own drawings in the tomb of Djehutihotep as moving massive stone blocks on sledges with liquid-lubricated runners which would constitute a plain bearing, there are also Egyptian drawings of bearings used with hand drills. The earliest recovered example of a rolling element bearing is a ball bearing supporting a rotating table from the remains of the Roman Nemi ships in Lake Nemi. The wrecks were dated to 40 BC, leonardo da Vinci incorporated drawings of ball bearings in his design for a helicopter around the year 1500. This is the first recorded use of bearings in an aerospace design, however, Agostino Ramelli is the first to have published sketches of roller and thrust bearings. An issue with ball and roller bearings is that the balls or rollers rub against each other causing additional friction which can be reduced by enclosing the balls or rollers within a cage, the captured, or caged, ball bearing was originally described by Galileo in the 17th century. The first practical caged-roller bearing was invented in the mid-1740s by horologist John Harrison for his H3 marine timekeeper and this uses the bearing for a very limited oscillating motion but Harrison also used a similar bearing in a truly rotary application in a contemporaneous regulator clock. The first modern recorded patent on ball bearings was awarded to Philip Vaughan and his was the first modern ball-bearing design, with the ball running along a groove in the axle assembly. Bearings played a role in the nascent Industrial Revolution, allowing the new industrial machinery to operate efficiently. For example, they saw use for holding wheel and axle to greatly reduce friction over that of dragging an object by making the act over a shorter distance as the wheel turned. The first plain and rolling-element bearings were wood closely followed by bronze, over their history bearings have been made of many materials including ceramic, sapphire, glass, steel, bronze, other metals and plastic which are all used today
3.
Glass cockpit
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A glass cockpit is an aircraft cockpit that features electronic flight instrument displays, typically large LCD screens, rather than the traditional style of analog dials and gauges. This simplifies aircraft operation and navigation and allows pilots to focus only on the most pertinent information and they are also popular with airline companies as they usually eliminate the need for a flight engineer, saving costs. In recent years the technology has become available in small aircraft. As aircraft displays have modernized, the sensors that feed them have modernized as well, traditional gyroscopic flight instruments have been replaced by electronic attitude and heading reference systems and air data computers, improving reliability and reducing cost and maintenance. GPS receivers are usually integrated into glass cockpits, glass cockpits originated in military aircraft in the late 1960s and early 1970s, an early example is the Mark II avionics of the F-111D, which featured a multi-function display. Prior to the 1970s, air operations were not considered sufficiently demanding to require advanced equipment like electronic flight displays. Also, computer technology was not at a level where sufficiently light, the increasing complexity of transport aircraft, the advent of digital systems and the growing air traffic congestion around airports began to change that. The success of the NASA-led glass cockpit work is reflected in the acceptance of electronic flight displays beginning with the introduction of the MD-80 in 1979. Airlines and their passengers alike have benefited, the safety and efficiency of flights have been increased with improved pilot understanding of the aircrafts situation relative to its environment. By the end of the 1990s, liquid-crystal display panels were increasingly favored among aircraft manufacturers because of their efficiency, earlier LCD panels suffered from poor legibility at some viewing angles and poor response times, making them unsuitable for aviation. The glass cockpit has become standard equipment in airliners, business jets and it was fitted into NASAs Space Shuttle orbiters Atlantis, Columbia, Discovery, and Endeavour, and the current Russian Soyuz TMA model spacecraft that was launched in 2002. By the end of the century glass cockpits began appearing in general aviation aircraft as well, in 2003, Cirrus Designs SR20 and SR22 became the first light aircraft equipped with glass cockpits, which they made standard on all Cirrus aircraft. The Lockheed Martin F-35 Lightning II features a panoramic cockpit display touchscreen that replaces most of the switches and toggles found in an aircraft cockpit and they look and behave very similarly to other computers, with windows and data that can be manipulated with point-and-click devices. They also add terrain, approach charts, weather, vertical displays, the improved concepts enable aircraft makers to customize cockpits to a greater degree than previously. All of the manufacturers involved have chosen to do so in one way or another—such as using a trackball, many of the modifications offered by the aircraft manufacturers improve situational awareness and customize the human-machine interface to increase safety. Modern glass cockpits might include Synthetic Vision or Enhanced Vision systems, Enhanced Vision systems add real-time information from external sensors, such as an infrared camera. All new airliners such as the Airbus A380, Boeing 787 and private jets such as Bombardier Global Express, many modern general aviation aircraft are available with glass cockpits. Systems such as the Garmin G1000 are now available on many new GA aircraft, many small aircraft can also be modified post-production to replace analogue instruments
4.
Magnetometer
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A compass is a simple example of a magnetometer, one that measures the direction of an ambient magnetic field. Magnetometers are widely used for measuring the Earths magnetic field and in geophysical surveys to detect anomalies of various types. They are also used in the military to detect submarines, consequently, some countries, such as the United States, Canada and Australia, classify the more sensitive magnetometers as military technology, and control their distribution. Magnetic fields are vector quantities characterized by strength and direction. The strength of a field is measured in units of tesla in the SI units. 10,000 gauss are equal to one tesla, measurements of the Earths magnetic field are often quoted in units of nanotesla, also called a gamma. Gaussmeters and teslameters are magnetometers that measure in units of gauss or tesla, in some contexts, magnetometer is the term used for an instrument that measures fields of less than 1 millitesla and gaussmeter is used for those measuring greater than 1 mT. There are two types of magnetometer measurement. Vector magnetometers measure the components of a magnetic field. Total field magnetometers or scalar magnetometers measure the magnitude of the magnetic field. Magnetometers used to study the Earths magnetic field may express the components of the field in terms of declination. Absolute magnetometers measure the magnitude or vector magnetic field, using an internal calibration or known physical constants of the magnetic sensor. Relative magnetometers measure magnitude or vector magnetic field relative to a fixed but uncalibrated baseline, also called variometers, relative magnetometers are used to measure variations in magnetic field. Magnetometers may also be classified by their situation or intended use, stationary magnetometers are installed to a fixed position and measurements are taken while the magnetometer is stationary. Portable or mobile magnetometers are meant to be used while in motion, laboratory magnetometers are used to measure the magnetic field of materials placed within them and are typically stationary. The performance and capabilities of magnetometers are described through their technical specifications, major specifications include Sample rate is the amount of readings given per second. The inverse is the time in seconds per reading. Sample rate is important in mobile magnetometers, the sample rate, bandwidth or bandpass characterizes how well a magnetometer tracks rapid changes in magnetic field
5.
Instrument landing system
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An instrument landing system enables aircraft to land if the pilots are unable to establish visual contact with the runway. It does this by way of transmitted radio signals, an instrument approach procedure chart is published for each ILS approach to provide the information needed to fly an ILS approach during instrument flight rules operations. A chart includes the frequencies used by the ILS components or navaids. An aircraft approaching a runway is guided by the ILS receivers in the aircraft by performing modulation depth comparisons, many aircraft can route signals into the autopilot to fly the approach automatically. An ILS consists of two independent sub-systems, the localizer provides lateral guidance, the glide slope provides vertical guidance. A localizer is an antenna array normally located beyond the end of the runway. Due to the complexity of ILS localizer and glide slope systems, localizer systems are sensitive to obstructions in the signal broadcast area, such as large buildings or hangars. Glide slope systems are limited by the terrain in front of the glide slope antennas. If terrain is sloping or uneven, reflections can create an uneven glidepath, additionally, since the ILS signals are pointed in one direction by the positioning of the arrays, glide slope supports only straight-line approaches with a constant angle of descent. Installation of an ILS can be costly because of siting criteria, ILS critical areas and ILS sensitive areas are established to avoid hazardous reflections that would affect the radiated signal. The location of these areas can prevent aircraft from using certain taxiways leading to delays in takeoffs, increased hold times. Instrument guidance system - a modified ILS to accommodate a non-straight approach, in addition to the previously mentioned navigational signals, the localizer provides for ILS facility identification by periodically transmitting a 1,020 Hz Morse code identification signal. For example, the ILS for runway 4R at John F. Kennedy International Airport transmits IJFK to identify itself and this lets users know the facility is operating normally and that they are tuned to the correct ILS. The glide slope station transmits no identification signal, so ILS equipment relies on the localizer for identification and it is essential that any failure of the ILS to provide safe guidance be detected immediately by the pilot. To achieve this, monitors continually assess the characteristics of the transmissions. If any significant deviation beyond strict limits is detected, either the ILS is automatically switched off or the navigation and identification components are removed from the carrier, either of these actions will activate an indication on the instruments of an aircraft using the ILS. Modern localizer antennas are highly directional, however, usage of older, less directional antennas allows a runway to have a non-precision approach called a localizer back course. This lets aircraft land using the signal transmitted from the back of the localizer array, highly directional antennas do not provide a sufficient signal to support a back course
6.
Pitot-static system
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A pitot-static system is a system of pressure-sensitive instruments that is most often used in aviation to determine an aircrafts airspeed, Mach number, altitude, and altitude trend. A pitot-static system generally consists of a tube, a static port. Other instruments that might be connected are air data computers, flight recorders, altitude encoders, cabin pressurization controllers. Errors in pitot-static system readings can be dangerous as the information obtained from the pitot static system. Several commercial airline disasters have been traced to a failure of the pitot-static system, the pitot-static system of instruments uses the principle of air pressure gradient. It works by measuring pressures or pressure differences and using these values to assess the speed and these pressures can be measured either from the static port or the pitot tube. The static pressure is used in all measurements, while the pressure is used only to determine airspeed. The pitot pressure is obtained from the pitot tube, the pitot pressure is a measure of ram air pressure, which, under ideal conditions, is equal to stagnation pressure, also called total pressure. The pitot tube is most often located on the wing or front section of an aircraft, facing forward, by situating the pitot tube in such a location, the ram air pressure is more accurately measured since it will be less distorted by the aircrafts structure. When airspeed increases, the ram air pressure is increased, which can be translated by the airspeed indicator, the static pressure is obtained through a static port. The static port is most often a hole on the fuselage of an aircraft. Some aircraft may have a static port, while others may have more than one. In situations where an aircraft has more than one static port, with this positioning, an average pressure can be taken, which allows for more accurate readings in specific flight situations. An alternative static port may be located inside the cabin of the aircraft as a backup for when the static port are blocked. A pitot-static tube effectively integrates the static ports into the pitot probe and it incorporates a second coaxial tube with pressure sampling holes on the sides of the probe, outside the direct airflow, to measure the static pressure. When the aircraft climbs, static pressure will decrease, some pitot-static systems incorporate single probes that contain multiple pressure-transmitting ports that allow for the sensing of air pressure, angle of attack, and angle of sideslip data. Depending on the design, such air data probes may be referred to as 5-hole or 7-hole air data probes, differential pressure sensing techniques can be used to produce angle of attack and angle of sideslip indications. The pitot-static system obtains pressures for interpretation by the pitot-static instruments, while the explanations below explain traditional, mechanical instruments, many modern aircraft use an air data computer to calculate airspeed, rate of climb, altitude and Mach number
